Theory of the Earth, Volume 1 (of 4)
by
James Hutton
Part 4 out of 6
philosophers, must vanish, in a more extensive view of the operations of
the globe; but it is certain that granite, or a species of the same kind
of stone, is thus found stratified. It is the _granit feuilletee_ of
M. de Saussure, and, if I mistake not, what is called _gneis_ by the
Germans. We have it also in our north alpine country of Scotland; of
this I have specimens, but have not seen it in its place.
Granite being thus found stratified, the masses of this stone cannot be
allowed to have any right of priority over the schistus, its companion
in the alpine countries, although M. de Saussure, whose authority I
would revere, has given it for the following reason; that it is found
the most centrical in the chains of high mountains, or in alpine
countries. Now, supposing this fact to be general, as he has found it in
the Alps, no argument for the priority of those masses can be founded
either upon the height or the situation of those granite mountains; for
the height of the mountain depends upon the solidity and strength of the
stone. Now though it is not to be here maintained that granite is the
most durable of those alpine rocks, yet as a mountain, either granite in
general, or in particular, certain species of it, may be esteemed such,
consequently, this massy stone, remaining highest in the mountainous
region, will naturally be considered as the centre, and according to
this rule, as having the pre-eminence in point of seniority.
The rock which stands in competition with granite for the title of
primitive in the order of mountains, is that micaceous stratified stone
which is formed chiefly of quartz, but which admits of great variety
like the granite. The difference between those two bodies does not
consist in the materials of which they are composed, for, in their
varieties, they may be in this respect the same, but in a certain
regularity of composition, in this alpine stone, which evidently arises
from stratification or subsidence in water.
If we shall thus consider all the varieties of this alpine stone as
being of one kind, and call it granite, then we shall distinguish in
this body two different species, from whence perhaps some interesting
conclusion may be formed with regard to the operations of the globe.
These two species are, _first_, granite regular in its composition, or
stratified in its construction; and, _secondly_, granite in mass, or
irregular in its construction. Let us now endeavour to make use of these
generalizations and distinctions.
In examining the great diversity of our whinstone, trap, or basaltes, it
is found at last to granulate into granite; at the same time those two
different species of rock-stone may be distinguished. A perfect granite
has not in its composition necessarily any argillaceous earth, farther
than may be in the natural constitution of its distinct parts; whereas,
a perfect basalt may have abundance of this substance, without any
quartz or any siliceous body. A perfect granite, is, therefore, an
extremely hard stone, having quartz and feldspar for its basis; but a
perfect whin or basaltes may be extremely soft, so as to cut easily with
a knife. In like manner granite is a composition which graduates into
porphyry; but porphyry is only whinstone of a harder species. Therefore,
though perfectly distinct, those three things graduate into each other,
and may be considered as the same.
Granite and whinstone, or basaltes, though distinct compositions, thus
graduating into each other; and whinstone, as well as porphyry, being
without doubt a species of lava, we may consider the granite which is
found in mass without stratification, in like manner as we do the masses
of whinstone, basaltes, or Swedish trap, as having flowed in the bowels
of the earth, and thus been produced by the chance of place, without any
proper form of its own, or in an irregular shape and construction. In
this manner would be explained the irregular shape or structure of those
granite masses; and thus great light would be thrown upon the waved
structure of the stratified alpine stone, which, though it has not been
made to flow, has been brought to a great degree of softness, so as to
have the original straight lines of its stratification changed to
those undulated or waving lines which are in some cases extremely much
incurvated.
It remains only to confirm this reasoning, upon our principles, by
bringing actual observation to its support; and this we shall do from
two of the best authorities. The Chevalier de Dolomieu, in describing
the volcanic productions of Etna, mentions a lava which had flowed from
that mountain, and which may be considered as a granite. But M. de
Saussure has put this matter out of doubt by describing most accurately
what he had seen both in the Alps and at the city of Lyons. These are
veins of granite which have flowed from the contiguous mass into the
stratified stone, and leave no doubt with regard to this proposition,
that the granite had flowed in form of subterranean lava, although M. de
Saussure has drawn a very different conclusion from this appearance. I
have also a specimen from this country of a vein of granite in a granite
stone, the vein being of a smaller grain than that of the rock which it
traverses.[20]
[Note 20: This is what I had wrote upon, the subject of granite, before
I had acquired such ample testimony from my own observations upon
that species of rock. I have given some notice, in the 3d vol. of the
Transactions of the Edinburgh R.S. concerning the general result of
those observations, which will be given particularly in the course of
this work.]
It will thus appear, that the doctrine which of late has prevailed, of
primitive mountains, or something which should be considered as original
in the construction of this earth, must be given up as a false view of
nature, which has formed the granite upon the same principle with that
of any other consolidated stratum; so far as the collection of different
materials, and the subsequent fusion of the compound mass, are necessary
operations in the preparation of all the solid masses of the earth.
Whatever operations of the globe, therefore, may be concluded from the
composition of granite masses, as well as of the alpine strata, these
must be considered as giving us information with regard to the natural
history of this earth; and they will be considered as important, in
proportion as they disclose to us truths, which from other strata might
not be so evident, or at all made known.
Let us now examine the arguments, which, may be employed in favour of
that supposition of primitive mountains.
The observations, on which naturalists have founded that opinion of
originality in some of the component parts of our earth, are these;
_first_, They observe certain great masses of granite in which
stratification is not to be perceived; this then they say is an original
mass, and it is not to be derived from any natural operation of the
globe; _secondly_, They observe considerable tracts of the earth
composed of matter in the order of stratification as to its general
composition, but not as to its particular position, the vertical
position here prevailing, instead of the horizontal which is proper to
strata formed in water; this, therefore, they also term primitive, and
suppose it to be from another origin than that of the subsidence of
materials moved in the waters of the globe; _lastly_, They observe both
strata and masses of calcareous matter in which they cannot distinguish
any marine body as is usual in other strata of the same substance; and
these calcareous masses being generally connected with their primitive
mountains, they have also included these collections of calcareous
matter, in which marine bodies are not observed, among the primitive
parts which they suppose to be the original construction of this globe.
It may be proper to see the description of a calcareous alpine mountain.
M. de Saussure gives us the following observations concerning a mountain
of this kind in the middle of the Alps, where the water divides in
running different ways towards the sea. It is in describing the passage
of the Bon-Homme, (Tom. 2. V. dans les Alpes).
"Sec. 759. Sur la droite ou au couchant de ces rochers, on voit une
montagne calcaire etonnante dans ce genre par la hardiesse avec laquelle
elle eleve contre le ciel ses cimes aigues et tranchantes, taillees
a angles vifs dans le costume des hautes cimes de granit. Elle est
pourtant bien surement calcaire, je l'ai observee de pres, et on
rencontre sur cette route les blocs qui s'en detachent.
"Cette pierre porte les caracteres des calcaires les plus anciennes; sa
couleur est grise, son grain assez fin, on n'y appercoit aucun vestige
de corps organises; ses couches sont peu epaisses, ondees et coupees
frequemment par des fentes paralleles entr'elles et perpendiculaires a
leurs plans. On trouve aussi parmi ces fragmens des breches calcaires
grises."
Here is a mountain which will rank with the most primitive of the earth;
But why? only because it is extremely consolidated without any mark of
organised body. Had there been in this mountain but one single shell, we
should not then have scrupled to conclude that the origin of this lofty
mountain had been the same with every marble or limestone in the earth.
But though, from the structure of this stone, there is no mark of its
having been formed immediately of the calcareous parts of animals, there
is every mark of those calcareous strata having been formed like other
marbles by deposit in the waters of the globe.
These two things are also homologated by the equal or perfect
consolidation of their substance; for, as it is to be proved that
all stratified marbles have been consolidated by the fusion of their
substance, we must attribute the same consolidating cause to those
alpine masses; the frequent veins that divide those calcareous strata
which M. de Saussure has here described, also prove the nature of the
consolidating cause, (see Chap. 1. page 111.).
This mountain, considered by itself, may perhaps afford no data by which
a naturalist might read the circumstances of its origin. But, Is a
theory of the earth to be formed upon such a negative observation? and,
Is there any particular in this mountain, that may not be shown in
others of which the origin is not in any degree doubtful?
It is not to be disputed, that there are parts of the solid body of our
earth which may be considered as primary or prior, compared with others
that are posterior, in relation to the time of their formation, and much
less changed with regard to the state in which they had been originally
formed:--But it is here denied, that there are any parts of the earth
which do not appear to have had the same origin with all the rest, so
far as this consists in the collection of materials deposited at the
bottom of the waters[21]; for there is no solid mass of land that may
not be traced to this origin, either from its composition, or from its
local connection with other masses, the nature of which in this respect
are known. We have already given examples of this from sufficient
authority. The evidence, therefore, of those primary masses being
original in relation to the natural operations of the globe, is reduced
to this assertion, that there are no vestiges of organised bodies to be
found in those primary masses. Let us now examine how far this testimony
for the originality of those masses is to be admitted in fact and sound
reasoning.
[Note 21: There are no collection of those alpine masses in which may
not be found in some of them sand, mica, and gravel; but these materials
prove the existence of an earth, on which those fragments of greater
masses had been formed, and more or less worn by attrition.]
The matter in question at present is this, that there are certain tracts
of countries in which no vestige of organised bodies are found; now, let
us suppose the fact to be true or well grounded, Can we conclude
from this that there had been originally no organised bodies in the
composition of those masses?--Such a conclusion could only be formed in
making a supposition, that every organised body deposited in a mass
of matter, whether homogeneous or heterogeneous, should be preserved
without change, while the collected mass, in which it had been
deposited, changes as much as possible by the operation both of fire and
water. But this supposition is erroneous, and cannot be admitted; and
the study of marbles will demonstrate this truth, that the calcareous
relics of organised bodies are changed, in the consolidating operations
of the globe, in every degree, from the smallest alteration to the
greatest, when they become indistinguishable any farther to our sight.
Therefore, from the supposition of no appearance of marine bodies in the
pretended primitive masses, there is no sufficient evidence or reason to
conclude, that those masses have not had a marine origin; because, the
traces of organised bodies may be obliterated by the many subsequent
operations of the mineral region; and which operations, the present
state of those masses certify beyond dispute.
We are now to examine the fact, how far the ground on which that false
reasoning had been founded is strictly true.
In the first place, then, it must be considered, that the alledged fact
is nothing but a negative assertion, importing that no mark of organised
bodies had been observed, in certain stones and strata which some
naturalists have examined with that view. But, though many naturalists
have looked for them without success, it does not follow that such marks
may not be found; it indeed proves that such a task is difficult, and
the success of it, to a particular, most precarious; accident, however,
may bring about what the greatest industry has not been able to attain.
Secondly, there is good reason to believe that this asserted negation
is not absolutely true; for I have in my possession what I consider as
proof of the contrary; I found it in Wales, and I think it is in what
may be considered as primitive mountains;--it is the mark of shells in a
stone of that kind.
Thus, I had formed my opinion with regard to this alleged fact, long
before I had seen any description either of the Alps or Pyrennean
mountains; and now I have no reason to change that opinion. It may
indeed be alleged, that the strata of marble or limestone, containing
marine bodies found in those mountains, are secondary strata, and not
the primitive. To this I can give no reply, as the descriptions given of
those strata do not enable me to decide this point.
At the village of Mat, under the Mont Blatten for example, there is a
quarry of schistus or black slate, in which are often found the print
and the bones of fishes. (Discours sur l'Histoire Naturelle de la
Suisse, page 225.). If this may be considered as an alpine or primitive
schistus, it would be decisive of the question: But it would require to
have it well ascertained that this schistus is truly one of those which
are esteemed primitive, or that it is properly connected with them.
But though I cannot find in those interesting descriptions which we now
have got, any one which is demonstrative of this truth, that calcareous
marine objects are found in the primitive strata, this is not the
case with regard to another object equally important in deciding this
question, Whether the primitive strata are found containing the marks of
organised bodies?
M. de Dellancourt, in his _Observations Mineralogiques_, Journal de
Physique Juillet 1786, in describing the mountains of Dauphine, gives us
the following fact with regard to those alpine vertical strata.
"La pierre constituante de la montagne d'Oris est en general le _Kneifs_
ou la roche feuilletee mica et quartz a couches plus ou moins ferrees
quelquefois le schorl en roche penetre de steatite. Les couches varient
infiniment quant a leur direction et a leur inclinaisons. Cette montagne
est cultivee et riche dans certain cantons, surtout autour du village
d'Oris, mais elle est tres-escarpee dans beaucoup d'autres. Entre le
village d'Oris et celui du Tresnay est une espece de combe assez creuse
formee par la chute des eaux des cimes superieures des rochers. Cette
combe offre beaucoup de schiste dont les couches font ou tres-inclinees
ou perpendiculaires. Entre ces couches il s'en est trouve de plus noires
que les autres et capable de bruler, mais difficilement. Les habitans
ont extrait beaucoup de cette matiere terreuse, et lui ont donne le nom
de charbon de terre. Ils viennent meme a bout de la faire bruler, et
de s'en servir l'hiver en la melant avec du bois. Ce schiste noir
particulier m'a paru exister principalement dans les endroits ou les
eaux se sont infiltrees entre les couches perpendiculaires, et y ont
entraine diverse matieres, et sur-tout des debris de vegetaux que
j'ai encore retrouves a demi-noirs, pulverulens et comme dans un etat
charbonneux."
This formation of coal, by the infiltration of water and carrying in of
vegetable bodies, certainly cannot be admitted of; consequently, from
this description, there would seem to be strata of coal alternated with
the alpine schisti. But the formation of mineral coal requires vegetable
matter to have been deposited along with those earthy substances, at the
bottom of the sea. The production of vegetable bodies, again, requires
the constitution of sea and land, and the system of a living world,
sustaining plants at least, if not animals.
In this natural history of the alpine schisti, therefore, we have a
most interesting fact, an example which is extremely rare. Seldom are
calcareous organised bodies found among those alpine strata, but still
more rarely, I believe, are the marks of vegetable bodies having
contributed in the formation of those masses. But however rare this
example, it is equally decisive of the question, Whether the alpine
schisti have had a similar origin as the other strata of the globe,
in which are found abundance of animal and vegetable bodies, or their
relics? and we are authorised to say, that since those perfect alpine
strata of Dauphine have had that origin, all the alpine schisti of the
globe have been originally formed in a similar manner. But to put this
matter out of doubt:
In this summer 1788, coming from the Isle of Man, Mr Clerk and I
traveled through the alpine schistus country of Cumberland and
Westmoreland. We found a limestone quarry upon the banks of Windermere,
near the Low-wood Inn. I examined this limestone closely, but despaired
of finding any vestige of organised body. The strata of limestone
seem to graduate into the slate or schistus strata, between which the
calcareous are placed. Fortunately, however, I at last found a fragment
in which I thought to perceive the works of organised bodies in a
sparry state; I told Mr Clerk so, and our landlord Mr Wright, who had
accompanied us. I have brought home this specimen, which I have now
ground and polished; and now it is most evidently full of fragments of
entrochi. Mr Wright then told me he had seen evident impressions of
marine objects, as I understood from the description, in the slate of
those mountains; and he was to send me specimens so soon as he could
procure them.
Here is one specimen which at once overturns all the speculations formed
upon that negative proposition. The schistus mountains of Cumberland
were, in this respect, as perfect primitive mountains as any upon the
earth, before this observation; now they have no claim upon that score,
no more than any limestone formed of shells.
When I first announced my belief that such objects in natural history
might be found, I little thought to have seen it realised, to such a
degree as has now happened in the little circle of my knowledge. In the
summer 1791,
Professor Playfair was to pass through Cumberland. I begged that he
would inquire of Mr Wright, at the Low-wood Inn, for those objects which
he was to endeavour to procure for me, and to examine the limestone
quarry in which I had found the specimen with entrochi. He went through
another part of those primary mountains, and has found examples of this
kind in the schisti; concerning which he has written me the following
account.
"In a visit which I made to the Lakes of Cumberland in September 1791,
in company with the Hon. Francis Charteris, I met with a limestone
full of marine objects, though from its position it is certainly to be
reckoned among the primary strata. The place where we found this stone
was in the district of Lancashire, that is west of Windermere Lake, on
the road from Ambleside to the north end of Coniston Lake, and not far
from the point when you come in sight of the latter. Just about this
spot we happened to meet with one of those people who serve as guides
to travelers in those parts, and who told us, among other things, that
stones with shells in them were often found not far from where we were
then walking. We immediately began to look about for specimens of that
kind, and soon met with several; the most remarkable of which was in a
rock that rose a little above the surface, about 300 or 400 yards to
the right of the road. It was a part of a limestone stratum, nearly
vertical, and was full of bivalves with the impressions as strong as
in a common secondary limestone. The strata on both sides had the same
inclination, and were decidedly primary, consisting of the ordinary
micaceous schistus. This however I need not remark to you, who know so
well from your own observations that the whole of the country I am now
speaking of has every character of a primary one. I, only mention it,
that it may not be supposed that the rock in question was some fragment
of a secondary stratum that remained, after the rest was washed away,
superincumbent on the primary.
"After I had seen this rock, I recollected that you had told me of
something of the same kind that you saw in a quarry at Low-wood Inn; and
it may be that both belonged to the same stratum or body of strata; for
the direction of the strata, as nearly as I could observe, was from S.W.
to N.E.; and this also is nearly the bearing of Low-wood from the place
where we now were. I send you a specimen, which you can compare with
those you brought from the lime quarry at Low-wood."
I have examined this specimen, and find it to be the common schistus
of that country, only containing many bivalve shells and fragments of
entrochi and madrapore bodies, and mixed with pyrites.
I have already observed that one single example of a shell, or of its
print, in a schistus, or in a stone stratified among those vertical or
erected masses, suffices to prove the origin of those bodies to have
been, what I had maintained them to be, water formed strata erected from
the bottom of the sea, like every other consolidated stratum of the
earth. But now, I think, I may affirm, that there is not, or rarely, any
considerable extent of country of that primary kind, in which some mark
of this origin will not be found, upon careful examination; and now I
will give my reason for this assertion. I have been examining the south
alpine country of Scotland, occasionally, for more than forty years
back, and I never could find any mark of an organised body in the
schistus of those mountains. It is true that I know of only one place
where limestone is found among the strata; this is upon Tweed-side near
the Crook. This quarry I had carefully examined long ago, but could find
no mark of any organised body in it. I suppose they now are working some
other of the vertical strata near those which I had examined; for, in
the summer 1792, I received a letter from Sir James Hall, which I shall
now transcribe. It is dated at Moffat, June 2. 1792.
"As I was riding yesterday between Noble-house and Crook, on the road to
this place, I fell in with a quarry of alpine limestone; it consists of
four or five strata, about three feet thick, one of them single, and the
rest contiguous; they all stand between the strata of slate and schist
that are at the place nearly vertical. In the neighbourhood, a slate
quarry is worked of a pure blue slate; several of the strata of slate
near the limestone are filled with fragments of limestone scattered
about like the fragments of schist in the sandstone in the neighbourhood
of the junction on our coast.[22]
[Note 22: This has a reference to very curious observations which we
made upon the east coast where these mountains terminate, and which I am
to describe in the course of this work.]
"Among the masses of limestone lately broken off for use, and having the
fractures fresh, I found the forms of cockles quite distinct; and in
great abundance.--I send you three pieces of this kind," etc.
It may perhaps be alleged that those mountains of Cumberland and
Tweedale are not the primary mountains, but composed of the secondary
schistus, which is every where known to contain those objects belonging
to a former earth. Naturalists who have not the opportunity of
convincing themselves by their proper examination, must judge with
regard to that geological fact by the description of others. Now it is
most fortunate for natural history, that it has been in this range of
mountains that we have discovered those marks of a marine origin; for,
I shall afterwards have occasion to give the clearest light into this
subject, from observations made in other parts of those same mountains
of schist, by which it will be proved that they are the primary
strata; and thus no manner of doubt will then remain in the minds
of naturalists, who might otherwise suspect that we were deceiving
ourselves, by mistaking the secondary for the primitive schistus.
I have only farther to observe, that those schisti mountains of Wales,
of Cumberland, and of the south alpine part of Scotland, where these
marine objects have been found, consist, of that species of stone which
in some places makes the most admirable slate for covering houses; and,
in other parts, it breaks into blocks that so much resemble wood in
appearance, that, without narrow inspection, it might pass for petrified
wood.
We are therefore to conclude that the marks of organised bodies in those
primary mountains are certainly found; at the same time the general
observation of naturalists has some foundation, so far as the marks of
organised bodies are both rarely to be met with in those masses, and not
easily distinguished as such when they are found.
But this scarcity of marine objects is not confined to those primary
mountains, as they are called; for among the most horizontal strata, or
those of the latest production, there are many in which, it is commonly
thought, no marine calcareous objects are to be found; and this is a
subject that deserves to be more particularly considered, as the theory
may thus receive some illustration.
Sandstone, coal, and their accompanying strata, are thought to be
destitute of calcareous marine productions, although many vestiges of
plants or vegetable productions are there perceived. But this general
opinion is neither accurate nor true; for though it be true that in the
coal and sandstone strata it is most common to find marks of vegetable
production, and rarely those calcareous bodies which are so frequent in
the limestone, yet it is not unusual for coal to be accompanied
with limestone formed of shells and corals, and also with ironstone
containing many of those marine objects as well as wood. Besides,
sandstone frequently contains objects which have been organised bodies,
but which do not belong to the vegetable kingdom, at least to no plant
which grows upon the land, but would seem to have been some species of
zoophite perhaps unknown.
I have also frequently seen the vestige of shells in sandstone, although
in these strata the calcareous bodies are in general not perceived.
The reason of this is evident. When there is a small proportion of the
calcareous matter in the mass of sand which is pervious to steam and to
the percolation of water, the calcareous bodies may be easily dissolved,
and either carried away or dispersed in the mass; or even without being
thus dispersed by means of solution, the calcareous matter may be
absorbed by the siliceous substance of the stratum by means of fusion,
or by heat and cementation. The fact is, that I have seen in sandstone
the empty mould of marine shells with some siliceous crystallization,
so far as I remember, which corresponded perfectly with that idea. The
place I saw this was in a fine white sandstone accompanying the coal,
upon the sea side at Brora in Sutherland.
Mineralogy is much indebted to Mr Pallas for the valuable observations
which he has given of countries so distant from the habitations of
learned men. The physiology of the globe has also been enriched with
some interesting observations from the labours of this learned traveller.
But besides giving us facts, Mr Pallas has also reasoned upon the
subject, and thus entered deep into the science of Cosmogeny; here it
is that I am afraid he has introduced some confusion into the natural
history of the earth, in not properly distinguishing the mineral
operations of the globe, and those again which belong entirely to the
surface of the earth; perhaps also in confounding the natural effects of
water upon the surface of the earth, with those convulsions of the sea
which may be properly considered as the accidental operations of the
globe. This subject being strictly connected with the opinions of that
philosopher with regard to primitive mountains, I am obliged to examine
in this place matters which otherwise might have come more properly to
be considered in another.
M. Pallas in his _Observations sur la formation des montagnes_, (page
48) makes the following observations.
"J'ai deja dit que _la bande de montagnes primitives schisteuses_
heterogenes, qui, par toute la terre, accompagne les chaines
granitiques, et comprend les roches quartzeuses et talceuses mixtes,
trapezoides, serpentines, le schiste corne, les roches spathiques et
cornees, les grais purs, le porphyre et le jaspre, tous rocs feles
en couches, ou presque perpendiculaires, ou du moins tres-rapidement
inclinees, (les plus favorables a la filtration des eaux), semble
aussi-bien que le granit, anterieure a la creation organisee. Une raison
tres-forte pour appuyer cette supposition, c'est que la plupart de ces
roches, quoique lamelleuse en facon d'ardoise, n'a jamais produit
aux curieux la moindre trace de petrifactions ou empreintes de corps
organises. S'il s'en est trouve, c'est apparemment dans des fentes de
ces roches ou ces corps ont ete apportes par un deluge, et encastrees
apres dans une matiere infiltree, de meme qu'on a trouve des restes
d'Elephans dans le filon de la mine d'argent du Schlangenberg.[23] Les
caracteres par lesquels plusieurs de ces roches semblent avoir souffert
des effets d'un feu-tres-violent, les puissantes veines et amas des
mineraux les plus riches qui se trouvent principalement dans la bande
qui en est composee, leur position immediate sur le granit, et meme le
passage, par lequel on voit souvent en grand, changer le granit en une
des autres especes; tout cela indique une origine bien plus ancienne,
et des causes bien differentes de celles qui ont produit les montagnes
secondaires."
[Note 23: This is a very natural way of reasoning when a philosopher
finds a fact, related by some naturalists, that does not correspond with
his theory or systematic view of things. Here our author follows the
general opinion in concluding that no organised body should be found in
their primitive strata; when, therefore, such an object is said to have
been observed, it is supposed that there may have been some mistake with
regard to the case, and that all the circumstances may not have been
considered. This caution with regard to the inaccurate representation of
facts, in natural history, is certainly extremely necessary; the relicts
of an elephant found in a mineral vein, is certainly a fact of that
kind, which should not be given as an example in geology without the
most accurate scientifical examination of the subject.]
Here M. Pallas gives his reason for supposing those mountains primitive
or anterior to the operations of this globe as a living world; _first_,
because they have not, in general, marks of animals or plants; and that
it is doubtful if they ever properly contain those marks of organised
bodies; _secondly_, because many of those rocks have the appearance of
having suffered the effects of the most violent fire. Now, What are
those effects? Is it in their having been brought into a fluid state of
fusion. In that case, no doubt, they may have been much changed from the
original state of their formation; but this is a very good reason why,
in this changed state, the marks of organised bodies, which may have
been in their original constitution, should be now effaced.
The _third_ reason for supposing those mountains primitive, is taken
from the metallic veins, which are found so plentifully in these masses.
Now, had these masses been the only bodies in this earth in which those
mineral veins were found, there might be some species of reason for
drawing the conclusion, which is here formed by our philosopher. But
nothing is so common (at least in England) as mineral veins in the
strata of the latest formation, and in those which are principally
formed of marine productions; consequently so far from serving the
purpose for which this argument was employed, the mineral veins in the
primitive mountains tend to destroy their originality, by assimilating
them in some respect with every other mass of strata or mountain upon
the globe.
_Lastly_, M. Pallas here employs an argument taken from an appearance
for which we are particularly indebted to him, and by which the
arguments which have been already employed in denying the originality
of granite is abundantly confirmed. It has been already alleged, that
granite, porphyry, and whinstone, or trap, graduate into each other; but
here M. Pallas informs us that he has found the granite not only changed
into porphyry, but also into the other alpine compositions. How an
argument for the originality of these mountains can be established upon
those facts, I am not a little at a loss to conceive.
The general mineralogical view of the Russian dominions, which we have,
in this treatise, may now be considered with regard to that distinction
made by naturalists, of primitive, secondary, and tertiary mountains, in
order to see how far the observations of this well informed naturalist
shall be found to confirm the theory of the earth which has been already
given, or not.
The Oural mountains form a very long chain, which makes the natural
division betwixt Europe and Asia, to the north of the Caspian. If in
this ridge, as a centre of elevation, and of mineral operations, we
shall find the greatest manifestation of the violent exertion of
subterraneous fire, or of consolidating and elevating operations; and if
we shall perceive a regular appearance of diminution in the violence or
magnitude of those operations, as the places gradually recede from
this centre of active force; we may find some explanation of those
appearances, without having recourse to conjectures which carry no
scientific meaning, and which are more calculated to confound our
acquired knowledge, than to form any valuable distinction of things. Let
us consult M. Pallas how far this is the case, or not.
After having told us that all those various alpine schisti, jaspers,
porphyries, serpentines, etc. in those mountains, are found mutually
convertible with granite, or graduating into each other, our author thus
continues, (p. 50).
"On entrevoit de certaines loix a l'egard de l'arrangement respectif
de cet ordre secondaire d'anciennes roches, par tous les systemes de
montagnes qui appartiennent a l'Empire Russe. La chaine Ouralique, par
exemple, a du cote de l'Orient sur tout sa longueur, une tres-grande
abondance de schistes cornes, serpentins et talceux, riches en filons
de cuivre, qui forment le principal accompagnement du granite, et en
jaspres de diverses couleurs plus exterieurs et souvent comme entrelaces
avec les premiers, mais formant des suites de montagnes entieres, et
occupant de tres-grands espaces. De ce meme cote, il y parait beaucoup
de quartz en grandes roches toutes pures, tant dans la principale chaine
que dans le noyau des montagnes de jaspre, et jusques dans la plaine.
Les marbres spateux et veines, percent en beaucoup d'endroits. La
plupart de ces especes ne paraissent point du tout a la lisiere
occidentale de la chaine, qui n'est presque que de roche melangee de
schistes argileux, alumineux, phlogistique, etc. Les filons des mines
d'or melees, les riches mines de cuivre en veines et chambrees, les
mines de fer et d'aimant par amas et montagnes entieres, sont l'apanage
de la bande schisteuse orientale; tandis que l'occidentale n'a pour elle
que des mines de fer de depots, et se montre generalement tres-pauvre en
metaux. Le granit de la chaine qui borde la Siberie, est recouvert du
cote que nous connaissons de roches cornees de la nature des pierres a
fusil, quelquefois tendant a la nature d'un grais fin et de schistes
tres-metallieres de differente composition. Le jaspre n'y est qu'en
filons, ou plans obliques, ce qui est tres-rare pour la chaine
Ouralique, et s'observe dans la plus grande partie de la Siberie, a
l'exception de cette partie de sa chaine qui passe pres de la mer
d'Okhotsk, ou le jaspre forme derechef des suites de montagnes, ainsi
que nous venons de le dire des monts Ourals; mais comme cette roche
tient ici le cote meridionale de la chaine Siberienne, et que nous
ne lui connaissons point ce cote sur le reste de sa longueur, il se
pourrait que le jaspre y fut aussi abondant. Il faudrait, au reste, bien
plus de fouilles et d observations pour etablir quelque chose de certain
sur l'ordre respectif qu'observent ces roches."
I would now ask, if in all this account of the gradation of rock from
the Oural mountains to the sandy coast of the Baltic, there is to be
observed any clear and distinctive mark of primitive, secondary, and
tertiary, mountains, farther than as one stratum may be considered as
either prior or posterior to another stratum, according to the order of
superposition in which they are found. We have every where evident marks
of the formation of strata by materials deposited originally in water;
for the most part, there is sufficient proof that this water in which
those materials had been deposited was the sea; we are likewise assured
that the operations of this living world producing animals, must
have, for a course of time, altogether inconceivably been exerted,
in preparing materials for this mass; and, lastly, from the changed
constitution of those masses, we may infer certain mineral operations
that melt the substance and alter the position of those horizontal
bodies. Such is the information which we may collect from this mineral
description of the Russian Dominions.
If we compare some of the Oural mountains with the general strata of
the Russian plains, then, as to the contained minerals, we may find a
certain diversity in those two places; at the same time, no greater
perhaps than may be found betwixt two different bodies in those same
plains, for example, chalk and flint. But when we consider those bodies
of the earth, or solid strata of the globe, in relation to their proper
structure and formation, we surely can find in this description nothing
on which may be founded any solid opinion with regard to a different
original, however important conclusions may perhaps be formed with
regard to the operations of the globe, from the peculiar appearances
found in alpine.
From this detail of what is found in the Oural mountains, and in the
gradation of country from those mountains to the plains of Russia, we
have several facts that are worthy of observation. First extensive
mountains of jasper. I have a specimen of this stone; it is striped red
and green like some of our marly strata. It has evidently been formed of
such argillaceous and siliceous materials, not only indurated, so as to
lose its character, as an argillaceous stone, but to have been brought
into that degree of fusion which produces perfect solidity. Of the same
kind are those hornstein rocks of the nature of flint, sometimes tending
to the nature of a fine sandstone. Here is the same induration of
sandstone by means of fusion, that in the argillaceous strata has
produced jasper. But oblique veins of jasper are represented as
traversing these last strata; now this is a fact which is not
conceivable in any other way, than by the injection or transfusion of
the fluid jasper among those masses of indurated strata.
All this belongs to the east side of the mountains. On the west, again,
we find the same species of strata; only these are not changed to such a
degree as to lose their original character or construction, and thus to
be termed differently in mineralogy.
Our author then proceeds. (p. 53.)
"Nous pourrons parler plus decisivement sur les _montagnes secondaires
et tertiaires_ de l'Empire, et c'est de celles-la, de la nature, de
l'arrangement et du contenu de leurs couches, des grandes inegalites et
de la forme du continent d'Europe et d'Asie, que l'on peut tirer avec
plus de confiance quelques lumieres sur les changemens arrives aux
terres habitables. Ces deux ordres de montagnes presentent la chronique
de notre globe la plus ancienne, la moins sujette aux falsifications, et
en meme-tems plus lisible que le caractere des chaines primitives;
ce font les archives de la nature, anterieures aux lettres et aux
traditions les plus reculees, qu'il etoit reserve a notre siecle
observateur de feuiller, de commenter, et de mettre au jour, mais que
plusieurs siecles apres le notre n'epuiseront pas.
"Dans toute l'etendue de vastes dominations Russes, aussi bien que
dans l'Europe entiere, les observateurs attentifs ont remarque
que generalement la band schisteuse des grandes chaines se trouve
immediatement recouverte ou cottee par la _bande calcaire_. Celle-ci
forme deux ordres de montagnes, tres-differentes par la hauteur, la
situation de leurs couches, et la composition de la pierre calcaire qui
les compose; difference qui est tres-evidente dans cette bande calcaire
qui forme la lisiere occidentale de toute la chaine Ouralique, et dont
le plan s'etend par tout le plat pays de la Russie. L'on observerait
la meme chose a l'orient de la chaine, et dans toute l'etendue de la
Siberie, si les couches calcaires horizontales n'y etaient recouvertes
par les depots posterieures, de facon qu'il ne parait a la surface que
les parties les plus faillantes de la bande, et si ce pays n'etoit trop
nouvellement cultive et trop peu exploite par des fouilles et autres
operations, que des hommes industrieux ont pratique dans les pays
anciennement habites. Ce que je vais exposer sur les deux ordres de
montagnes calcaires, se rapportera donc principalement a celles qui sont
a l'occident de la chaine Ouralique.
"Ce cote de la dite chaine consiste sur cinquante a cent verstes de
largeur, de roche calcaire solide, d'un grain uni, qui tantot ne
contient aucune trace de productions marines, tantot n'en conserve
que des empreintes aussi legeres qu'eparses. Cette roche s'eleve en
montagnes d'une hauteur tres-considerable, irregulieres, rapides, et
coupees de vallons escarpes. Ses couches, generalement epaisses, ne sont
point de niveau, mais tres-inclinees a l'horizon, paralleles, pour la
plupart, a la direction de la chaine, qui est aussi ordinairement celle
de la bande schisteuse;--au lieu que du cote de l'orient les couches
calcaires sont au sens de la chaine en direction plus ou moins
approchante de l'angle droite. L'on trouve dans ces hautes montagnes
calcaires de frequentes grottes et cavernes tres-remarquables, tant
par leur grandeur que par les belles congelations et crystallizations
stalactiques dont elles s'ornent. Quelques-unes de ces grottes ne
peuvent etre attribuees qu'a quelque bouleversement des couches;
d'autres semblent devoir leur origine a l'ecoulement des sources
souterraines qui ont amolli, ronge et charrie une partie de la roche qui
en etoit susceptible.
"En s'eloignant de la chaine, on voit les couches calcaires s'aplanir
assez rapidement, prendre une position horizontale, et devenir
abondantes en toute forte de coquillages, de madrepores, et d'autres
depouilles marines. Telles on les voit par-tout dans les vallees les
plus basses qui se trouvent aux pieds des montagnes (comme aux environs
de la riviere d'Oufa); telles aussi, elles occupent tout l'etendue de la
grande Russie, tant en collines qu'en plat pays; solides tantot et comme
semees de productions marines; tantot toutes composees de coquilles et
madrepores brisees, et de ce gravier calcaire qui se trouve toujours sur
les parages ou la mer abonde en pareilles productions; tantot, enfin,
dissoutes en craie et en marines, et souvent entremelees de couches de
gravier et de cailloux roules."
How valuable for science to have naturalists who can distinguish
properly what they see, and describe intelligibly that which they
distinguish. In this description of the strata, from the chain of
mountains here considered as primitive, to the plains of Russia, which
are supposed to be of a tertiary formation, our naturalist presents us
with another species of strata, which he has distinguished, on the one
hand, in relation to the mountains at present in question, and on the
other, with regard to the strata in the plains, concerning which there
is at present no question at all. Now, let us see how these three things
are so connected in their nature, as to form properly the contiguous
links of the same chain.
The primary and tertiary masses are bodies perfectly disconnected;
and, without a medium by which they might be approached, they would be
considered as things differing in all respects, consequently as having
their origins of as opposite a nature as are their appearances. But the
nature and formation of those bodies are not left in this obscurity;
for, the secondary masses, which are interposed, participate so
precisely of what is truly opposite and characteristic in the primary
and tertiary masses, that it requires nothing more than to see this
distinction of things in its true light, to be persuaded, that in those
three different things we may perceive a certain gradation, which
here takes place among the works of nature, and forms three steps
distinguishable by a naturalist, although in reality nothing but the
variable measure of similar operations.
We are now to assimilate the primary and tertiary masses, which are so
extremely different, by means of the secondary masses, which is the
mean. The primary and tertiary differ in the following respects: The one
of these contains the relicts of organised bodies which are not observed
in the other. But in the species containing these distinguishable
bodies, the natural structure and position of the mass is little
affected, or not so much as to be called into doubt. This, however, is
not the case with the other; the species in which organised bodies do
not appear, is in general so indurated or consolidated in its structure,
and changed in its position, that this common origin of those masses is
by good naturalists, who have also carefully examined them, actually
denied. Now, the secondary masses may be considered, not only as
intermediate with respect to its actual place, as M. Pallas has
represented it, but as uniting together the primary and tertiary, or as
participating of the distinguishing characters of the other two. It
is homologated with the primitive mountains, in the solidity of its
substance and in the position of its strata; with the tertiary species,
again, in its containing marks of organised bodies. How far this view
of things is consistent with the theory of the earth now given, is
submitted to the consideration of the unprejudiced.
Let us see what our learned author has said farther on this subject,
(page 65).
"Je dois parler d'un ordre de montagnes tres-certainement posterieur aux
couches marines, puisque celles-ci, generalement lui servent de base.
On n'a point jusqu'ici observe une suite de ces _montagnes tertiaires_,
effet des catastrophes les plus modernes de notre globe, si marquee
et si puissante, que celle qui accompagne la chaine Ouralique ou cote
occidentale fur tout la longueur. Cette suite de montagnes, pour la
plupart composees de grais, de marnes rougeatres, entremelees de couches
diversement mixtes, forme une chaine par-tout separee par une vallee
plus ou moins large de la bande de roche calcaire, dont nous avons
parle. Sillonnee et entrecoupee de frequens vallons, elles s'eleve
souvent a plus de cent toises perpendiculaires, se repand vers les
plaines de la Russie en trainees de collines, qui separent les rivieres,
en accompagnant generalement la rive boreale ou occidentale, et degenere
enfin en deserts sableux qui occupent de grands espaces, et s'etendent
surtout par longues bandes paralleles aux principales traces qui suivent
les cours des rivieres. La principale force de ces montagnes tertiaires
est plus pres de la chaine primitive par-tout le gouvernement
d'Orenbourg et la Permie, ou elle consiste principalement en grais, et
contient un fond inepuisable de mines de cuivre sableuses, argileuses,
et autres qui se voient ordinairement dans les couches horizontales.
Plus loin, vers la plaine, sont des suites de collines toutes marneuses,
qui abondent autant en pierres gypseuses, que les autres en minerais
cuivreux. Je n'entre pas dans le detail de celles-ci, qui indiquent
sur-tout les sources salines; mais je dois dire des premieres, qui
abondent le plus et dont les plus hautes elevations des plaines, meme
celle de Moscou, sont formees, qu'elles contiennent tres-peu de traces
de productions marines, et jamais des amas entiers de ces corps, tels
qu'une mer reposee pendant des siecles de suite a pu les accumuler dans
les bancs calcaires. Rien, au contraire, de plus abondant dans ces
montagnes de grais stratifie sur l'ancien plan calcaire, que des troncs
d'arbres entieres et des fragmens de bois petrifie, souvent mineralise
par le cuivre ou le fer; des impressions de troncs de palmires, de
tiges de plantes, de roseau, et de quelques fruits etrangers; enfin des
ossemens d'animaux terrestres, si rares dans les couches calcaires. Les
bois petrifies se trouvent jusques dans les collines de sable de la
plaine; l'on en tire, entr'autres, des hauteurs sablonneuses aux
environs de Sysran sur la Volga, changes en queux tres-fin, qui a
conserve jusqu'a la texture organique du bois, et remarquables sur-tout
par les traces tres-evidentes de ces vers rongeurs qui attaquent les
vaisseaux, les pilotis et autres bois trempes dans la mer, et qui sont
proprement originaires de la mer des Indes."
This philosopher has now given us a view of what, according to the
present fashion of mineral philosophy, he has termed _montagnes
primitives, secondaires, et tertiaires_. The first consists in masses
and strata, much indurated and consolidated, and greatly displaced in
their position; but the character of which is chiefly taken from this,
that they contain not any visible mark of animal or vegetable bodies.
The second are formed in a great measure of marine productions, are
often no less consolidated than those of the first class, and frequently
no less changed in their natural shape and situation.
The third again have for character, according to this learned theorist,
the containing of those organised bodies which are proper to the earth,
instead of those which in the second class had belonged to the sea;
in other respects, surely there is no essential difference. It is not
pretended that these tertiary strata had any other origin, than that of
having been deposited in water; it is not so much as suspected, that
this water had been any other than that of the sea; the few marine
bodies which M. Pallas here acknowledges, goes at least to prove this
fact: and with regard to the mineral operations which had been employed
in consolidating those water formed strata, it is impossible not to be
convinced that every effect visible in the other two are here also to be
perceived.
From this view of mineral bodies, taken from the extensive observations
of the Russian dominions, and from the suppositions of geologists in
relation to those appearances, we should be led to conclude that the
globe of this earth had been originally nothing but an ocean, a world
containing neither plant nor animal to live, to grow and propagate its
species. In following a system founded on those appearances, we must
next suppose, that to the sterile unorganised world there had succeeded
an ocean stored with fish of every species. Here it would be proper to
inquire what sustained those aquatic animals; for, in such a system as
this, there is no provision made for continuing the life even of the
individuals, far less of feeding the species while, in an almost
infinite succession of individuals, they should form a continent of land
almost composed of their _exuviae_.
If fish can be fed upon water and stone; if siliceous bodies can, by
the digesting powers of animals, be converted into argillaceous and
calcareous earths; and if inflammable matter can be prepared without the
intervention of vegetable bodies, we might erect a system in which this
should be the natural order of things. But to form a system in direct
opposition to every order of nature that we know, merely because we may
suppose another order of things different from the laws of nature which
we observe, would be as inconsistent with the rules of reasoning in
science, by which the speculations of philosophy are directed, as it
would be contrary to common sense, by which the affairs of mankind are
conducted.
Still, however, to pursue our visionary system, after a continent had
been formed from the relicts of those animals, living, growing, and
propagating, during an indefinite series of ages, plants at last are
formed; and, what is no less wonderful, those animals which had formed
the earth then disappear; but, in compensation, we are to suppose, I
presume, that terrestrial animals began. Let us now reason from those
facts, without either constraining nature, which we know, or forming
visionary systems, with regard to things which are unknown. It would
appear, that at one period of time, or in one place, the matter of the
globe may be deposited, in strata, without containing any organised
bodies; at another time, or in another place, much animal matter may be
deposited in strata, without any vegetable substance there appearing;
but at another period, or at another time, strata may be formed with
much vegetable matter, while there is hardly to be observed any animal
body. What then are we to conclude upon the whole? That nature, forming
strata, is subject to vicissitudes; and that it is not always the same
regular operation with respect to the materials, although always forming
strata upon the same principles. Consequently, upon the same spot in
the sea, different materials may be accumulated at different periods of
time, and, conversely, the same or similar materials may be collected in
different places at the same time. Nothing more follows strictly from
the facts on which we now are reasoning; and this is a conclusion which
will be verified by every appearance, so far as I know.
Of this I am certain, that in a very little space of this country, in
many places, such a course of things is to be perceived. Nothing so
common as to find alternated, over and over again, beds of sand-stone
without animal bodies, beds of coal and schistus abounding with
vegetable bodies, beds of lime-stone formed of shells and corals, and
beds or particular strata of iron-stone containing sometimes vegetable
sometimes animal bodies, or both. Here, indeed, the strata are most
commonly inclined; it is seldom they are horizontal; consequently, as
across the whole country, all the strata come up to the day, and may be
seen in the beds of our rivers, we have an opportunity of observing that
great variety which is in nature, and which we are not able to explain.
This only is certain, from what we see, that there is nothing formed
in one epoch of nature, but what has been repeated in another, however
dissimilar may be the operations which had intervened between those
several epochs.
It must not be alleged, that the heights of the Oural mountains, or the
hardness of their rocks, make an essential distinction between them
and the argillaceous or arenaceous strata of the plains; solidity and
hardness, as well as changes in their height and natural position, has
been superinduced in operations posterior to the collection of those
masses,--operations which may be formed in various degrees, even in the
different parts of the same mass. If this is the case, there can be no
difficulty in conceiving a stratum, which appears to be argillaceous
or marly in the plains, to be found jasper in the Oural mountains. But
there is nothing in the Oural mountains, that may not be found some
where or other in the plains, although the soft and easily decomposing
argillaceous strata be not found upon the Oural mountains, or the Alps,
for this reason, that had those mountains been formed of such materials,
there had not been a mountain there at this day.
But surely the greatest possible error, with regard to the philosophy of
this earth, would be to confound the sediment of a river with the strata
of the globe; bodies deposited upon the surface of the earth, with those
sunk at the bottom of the sea; and things which only form the travelled
or transported soil, with those which constitute the substratum or the
solid earth. How far M. Pallas has committed this oversight, I leave
others to determine. After mentioning those strata in which wood is
found petrified, and metallic minerals formed, he thus proceeds, (page
69).
"Dans ces memes depots sableux et souvent limoneux, gisent les restes
des grands animaux de l'Inde: ces ossemens d'elephans, de rhinoceros, de
buffles monstrueux, dont on deterre tous les jours un si grand nombre,
et qui font l'admiration des curieux. En Siberie, ou l'on a decouvert le
long de presque toutes les rivieres ces restes d'animaux etrangers,
et l'ivoire meme bien conserve en si grande abondance, qu'il forme un
article de commerce, en Siberie, dis je, c'est aussi la couche la plus
moderne de limon sablonneux qui leur sert de sepulture, et nulle part
ces monumens etrangers sont si frequens, qu'aux endroits ou la grande
chaine, qui domine surtout la frontiere meridionale de la Siberie, offre
quelque depression, quelque ouverture considerable.
"Ces grands ossemens, tantot epars tantot entasses par squelettes,
et meme par hecatombes, consideree dans leurs sites naturels, m'ont
sur-tout convaincu de la realite d'un deluge arrive sur notre terre,
d'une catastrophe, dont j'avoue n'avoir pu concevoir la vraisemblance
avant d'avoir parcouru ces places, et vu, par moi-meme, tout ce qui peut
y servir de preuve a cet evenement memorable[24]. Une infinite de ces
ossemens couches dans des lits meles de petites tellines calcinees, d'os
de poissons, de glossopetres, de bois charges d'ocre, etc. prouve deja
qu'ils ont ete transportes par des inondations. Mais la carcasse d'un
rhinoceros, trouve avec sa peau entiere, des restes de tendons, de
ligamens, et de cartilages, dans les terres glacees des bords du
Viloui, dont j'ai depose les parties les mieux conservees au cabinet de
l'Academie, forme encore une preuve convaincante que ce devait etre
un mouvement d'inondation des plus violens et des plus rapides, qui
entraina jadis ces cadavres vers nos climats glaces, avant que la
corruption eut le tems, d'en detruire les parties molles. Il seroit a
souhaiter qu'un observateur parvint aux montagnes qui occupent l'espace
entre les fleuves Indighirka et Koylma ou selon le rapport des
chasseurs, de semblables carcasses d'elephans et d'autres animaux
gigantesques encore revetues de leurs peaux, ont ete remarquees a
plusieurs reprises."
[Note 24: Voyez le Memoire, imprime dans le XVII. volume des nouveaux
Commentaires de l'Academie Imperiale de Petersbourgh.]
The question here turns upon this, Are the sea shells and glossopetrae,
which are thus found deposited along with those skeletons, in their
natural state, or are they petrified and mineralised. If the productions
of the sea shall here be found collected along with bodies belonging to
the surface of the earth, and which had never been within the limits of
the sea, this would surely announce to us some strange catastrophe,
of which it would be difficult, perhaps, to form a notion; if, on the
contrary, those marine productions belong to the solid strata of the
earth, in the resolution or decay of which they had been set at liberty,
and were transported in the floods, our author would have no reason from
those appearances to conclude, there had existed any other deluge than
those produced by the waters of the land[25].
[Note 25: Since writing this, I find my doubts in a great measure
resolved, in reading M. Pallas's Journal, translated from the German by
M. Gauthier de la Peyronie. What I had suspected is, I think, confirmed
in the distinct account which M. Pallas has given of those occasions
in which the bones of land animals and marine objects are found buried
together. The marine objects are mineralised; consequently, they have
proceeded from the decomposition of the solid strata; and, having been
travelled in the running water of the surface of the earth, they must
have been deposited in those beds of rivers, which now are dry, alongst
with the bones, or the entire bodies of terrestrial animals, the remains
of which are now found there. This argument, from the state of those
marine bodies will not be allowed, perhaps by the generality of
mineralists, who attribute to the operations of water every species of
petrifaction or mineralisation; but, until some species of proof be
given with regard to the truth of that theory, which vulgar error first
suggested, I must reason from a theory, in proof of which I have given
clear examples, and, I think, irrefragable arguments, which shall be
more and more illustrated. Thus may be removed the necessity of a
general deluge, or any great catastrophe, in order to bring together
things so foreign to each other; but at the same time we would ascertain
this fact, That formerly the Elephant and Rhinoceros had lived in
Siberia. (See Voyage de Pallas, Tom. II. p. 377 and 403.)]
Having thus endeavoured to remove this prevailing prejudice, of there
being primitive parts in this earth, parts of which the composition and
constitution are not to be explained upon the principles of natural
philosophy, it will be proper to inquire, how far there may be in the
theory, which has now been given, principles by which may be explained
those appearances that have led natural philosophers to form
conclusions, of there being in this earth parts whose origin may not be
traced; and of there being parts whose origin may not be explained upon
the same principles which apply so well to all the rest.
CHAP. V.
Concerning that which may be termed the Primary Part of the Present
Earth.
In the present theory, it is maintained, that there is no part of the
earth which has not had the same origin, so far as this consists in that
earth being collected at the bottom of the sea, and afterwards produced,
as land, along with masses of melted substances, by the operation of
mineral causes. But, though all those things be similar, or equal, as to
the manner of their production, they are far from being so with regard
to the periods of their original composition, or to the subsequent
operations which they may have undergone.
There is a certain order established for the progress of nature, for the
succession of things, and for the circulation of matter upon the surface
of this globe; and, the order of time is associated with this change of
things. But it is not in equal portions that time is thus combined with
dissimilar things, nor always found, in our estimation, as equally
accompanying those which we reckon similar. The succession of light and
darkness is that which, in those operations, appears to us most steady;
the alternation of heat and cold comes next, but not with equal
regularity in its periods. The succession of wet and dry upon the
surface of the earth, though equally the work of nature and the effect
of regular causes, is often to us irregular, when we look for equal
periods in the course of things which are unequal. It is by equalities
that we find order in things, and we wish to find order every where.
The present object of our contemplation is the alternation of land
and water upon the surface of this globe. It is only in knowing this
succession of things, that natural appearances can be explained; and
it is only from the examination of those appearances, that any certain
knowledge of this operation is to be obtained. But how shall we acquire
the knowledge of a system calculated for millions, not of years only,
nor of the ages of man, but of the races of men, and the successions of
empires? There is no question here with regard to the memory of man, of
any human record, which continues the memory of man from age to age; we
must read the transactions of time past, in the present state of natural
bodies; and, for the reading of this character, we have nothing but
the laws of nature, established in the science of man by his inductive
reasoning.
It has been in reasoning after this manner, that I have endeavoured to
prove, that every thing which we now behold, of the solid parts of this
earth, had been formerly at the bottom of the sea; and that there is, in
the constitution of this globe, a power for interchanging sea and land.
If this shall be admitted as a just view of the system of this globe,
we may next examine, how far there are to be found any marks of certain
parts of our earth having more than once undergone that change of
posture, or vicissitude of things, and of having had reiterated
operations of the mineral kingdom changing their substance, as well as
altering their positions in relation to the atmosphere and sea.
Besides the gradual decay of solid land, exposed to the silent
influences of the atmosphere, and to the violent operations of the
waters moving upon the surface of the earth, there is a more sudden
destruction that may be supposed to happen sometimes to our continents
of land. In order to see this, it must be considered, that the
continents of our earth are only raised above the level of the sea by
the expansion of matter, placed below that land, and rarified in that
place: We may thus consider our land as placed upon pillars, which may
break, and thus restore the ancient situation of things when this land
had been originally collected at the bottom of the ocean. It is not here
inquired by what mechanism this operation is to be performed; it is
certainly by the exertion of a subterranean power that the land is
elevated from the place in which it had been formed; and nothing is more
natural than to suppose the supports of the land in time to fail, or be
destroyed in the course of mineral operations which are to us unknown.
In that case, whatever were remaining of that land, which had for
millions of ages past sustained plants and animals, would again be
placed at the bottom of the sea; and strata of every different species
might be deposited again upon that mass, which, from an atmospheric
situation, is now supposed to be lower than the surface of the sea.
Such a compound mass might be again resuscitated, or restored with the
new superincumbent strata, consolidated in their texture and inclined in
their position. In that case, the inferior mass must have undergone a
double course of mineral changes and displacement; consequently, the
effect of subterranean heat or fusion must be more apparent in this
mass, and the marks of its original formation more and more obliterated.
If, in examining our land, we shall find a mass of matter which had been
evidently formed originally in the ordinary manner of stratification,
but which is now extremely distorted in its structure, and displaced in
its position,--which is also extremely consolidated in its mass, and
variously changed in its composition,--which therefore has the marks
of its original or marine composition extremely obliterated, and many
subsequent veins of melted mineral matter interjected; we should then
reason to suppose that here were masses of matter which, though not
different in their origin from those that are gradually deposited at the
bottom of the ocean, have been more acted upon by subterranean heat and
the expanding power, that is to say, have been changed in a greater
degree by the operations of the mineral region. If this conclusion shall
be thought reasonable, then here is an explanation of all the peculiar
appearances of the alpine schistus masses of our land, those parts which
have been erroneously considered as primitive in the constitution of the
earth.
We are thus led to suppose, that some parts of our earth may have
undergone the vicissitudes of sea and land more than once, having been
changed from the summit of a continent to the bottom of the sea, and
again erected, with the rest of that bottom, into the place of land. In
that case, appearances might be found to induce natural philosophers to
conclude that there were in our land primary parts, which had not the
marine origin which is generally to be acknowledged in the structure
of this earth; and, by finding other masses, of marine origin,
superincumbent upon those primary mountains, they might make strange
suppositions in order to explain those natural appearances.
Let us now see what has been advanced by those philosophers who, though
they term these parts of the earth _primordial_, and not _primitive_, at
the same time appear to deny to those parts an origin analogous to that
of their secondary mountains, or strata that are aquiform in their
construction.
M. de Luc, after having long believed that the strata of the Alps had
been formed like those of the low countries, at the bottom of the sea,
gives an account of the occasion by which he was first confirmed in the
opposite opinion.[26] Like a true philosopher, he gives us the reason of
this change.
[Note 26: Lettres Physique et Morales sur l'Histoire de la Terre, tom.
2. pag. 206.]
"Ce fut une espece de _montagne_ tres commune, et que j'avois souvent
examinee qui dessilla mes yeux. La pierre qui la compose est de
la classe appellee _schiste_; son caractere generique est d'etre
_feuilletee_; elle renferme _l'ardoise_ dont on couvre les toits. Ces
_feuillets_ minces, qu'on peut prendre pour des _couches_, et qui le
font en effet dans quelques pierres de ce genre, rappelloient toujours
l'idee vague de depots des eaux. Mais il y a des masses dont la
composition est plutot par fibres que par feuillets, et dont le moellon
ressemble aux copeaux de bois d'un chantier. Le plus souvent aussi les
feuillets sont situes en toute suite de sens dans une meme _montagne_,
et quelquefois meme verticalement, Enfin il s'en trouve de si tortilles,
qu'il est impossible de les regarder comme des depots de l'eau.
"Ce fut donc cette espece de montagne qui me persuada la premiere
que toutes les montagnes n'avoient pas une meme origine. Le lieu ou
j'abjurai mon erreur, etoit un de ces grands _chantiers_ petrifies, qui,
par la variete du tortillement, et des zig-zags des fibres du moellon
qui le composoit, attira singulierement mon attention. C'etoit un sort
grand talus qui venoit d'une face escarpee; j'y montai pour m'approcher
du rocher, et je remarquai, avec etonnement, des multitudes de paquets
enchevetres les uns dans les autres, sans ordre ni direction fixe; les
uns presqu'en rouleaux; les autres en zig-zag; et meme ce qui, separe de
la montagne, eut peu etre pris pour des _couches_, le trouvoit incline
de toute maniere dans cette meme face de rocher. _Non_, me dis-je alors
a moi-meme; _non, l'eau n'a pu faire cette montagne.... Ni celle-la
donc_, ajoutai-je en regardant ailleurs.... _Et pourquoi mieux celle-la?
Pourquoi toutes les montagnes devroient-elles etre le produit des eaux,
seulement parce qu'il y en a quelques-unes qui annoncent cette origine_?
En effet, puis qu'on n'a songe aux eaux, comme cause des montagnes,
que par les preuves evidentes que quelques-unes offroient de cette
formation; pourquoi etendre cette consequence a toutes, s'il y en
a beaucoup qui manquent de ces caracteres? C'est comme le dit Mr.
d'Alembert, qu'on generalise ses premieres remarques l'instant d'apres
qu'on ne remarquoit rien."
Science is indebted to this author for giving us so clear a picture
of natural appearances, and of his own reasoning upon those facts, in
forming his opinion; he thus leads astray no person of sound judgment,
although he may be in error. The disposition of things in the present
case are such, that, reasoning from his principles, this author could
not see the truth; because he had not been persuaded, that aquiform
strata could have been so changed by the chemical power of fusion, and
the mechanical force of bending while in a certain state of softness.
But though, in this case, the reasoning of this philosopher is to be
justified, so far as he proceeded upon principles which could not lead
him to the truth, his conduct is not so irreproachable in applying them
to cases by which their fallacy might have been detected. This author
acknowledges calcareous strata to be aquiform in their original; but,
in those mountains which he has so much examined, he will find those
aquiform bodies have undergone the same species of changes, which made
him conclude that those schistus mountains had not been truly aquiform,
as he at first had thought them. This would have led him to reason back
upon his principles, and to say, _If one species of strata may be thus
changed in its texture, and its shape, may not another be equally so?
Therefore, may not the origin of both be similar_?
But least I should do injustice to this author, to whom we are indebted
for many valuable observations in natural history, I shall transcribe
what he has said upon the subject, being persuaded that my readers will
not think this improper in me, or impertinent to the argument.
"Quand nous fumes une fois persuades que la mer n'avoit pas fait
toutes les _montagnes_, nous entreprimes de decouvrir les caracteres
distinctifs de celles qui lui devoient leur origine; et s'il etoit, par
exemple, des matieres qui leur fussent propres. Mais nous y trouvames
les memes difficultes qu'on rencontre dans tout ce qu'on veut classer
dans la nature. On peut bien distinguer entr'elles les choses qui
ont fortement l'empreinte de leur classe; mais les confins echappent
toujours.
"C'est la, pour le dire en passant, ce qui a pu conduire quelques
philosophes a imaginer cette _chaine des etres_ ou ils supposent,
que, de la pierre a l'homme et plus haut, les nuances sont reellement
imperceptibles. Comme si, quoique les limites soyent cachees a nos sens,
notre intelligence ne nous disoit pas, qu'il y a un _saut_, une distance
meme infinie, entre le plus petit degre d'organization _propageante_,
et la matiere unie par la simple cohesion: entre le plus petit degre de
_sensibilite_, et la matiere insensible: entre la plus petite capacite
d'observer et de transmettre ses observations, et l'instinct constamment
le meme dans l'espece. Toutes ces differences tranchees existent dans la
nature; mais notre incapacite de rien connoitre a fond, et la necessite
ou nous sommes de juger de tout sur des apparences, nous fait perdre
presque toutes les limites, parce que sur ces bords, la plupart des
phenomenes sont equivoques. Ainsi la plante nous paroit se rapprocher de
la pierre, mais n'en approche jamais reellement.
"On eprouve la meme difficulte a classer les montagnes; et quoique
depuis quelque tems plusieurs naturalistes ayent aussi observe qu'elles
n'ont pas toutes la meme origine, je ne vois pas qu'on soit parvenu a
fixer des caracteres infaillibles, pour les placer surement toutes dans
leurs classes particulieres.
"Apres avoir examine attentivement cet objet, d'apres les phenomenes que
j'ai moi-meme observes, et ce que j'ai appris par les observations des
autres; j'ai vu que c'etoit la un champ tres vaste, quand on vouloit
l'embrasser en entier, et trop vaste pour moi, qui n'etoit pas libre d'y
consacrer tout le tems qu'il exige. Je me suis donc replie sur mon objet
principal, savoir _la cause qui a laisse des depouilles marines dans nos
continens_, et l'examen des hypotheses sur cette matiere.
"Les phenomenes ainsi limites, se reduisent a ceci: qu'il y a dans nos
continens des montagnes visiblement formees par des _depots successifs
de la mer_ et a l'egard des quelles il n'y a besoin de rien imaginer, si
ce n'est la maniere dont elles en sont sorties: qu'il y en a d'autres au
contraire, qui ne portent aucun des caracteres de cette cause, et qui,
si elles ont ete produites dans la _mer_, doivent etre l'effet de toute
autre cause que de simples depots successifs, et avoir meme precede
l'existence des animaux marins. J'abandonne donc les classes confuses
ou ces caracteres sont equivoques, jusqu'a ce qu'elles servent a fonder
quelque hypothese; ayant assez de ces deux classes tres distinctes pour
examiner d'apres elles tous les systemes qui me sont connus.
"La ou ces deux classes de montagnes sont melees, on remarque que celles
qui sont formees par _couches_, et qui renferment des _corps marins_,
recouvrent souvent celles de l'autre classe, mais n'en sont jamais
recouvertes. On a donc naturellement conclu, que lors meme que la _mer_
auroit en quelque part a la formation des montagnes ou l'on ne reconnoit
pas son caractere, celles auxquelles elle a travaille seule, en enlevant
des matieres dans certaines parties de son fond et les deposant dans
d'autres, font au moins les dernieres formees. On les a donc nommees
_secondaires_, et les autres _primitives_.
"J'adopterai la premiere de ces expressions; car c'est la meme qui nous
etoit venu a l'esprit a mon frere, et a moi longtemps avant que nous
l'eussions vue employer; mais je substituerai celle de _primordiales a_
_primitives_ pour l'autre classe de _montagnes_, afin de ne rien decider
sur leur origine. Il est des _montagnes_, dont jusqu'a present on n'a pu
demeler la cause: voila le fait. Je ne dirai donc pas qu'elles ont
ete creees ainsi, parce qu'en physique je ne dois pas employer des
expressions sur lesquelles on ne s'entend pas. Sans doute cependant,
que l'histoire naturelle ni la physique ne nous conduisent nullement a
croire que notre globe ait existe de toute eternite; et lorsqu'il prit
naissance, il fallut bien que la matiere qui le composa fut de quelque
nature, ou sous quelque premiere forme integrante. Rien donc jusqu'ici
n'empeche d'admettre que ces _montagnes_ que je nommerai _primordiales_,
ne soient reellement _primitives_; je penche meme pour cette opinion
a l'egard de quelques unes. Mais il y a une tres grande variete
entr'elles; et quoiqu'elles soyent toutes egalement exclues de la classe
_secondaire_, elles ne sont pas toutes semblables: il y en a meme un
grand nombre dont les matieres ont une certaine configuration qui semble
annoncer qu'elles ayent ete molles et durcies ensuite, quoique par
une toute autre cause que celle qui a agi pour former les montagnes
secondaires."
Here I would beg leave to call the attention of philosophers to this
observation of a naturalist who explains all petrification, and the
consolidation of strata by aqueous infiltration. If he has here found
reason to conclude that, in those primordial parts of the earth, there
are a great number which, from their present configuration, must have
been in a soft state and then hardened, and this by a quite different
cause from that which he supposes had produced the consolidation and
hardness of the secondary parts; this is entering precisely into my
views of the subject, in ascribing all the consolidation of the earth,
whether primary or secondary, to one general cause, and in tracing this
cause, from its effects, to be no other than the fusion of those bodies.
It must be evident, that if this philosopher has seen good reason for
concluding such a softening cause, which had operated upon the primary
parts, to be quite different from that which he ascribes to the
consolidation of the secondary, which is the effect of water, it must
then, I say, be evident that the softening cause of the primary parts,
if not heat, by which every degree of fusion may be produced, must be an
occult cause, one which cannot be admitted into natural philosophy.
By thus choosing to consider mountains as of two distinct kinds, one
aquiform which is understood, and the other primordial which is not to
be known, we supersede the necessity of reconciling a theory with many
appearances in nature which otherwise might be extremely inconvenient
to our explanation, if not inconsistent with our system. Our author no
doubt has thus relieved himself from a considerable difficulty in the
philosophy of this earth, by saying here is a great part which is not
to be explained. But I would beg leave to observe, that this form of
discussion, with regard to a physical subject, is but a mere confession
of our ignorance, and has no tendency to clear up another part of the
subject of which one treats, however it may impress us with a favourable
opinion of the theorist, in allowing him all the candour of the
acknowledgement.
The general result of the reasoning which we now have quoted, and what
follows in his examination, seems to terminate in this; that there are
various different compositions of mountains which this author cannot
allow to be the production of the sea; but it is not upon account of
the matter of which they are formed, or of the particular mixture and
composition of those species of matter, of which the variety is almost
indefinite. According to this philosopher, the distinction that we are
to make of those primordial and secondary competitions, consists in
this, that the first are in such a shape and structure as cannot be
conceived to be formed by subsidence in water.
M. de Saussure has carefully examined those same objects; and he seems
inclined to think that they must have been the operation of the ocean;
not in the common manner of depositing strata, but in some other way by
crystallization. The present theory supposes all those masses formed
originally in the ordinary manner, by the deposits or subsidence
of materials transported in the waters, and that those strata were
afterwards changed by operations proper to the mineral regions.
But the subject of the present investigation goes farther, by inquiring
if, in the operations of the globe, a primary and secondary class of
bodies may be distinguished, so far as the one may have undergone the
operations of the globe, or the vicissitudes of sea and land, oftener
than the other, consequently must be anterior to the later productions
both in time and operation, although the original of all those bodies
be the same, and the operations of the earth, so far as we see in the
effects, always proceed upon the same principles. This is an extensive
view of nature to which few have turned their thoughts. But this is
a subject to which the observations described by this author have
evidently a reference.
In his 113th letter, he has given us a view of one of those parts of the
earth that are proper to be examined in determining this question so
important in the genealogy of land, although no ways concerned in
altering the principles upon which nature in forming continents must
proceed.
It is in describing the nature of the mountains about _Elbingerode_; and
he begins in ascending from Hefeld.
"Cette partie exterieure de la chaine est _primordiale_: c'est du
_granit_ a _Hereld_ et au commencement de la route; puis quand on passe
dans d'autres vallees, on trouve les _schistes_ et la _roche grise_ dans
tout le pied des montagnes: mais des qu'on est arrive a une certain
hauteur, on voit de la _pierre a chaux_ par couches etendue sur ces
matieres; et c'est elle qui forme le sommet de ces memes montagnes;
tellement que la plaine elevee, qui conduit a _Elbingerode_, est
entierement de _pierre a chaux_, excepte dans sa partie la plus haute ou
cette pierre est recouverte des memes _gres_ et sables _vitrescibles_
qui sont sur le schiste du Bruchberg et sur la _pierre a chaux_ dans la
_Hesse_ et le pays de Gottingue.
"Les environs d'Elbingerode etant plus bas que ces parties recouvertes
de matieres vitrescibles, montrent la _pierre a chaux_ a nud; et l'on y
trouve de tres beaux marbres, dont les nuances jaunes, rouges et vertes
sont souvent tres vives, et embellies par les coupes des _corps marins_.
"Cependant le schiste n'est pas enseveli partout sous ces depots de la
mer; on le retrouve en quelques endroits, et meme avec de _filons_.
"Ainsi au milieu de ces matieres _calcaires_ qui forment le sol montueux
des environs _d'Elbingerode_, paroit encore le _schiste_ sur lequel
elles ont ete deposees: Et en montant a la partie la plus elevee de
ces memes environs, on trouve que la _pierre a chaux_ est recouverte
elle-meme d'une _pierre sableuse_ grise par couches, dans laquelle on
voit quantite de petits fragmens de _schiste_ poses de plat. C'est la
que se trouve une des mines de _fer_ dont le minerai va en partie a la
_Koningshutte_, mais en plus grande partie a la _Rothechutte_, qui n'est
qu'a une lieue de distance. On perce d'abord la couche sableuse; sous
elle se trouve de la _pierre a chaux_ grise; puis une couche de
_pierre a chaux ferrugineuse_, remplie de _corps marins_, et surtout
_d'entroques_: C'est cette _couche_ qui est ici le _minerai_; et elle
appartient a la formation de cette eminence comme toutes les autres
_couches_. Cette mine se nomme _bomshey_: elle n'est pas riche; mais
elle sert de _fondant_ aux matieres ferrugineuses tirees des filons des
montagnes primordiales en meme tems qu'elle leur ajoute son _fer_ dans
la fonte. A quelque distance de la on a perce un autre puits; qui a
transverse d'abord une sorte de pierre, que je ne saurois nommer, mais
qui ressemble fort a une _lave_ poreuse. Au dessous de cette couche on a
retrouve la _pierre a chaux_ ordinaire; puis la _couche ferrugineuse_ y
continue; mais elle differe un peu de ce qu'elle est dans l'autre mine,
une partie de sa substance etant convertie en _jaspe_.
"Mais ce qui est digne de la plus grande attention dans cette contree,
est un filon peu distant nomme _Buchenberg_, qui appartient en partie au
Roi, et en partie a Mr. le Comte de _Wernigerode_. La montagne en cette
endroit montre une vallee artificielle de 70 a 80 pieds de profondeur,
de 20 a 30 de largeur dans le haut, et de 400 toises en etendue. C'est
le creusement qu'on a deja fait en suivant ce _filon_ de _fer_, que l'on
continue a exploiter de la meme maniere sur les terres de Mr. le Comte
de _Wernigerode_. La matiere propre de la montagne _est_ de _schiste_;
et la vallee qui se forme de nouveau a mesure qu'on enleve la _gangue_
du _filon_, a surement deja existe dans la mer sous la forme d'une
_fente_, qui a ete remplie, et en particulier des ingrediens dont on
fait aujourd'hui le _fer_."
Here is a supposition of our author that corresponds to nothing which
has yet been observed any where else, so far as I know. It is concerning
a mineral vein, one which does not appear to differ in any respect from
other mineral veins, except in being worked in that open manner which
has given our author an idea of its being a valley. He then supposes
that valley (or rather empty vein) to have been in this mountain when at
the bottom of the sea, and that this mineral vein had then been filled
with those materials which now are found in that space between the two
sides of the separated rock. This is a very different operation from
that of infiltration, which is commonly supposed to be the method of
filling mineral veins; but, we shall soon see the reason why our author
has here deserted the common hypothesis, and has adopted another to
serve the occasion, without appearing to have considered how perfectly
inconsistent those two suppositions are to each other. That mineral
veins have been filled with matter in a fluid state, is acknowledged by
every body who has either looked at a mineral vein in the earth, or in a
cabinet specimen; mineralists and geologists, in general, suppose this
to have been done by means of solutions and concretions, a supposition
by no means warranted by appearances, which, on the contrary, in general
demonstrate that the materials of those veins had been introduced in the
fluid state of fusion. But here is a new idea with regard to the filling
of those veins; and, I would now beg the reader's attention to the facts
which follow in this interesting description, and which have suggested
that idea to our author.
"Quand cette matiere accidentelle est enlevee, on voit la coupe du
_schiste_ des deux cotes de la _fente_, faisant un _toit_ et un _mur_,
parce que la _fente_ n'est pas absolument verticale: des qu'il y a
un peu d'inclinaison, on distingue un _toit_ et un mur, comme j'ai
l'honneur de l'expliquer a V.M. On ne connoit point encore l'etendue de
ce filon, ni dans sa profondeur, ou l'on ne peut pas s'enfoncer beaucoup
de cette maniere, ni dans la longueur, selon laquelle on continue a
l'exploiter.
"Voila donc un _filon_, a la rigueur de la definition que j'en ai donne
a V.M. c'est a dire, une _fente_ dans la montagne naturelle, _comblee_
de _matiere_ etrangere. Mais ce qu'il y a d'extraordinaire ici, c'est
que cette _matiere_ vient de la _mer_: ce sont differentes _couches
aquiformes_, dont quelques unes sont remplies de _corps marins_. Il y
a des _couches_ d'une _terre martiale_ fort brune et sans liaison:
d'autres, au contraire toujours _martiales_, sont tres dures et
renferment de tres beau jaspe sanguin: d'autres enfin sont de vrai
_marbre_ gris veinees de rouge. C'est dans ce marbre que font les _corps
marins_, savoir des coquillages et des spongites; et il est lui-meme
martial comme tout le reste: les mineurs le nomment _Kubrimen_, et ne
l'employent que comme un _fondant_ pour d'autres _mineraux de fer_.
"A ce _filon_, s'en joignent d'autres plus embarrassans. Ils viennent du
_toit_, qu'ils divisent par de larges _fentes_ comblees, aboutissantes
au _filon_ principale. Ils font de meme _calcaires_ et marins faits par
_couches_; mais ces _couches_ ont une si grande inclinaison, que je ne
puis les comprendre: il faut qu'il y ait eu d'etranges bouleversemens
dans ces endroits-la[27].
[Note 27: Here, no doubt, are appearances which it is impossible to
explain by the theory of infiltration; it is the filling of mineral
veins, and their branches or ramifications, with marble containing marks
of marine objects. But, if we shall suppose this marble to have been in
the fluid state of fusion, as well as the iron-ore and jasper, we may
easily conceive it introduced into the principal vein and its branches.
The description here given of those appearances is by no means such as
to enable us to judge particularly of this case, which surely merits the
most accurate investigation, and which, I doubt not, will give physical
demonstration of the fusion of those mineral substances. I know that
shells have been found within the body of veins in Germany; but, a
stratification of those materials in a vein was never heard of before,
so far as I know.]
"Ces _fentes_ se sont faites, et ont ete remplies, dans la _mer_;
puisque les matieres qui les remplissent sont de la classe de ses depots
tres connoissables, et qu'il contiennent des _depouilles marines_. Mais
ce qui embarrasse alors c'est que les autres _filons_ ne soyent pas dans
le meme cas. N'est ce point la encore un indice, que ces _fentes_ out
ete d'abord et principalement remplies de matieres, poussees du fond par
la meme force qui secouoit les montagnes[28].
[Note 28: But what is this power by which matter is to be forced from
the bottom of the sea to the top of the mountains? For, unless we can
form some idea of that power which, as a cause, we ascribe to the
perceived effect, we either say nothing to the purpose, or we employ a
preternatural cause. It is not sufficient to imagine a power capable of
raising from the bottom of the sea the materials deposited in the abyss;
it is also necessary to find a power capable of softening bodies which
are hard, and of thus consolidating those masses which are formed of
loose or unconnected materials. Such a power, indeed, the present theory
assumes; and, so far as this shall be implied in the supposition of our
author, it will thus have received a certain conformation.]
"Ce _filon_ n'est pas le seul dans le _Hartz_ qui donne des signes
_marins_. Il y en a un autre, qui meme se rapproche davantage de
la nature du commun des _filons_, et ou l'on trouve aussi des
_coquillages_. C'est celui de _Haus-Hartzbergerzug_, pres de
_Clausthal_, ou, dans les _Halles_ de quelques mines de plomb
abandonnees, et dans une forte _d'ardoise_, on trouve de petites
_moules_ ou _tellines_ striees, d'une espece particuliere que j'ai vue
dans des _ardoises secondaires d'Arotzen_ en _Waldek_ et de _Sombernon_
en _Bourgogne_. Il y a donc certainement quelques _filons_ faits par les
depots de la _mer_ dans les _fentes_ de montagnes _primordiales_; comme
au contraire il y a des _filons_ metalliques sans indices _marins_,
dans des montagnes evidemment _secondaires_, telles que celles de
_Derbyshire_, ou les _filons_ de _plomb_ traversent des couches de
_pierre a chaux_."
Here again our author seems to me to refute his own supposition, That a
chasm in the schistus rock may have existed at the bottom of the sea,
and been then filled from above with such materials as were transported
by the moving water to that place, is not impossible; but nobody, who
knows the nature of a common metallic vein, can ever suppose it to have
been filled in that manner. Our author then adds, "On ne fait reellement
que commencer dans ce genre d'observations, considerees quant a la
Cosmologie; ainsi il ne faut point desesperer que tout cela ne se
devoile un jour, et que nous n'acquerrions ainsi un peu plus de
connoissance sur ce qui se passoit dans la _mer ancienne_.
"En revenant vers _Elbingerode_, nous retrouvames ces _schistes_, qui
paroissent au travers des _marbres:_ ils sont donc la continuation de la
masse _schisteuse_ a laquelle appartient le _filon_, dont je viens de
parler. Ce _filon_ a ete forme dans une _fente_, restee ouverte et vide:
les depots de la _mer_ l'ont comblee, en meme tems qu'ils formoient
les couches de _marbre_, qui sont a l'exterieur. En effet, ce _filon_
contient des _couches marines ferrugineuses_, de la meme nature que
celles des collines calcaires voisines formees sur le schiste.
"Nous partimes _d'Elbingerode_ dans l'apres midi pour nous rapprocher
de Clausthal. Notre chemin fut encore quelque tems sur des sommites
_calcaires_; et avant que d'en sortir, nous trouvames une autre mine
singuliere a _Arenfeld_. C'est encore un vrai _filon_; mais dans une
montagne de _pierre a chaux:_ C'est a-dire, que cette montagne a aussi
ete _fendue_, et que la _fente_ a ete remplie d'une _gangue_. La matiere
de ce _filon_ est encore _calcaire_ en plus grande partie; mais
cette _pierre a chaux_ distincte est _ferrugineuse_, et parsemee de
concretions de _jaspe_ comme celles _d'Elbingerode:_ on y trouve aussi
une matiere verdatre, qui, comme le _jaspe_, ne fait pas effervescence
avec l'eau forte."
Here is a phenomenon which is altogether incompatible with the theory
that this author has given us for the explanation of those appearances.
He supposes empty crevices in the schistus mountains at the bottom of
the sea; these crevices he supposes filled by the deposits of the sea,
at the same time, and with the same materials with which the lime-stone
strata were formed above the schistus mountains; but we find one of
those same veins in these secondary calcareous strata. Now, tho' we
should be disposed to allow, that, in the primordial mountain, of which
we are supposed not to know the origin, there might have been empty
crevices which were afterwards filled with materials transported by the
sea, this cannot be admitted as taking place in the loose or incoherent
materials deposited above the schistus. Consequently, this theory of our
author, which is evidently erroneous with regard to the veins in the
lime-stone, must, in the other case, be at least examined with a jealous
eye.
"Le haut de cette partie des montagnes _calcaires_ etoit encore
recouvert de _sable_ et de gres _vitrescibles_: et continuant a marcher,
sans aucune inflexion sensible, nous nous trouvames subitement sur les
_schistes_; d'ou nous montames plus rapidement. Puis traversant quelques
petites vallees nous arrivames sur les montagnes qui appartiennent au
prolongement du _Brocken_ ou _Blocksberg_. La matiere dominante est
alors le _granit_; mais il est tout en blocs le long de cette route, et
ces blocs se trouvent a une telle distance de tout sommite intacte de
cette pierre, qui est aise de juger non seulement qu'ils ne sont pas
dans leur place originaire, mais encore qu'il ne sont arrives la par
aucune des causes naturelles qui agissent dans les montagnes; savoir,
la pesanteur, la pente, et le cours des eaux. Ce sont donc de violentes
explosions qui ont disperse ces blocs; et alors ils deviennent un
nouveau trait cosmologique de quelque importance: car rien ne se meut,
ni ne paroit s'etre mu depuis bien des siecles, dans ces lieux qui
montrent tant de desordre: un tapis de verdure couvre tout, en
conservant les contours baroques du sol. Le betail ne sauroit paturer
dans de telles prairies; mais l'industrieux montagnard fait y
faucher[29].
[Note 29: M. de Saussure endeavours to explain those appearances of
transported blocks of granite by another cause; this is a certain
_debacle_ of the waters of the earth, which I do not understand. M. de
Luc again attempts to explain it by violent explosions; I suppose he
means those of a volcano. But he has not given us the evidence upon
which such an opinion may be founded, farther than by saying that those
blocks could not have come there by the natural operations of the
surface. By this must be meant, that, from the nearest summit of
granite, there is not, at present, any natural means by which these
blocks might be transported to that place. But it is not with the
present state of things that we are concerned, in explaining the
operations of a distant period. If the natural operations of the surface
change the shape of things, as is clearly proved by every natural
appearance, Why form an argument against a former transaction, upon the
circumstances of the present state of things? Our author does not
seem to perceive, that, from this mode of reasoning, there is is an
insuperable objection to his violent explosions having been employed in
producing those effects. For, had there been such a cause, the evidence
of this must have remained; if the surface of the earth does not undergo
great changes: If, again, this surface be in time much changed, How can
we judge from the present shape, what might have been the former posture
of things?
This author, indeed, does not allow much time for the natural operations
of the globe to change its surface; but, if things be not greatly
removed from the state in which the violent operations of the globe had
placed them, Why does he not point out to us the source of this great
disorder which he there perceives? From what explosion will be explained
the blocks of granite which are found upon the Jura, and which must have
come from the mass of _Mont Blanc_? If these dispersed blocks of
stone are to be explained by explosion, there must: have been similar
explosions in other countries where there is not the smallest appearance
of volcanic eruptions; for, around all our granite mountains, and I
believe all others, there are found many blocks of granite, traveled at
a great distance, and in all directions.]
"_Oberbruck_, ou nous avions ete la precedente fois, se trouva sur notre
route, et nous y passames aussi la nuit, dans l'esperance de pouvoir
monter le lendemain sur le _Brocken_; mais il fut encore enveloppe de
nuages; ainsi nous continuames a marcher vers _Clausthal_, passant de
nouveau par le _Bruchberg_, ou le _sable_ et ses gres recouvrent le
_schiste_; puis arrivant a une autre sommite, nous y trouvames la meme
pierre _sableuse_ par couches, melee de parcelles de _schiste_, que nous
avions vue sur les montagnes _calcaires d'Elbingerode_. Il est donc
toujours plus certain que le sol primordial de toutes ces montagnes
existoit sous les eaux de l'ancienne mer; puisqu'il est recouvert de
diverses fortes de depots, connus pour appartenir a la _mer_; et que les
_fentes_ des _filons_ existoient dans cette _mer ancienne_; puisqu'elle
en a rempli elle-meme quelques unes, et qu'elle a recouvert de ses
depots quelques autres _filons_ tout formes. Quant a celles des matieres
de ces _filons_, qui ne paroissent pas etre _marines_ (et c'est de
beaucoup la plus grande quantite), j'ai toujours plus de penchant d'en
attribuer une partie a l'operation des _feux souterreins_, a mesure que
je vois diminuer la probabilite de les assigner entierement a _l'eau_.
Mais quoi-qu'il en soit, ces gangues ne font pas de meme date que les
montagnes[30].
[Note 30: I most willingly admit the justness of our author's view, if
he thus perceives the operation of fire in the solids of our earth; but
it is not for the reasons he has given us for discovering it here more
than in other places; for there is not a mineral vein, (so far at least
as I have seen), in which the appearances may be explained by any thing
else besides the operation of fire or fusion. It is not easy to conceive
in what manner our author had conceived the opinions which he has
displayed in these letters. He had no opinion of this kind, or rather he
was persuaded that subterraneous fire had no hand in the formation of
this earth before he came to this place of the Hartz; here he finds
certain appearances, by which he is confirmed in his former opinion,
that water had operated in forming mineral veins; and then he forms the
idea that subterraneous fire may have operated also. But, before the
discovery of the chasms in the schistus mountains having been filled
with the stratified materials of the sea, How had he supposed veins to
be filled? If this philosopher had before no opinion of subterraneous
fire, as instrumental in that operation, How comes he now to change that
former opinion? For, unless it be the extraordinary manner of filling
these open crevices in the mountains by matter deposited immediately
from the sea, there is certainly no other appearance in this mineral
country of the Hartz, that may not be found in any other, only perhaps
upon a smaller scale.]
"Le lendemain de notre arrivee a _Clausthal_, qui etoit le 13e, nous
allames visiter d'autres mines de _fer_ en montagnes secondaires,
situees au cote oppose du Hartz. Elles sont aupres de _Grund_ l'une
des _villes de mines_, et pres du lieu ou sortira la nouvelle _galerie
d'ecoulement_ a laquelle on travaille, etc.
"Arrives a _Grund_ les officiers mineurs vinrent, comme a l'ordinaire,
accompagner Mons. de _Reden_ aux _mines_ de leur departement. Celles-ci,
sans etre plus extraordinaires que celles qui nous avions vues a
_Elbingerod_, ou sans aider mieux jusqu'ici a expliquer ce qu'elles ont
toutes d'extraordinaire, nous donnent au moins des indices probables
de grands accidens. Ces montagnes de _Grund_ sont encore de l'espece
remarquable, dont la base est de _schiste_, et le haut de _pierre a
chaux_. Les mines qu'on y exploit sont de _fer_, et se trouvent dans
cette matiere _calcaire_; mais elles y sont sous des apparences
tout-a-fait etranges. La montagne ou nous les vimes principalement le
nomme _Iberg_. On y poursuit des masses de _pierre a fer_, de l'ensemble
desquelles les mineurs ne peuvent encore se rendre compte d'une maniere
claire. Ils ont trouve dans cette montagne des _ca__vernes_, qui
ressemblent a l'encaissement de _sillons_ deja exploites, ou non formes;
c'est-a-dire, que ce sont des _fentes_ presque verticales, et vides, Le
_minerai_ qu'ils poursuivent est en _Rognons_; c'est a dire, en grandes
masses sans continuite decidee. Cependant ces masses semblent se
succeder dans la montagne suivant une certaine direction; tellement que
les mineurs savent deja les chercher, par des indices d'habitude.
La substance de cette _pierre a fer_ particuliere renferme des
crystallizations de diverses especes. Il y a des _druses de quartz_, ou
de petits cristaux de quartz qui tapissent des cavites; il y a aussi du
_spath_ commun, et de celui qu'on nomme pesant; on y trouve enfin une
forte de crystallization nommee _Eisenman_ (_homme de fer_) par les
mineurs; se sont des amas de cristaux noir-atres, qui ressemblent a
des groupes de grandes lentilles plattes, et ces cristaux sont
_ferrugineux_.
"Entre les signes de bouleversement que renferme ce lieu, est un
rocher nomme _Gebichensten_, qui est en _pierre a chaux_, ce que
_l'Ebrenbreitstein_ de _Coblentz_ est en pierre sableuse: c'est-a-dire,
que ses _couches_, remplies de _corps marins_, sont presque verticales;
ceux de ces corps qu'on y trouve en plus grande quantite, sont des
_madrepores_. Ce rocher s'eleve comme un grand obelisque, au-dessus des
_cavernes_, dont j'ai parle; montrant par le cote ses _couches_, qui se
trouvent, comme je l'ai dit, dans une situation presque verticale. Sa
base est deja bien minee, tant par les _cavernes_, que par la _pierre
a fer_ qu'on en tire; et je ne me hasardai dessus, que parce que je me
dis, qu'il y a des millions contre un a parier, que ce n'est pas le
moment ou il s'enfoncerait. Mais je n'en dirois pas autant, s'il
s'agissoit de m'y loger a demeure.
"Quoique tout ce lieu la soit fort remarquable, il se pourrait que ce
ne fut qu'un phenomene particulier. Les _cavernes_ peuvent devoir leur
origine a la meme cause que celle de Schartzfeld; et le derangement des
rochers superieurs a des enfoncemens occasionnes par ces _cavernes_.
Rien n'est si difficile que de retracer aujourd'hui ces fortes
d'accidens a cause des changemens que le tems y a operes. S'ils sont
arrives sous les eaux de la _mer_, on concoit aisement les alterations
qui ont du succeder; et si c'est depuis que nos continens sont a sec,
les eaux encore, tant interieures qu'exterieures, et la vegetation, en
ont beaucoup change l'aspect."
This author has a theory by which he explains to himself the former
residence of the sea, above the summits of our mountains; this,
however, is not the theory by which we are now endeavouring to explain
appearances; we must therefore be allowed to reason from our own
principles, in considering the facts here set forth by our author.
Nothing, I think, is more evident, than that in this mineral country of
the Hartz, we may find the clearest marks of fracture, elevation, and
dislocation of the strata, and of the introduction of foreign matter
among those separated bodies. All those appearances, our author would
have to be nothing but some particular accident, which is not to enter
into the physiology of the earth. I wish again to generalise these
facts, by finding them universal in relation to the globe, and
necessarily to be found in all the consolidated parts of our land.
It was not to refute our author's reasoning that I have here introduced
so much of his observations, but to give an extensive view of the
mineral structure of this interesting country. This therefore being
done, we now proceed to what is more peculiarly our business in this
place, or the immediate subject of investigation, viz. the distinction
of primary and secondary strata.
"Dans le voisinage de cette montagne, il y a une autre fort
interessante, que je vis le jour suivant. Quoiqu'en traitant des
volcans, j'aie demontre que la formation des montagnes, par soulevement,
etoit sans exemple dans les faits, et sans fondement dans la theorie, je
ne laisseroi pas de m'arreter au phenomene que presente cette montagne;
parce qu'il prouvera directement que les _couches calcaires_ au moins,
ont ete formees _a la hauteur ou elles sont_; c'est-a-dire qu'elles
n'ont pas ete soulevees.
"Voulant prendre l'occasion de mon retour a _Hanovre_, pour traverser
les avant-corps du _Hartz_, dans quelque nouvelle direction; je resolus
de faire ce voyage a cheval, et de prendre ma route droite vers
_Hanovre_, au-travers des collines; ce qui me conduisit encore a _Grund_
puis a _Muenchehof Brunshausen, Engelade, Winsenburg_ et _Alfeld_, ou
enfin, traversant la _Leine_ j'entrai dans la grande route.
"Je quittai donc _Clausthal_ (et avec bien du regret) le 14 au matin;
et revenant d'abord a _Grund_, je le laissai sur ma droite, ainsi
que _l'Iberg_; et plus loin, du meme cote, une autre montagne nommee
_Winterberg_ dont la base est _schiste_, et le sommet plus haut que
Clausthal, entierement compose de _couches calcaires_. De _Grund_ je
montai vers une montagne nommee _Ost Kamp_; et je commencai la a donner
une attention particuliere au sol. Le long de mon chemin, je ne trouvai
longtemps que des schistes, qui montroient leurs points en haut, comme a
l'ordinaire, et avec tous leurs tortillemens de feuillets. Mais arrive
au haut de la montagne, j'y vis des carrieres de _pierre a chaux_, ou
les couches absolument regulieres, et qui ont peu d'epaisseur sur le
_schiste_ suivent parfaitement les contours du _sommet_. Ces lits de
_pierre a chaux_ n'ont certainement pas ete souleves du fond de la _mer_
sur le dos des schistes; lors meme qu'a cause de la grande inclinaison
des feuillets de ceux-ci on voudroit le attribuer a quelque revolution
telle que le _soulevement_; (ce que je n'admettrois point). Car si ces
lits _calcaires_, ayant ete faits au fond de la _mer_, avoyent ete
souleves avec les schistes, ne feroient-ils pas brises et bouleverses
comme eux? Il est donc evident, que quoiqu'il soi arrive au schiste qui
les porte, ces lits, et tous les autres de meme genre qui sont au haut
de ces montagnes, ont ete deposees au niveau ou ils sont; et que
par consequent la _mer_ les surpassoit alors. Ainsi le systeme de
soulevement perd son but, s'il tend a expliquer pourquoi nous avons des
_couches_, formees par la mer, qui se trouvent maintenant si fort au
dessus de son niveau. Il est evident que ces _couches_ n'ont pas ete
soulevees; mais que la _mer_ s'est _abaissee_. Or c'est la le grand
point cosmologique a expliquer: tous les autres, qui tiennent a la
structure de certaines montagnes inintelligibles, n'appartiendront qu'a
_l'histoire naturelle_, tant qu'ils ne se lieront pas avec celui-la."
Here are two things to be considered; the interesting facts described
by our author, and the inference that he would have us draw from those
facts. It would appear from the facts, that the body of schistus below,
and that of lime-stone above, had not undergone the same disordering
operations, or by no means in the same degree. But our author has formed
another conclusion; he says, that these lime-stone strata must have been
formed precisely in the place and order in which they lie at present;
and the reason for this is, because these strata appeared to him to
follow perfectly the contour of the summit of this mountain. Now, had
there been in the top of this mountain a deep hollow encompassed about
with the schistus rock; and had this cavity been now found filled with
horizontal strata, there might have been some shadow of reason for
supposing those strata to have been deposited upon the top of the
mountain. But to suppose, _first_, that shells and corals should be
deposited upon the convex summit of a mountain which was then covered by
the sea; _secondly_, that these moveable materials should remain upon
the summit, while the sea had changed its place; and, _lastly_, that
those shells and corals left by the sea upon the top of a mountain
should become strata of solid limestone, and have also metallic veins
in it, certainly holds of no principle of natural philosophy that I am
acquainted with. If, therefore, such an appearance as this were to be
employed either in illustration or confirmation of a theory, it
would itself require to be explained; but this is a task that this
cosmologists does not seem willing to undertake.
He has formed a hypothesis for explaining the general appearance of that
which was once the bottom of the sea being now found forming the summits
of our mountains; but surely this philosopher will acknowledge, that
those natural appearances, in any particular place, will be the same,
whether we suppose the bottom of the sea to have been raised, as in the
present theory, or the surface of the sea to have sunk according to his
hypothesis. For, it is equally easy to suppose a portion of the earth
to have been raised all this height, as to suppose all the rest of the
surface of the globe to have sunk an equal space, while a small portion
of the bottom of the sea, remaining here and there fixed in its place,
became the highest portion of the globe. Consequently, whatever evidence
this philosopher shall find in support of his theory of the present
earth, (a subject which it is not our purpose to examine) it cannot be
allowed that he has here brought any argument capable of disproving the
elevation of the bottom of the sea; a supposition which other theories
may require.
I would now observe, in relation to the present theory, that so far
as this author has reasoned justly from natural appearances, his
conclusions will be found to confirm the present supposition, that there
is to be perceived the distinction of primordial, and that of secondary,
in the masses of this earth, without altering the general theory either
with respect to the original formation of those masses, or to their
posterior production.
Here one of two things must be allowed; either that those strata
of schistus had been broken and distorted under a mass of other
superincumbent strata; or that those superincumbent strata had been
deposited upon the broken and distorted strata at the bottom of the sea.
Our author, who has examined the subject, inclines to think, that this
last has been the case. If, therefore, strata had been deposited upon
broken and bare rocks of schistus, it is probable that these had been
sunk in the sea after having been exposed to the atmosphere, and served
the purpose of land upon the globe.[31]
[Note 31: This is also supported by another very interesting observation
contained in this letter. M. de Luc observes, that in this country the
schistus is generally covered by strata of lime-stone, and that these
lime-stone strata are again covered with those of sand-stone, in which
are found a great many fragments of schistus lying flat. Therefore,
while those sand-stone strata were collecting at the bottom of the sea,
there had been rocks of schistus in some other place, from whence those
fragments bad been detached.]
An example of the same kind also occurs in the _Discours sur l'Histoire
Naturelle de la Suisse_; and this author of the _Tableaux de la Suisse_
has given a very distinct description of that appearance, which is
perhaps the more to be valued as a piece of natural history, as this
intelligent author does not pretend to any geological theory, but simply
narrates what he has seen, with such pertinent observations on
the subject as naturally must occur to a thinking person on the
spot.--(Discours, etc. page 228. Entree au pays de Grisons).
"Du village d'Elen on continue a monter le reste du petit vallon pendant
une lieue et demie parmi les memes especes de pierres qu'on vient de
decrire; en passant au travers de bois et de forets de sapins et de
quelques paturages dont ce haut est couvert, on parvient au pied du
Bundnerberg, montagne des grisons, qui forme la tete du vallon. On
laisse a droite un fond ou espece d'entonnoir, entoure de tres-hautes
montagnes inaccessibles, pour s'enfourrer a gauche entre des rochers qui
font fort resserres, ou coule un torrent. Ce lieu seroit horreur si
on ne se trouvoit accoutume, par degres, a voir de ces positions
effrayantes: tout y est aride, il n'y a plus d'arbres ni de vegetaux ce
sont des rochers entasses les un sur les autres; ce lieu paroit d'autant
plus affreux que le passage a ete subit, et qu'en sortant de bois et des
forets, on se trouve tout-a-coup parmi ces rochers qui s'elevent comme
des murailles, et dont on ne voit pas la cime; cette gorge ou cette
entree qui se nomme Jetz, est la communication du Canton du Glaris aux
Gritons; on a dit precedemment qu'il y en avoit une plus aisee par
le Gros-Thal ou le grand vallon. Ce passage est tres-curieux pour la
Lithogeognosie, il est rare de trouver autant de phenomenes interessans
rassembles, et des substances aussi variees par rapport a leurs
positions; c'est le local qui merite le plus d'etre examine en Suisse,
et la plus difficile que nous ayons parcouru. On se souviendra que nous
avons continuellement monte depuis Glaris, et que nous nous trouvons au
pied de ces montagnes ou de ces pics etonnans qui dominent les hautes
Alpes; on trouve ici la facilite peu commune de pouvoir examiner, et
voir le pied ou les fondemens de ces colosses qui couronnent le globe,
parce qu'ils sont ordinairement entoures de leurs debris et de leurs
eboulemens qui en cachent le pied. Ici c'est une roche de schiste
bleuatre, dure et compact, traversee de filons de quartz blanc, et
quelquefois jaunatre, dans laquelle on a taille un sentier pour pouvoir
en franchir le pied. Cette roche s'eleve a une hauteur prodigieuse,
est presque verticale, et ces couches sont a quatre-vingt degres
d'inclinaison. L'imagination est effrayee de voir que de pareilles
masses ayent pu etre ebranlees et deplacees au point d'avoir fait
presque un quart de conversion. Apres avoir monte et suivi cette roche
parmi les pierres et les decombres, une heure et demie, on trouve
cette roche de schiste surmontee d'autres rochers fort hauts qui sont
calcaires, et dont les lits sont fort horizontaux. Les schistes,
qui sont directement sous les roches calcaires, conservent la meme
inclinaison qu'elles ont a leur pied."
Here is an observation which certainly agrees with that given by M. de
Luc, and would seem to confirm this conclusion, that strata had been
deposited upon those _schisti_ after they had been changed from their
natural or horizontal position, and become vertical; at the same time,
this conclusion is not of necessary consequence, without examining
concomitant appearances, and finding particular marks by which this
operation might be traced; for the simply finding horizontal strata,
placed above vertical or much inclined schiste, is not sufficient, of
itself, to constitute that fact, while it is acknowledged that every
species of fracture, dislocation, and contortion, is to be found among
the displaced strata of the globe.
Since writing this chapter, I am enabled to speak more decisively upon
that point, having acquired more light upon the subject, as will appear
in the next chapter.
CHAP. VI.
The Theory of interchanging Sea and Land illustrated by an
Investigation of the Primary and Secondary Strata.
SECT. I.--A distinct View of the Primary and Secondary Strata.
Having given a view of what seems to be the primary and secondary
strata, from the observations of authors, and having given what was
my opinion when I first wrote that chapter, I am now to treat of this
subject from observations of my own, which I made since forming that
opinion.
From Portpatrick, on the west coast, to St Abb's Head, on the east,
there is a tract of schistus mountains, in which the strata are
generally much inclined, or approaching to the vertical situation; and
it is in these inclined strata that geologists allege that there is not
to be found any vestige of organised body. This opinion, however, I have
now proved to be erroneous.
There cannot be any doubt with regard to the original formation of those
stratified bodies, as having been formed of the materials that are
natural to this earth, viz. the detritus of former bodies; and as having
been deposited in water, like the horizontal strata: For the substances
and bodies of which they are visibly composed are no other than those
which form the most regular horizontal strata, and which are continually
traveling, or transported at the bottom of the sea, such as gravel, and
sand, argillaceous and micaceous bodies.
On each side of this ridge of mountains, which towards the east end is
but narrow, there is a lower country composed of strata in general more
horizontal; and among which strata, besides coal, there are also found
the relics of organised bodies.
Abstracting at present from any consideration of organised bodies among
the materials of those strata, it may be affirmed, that the materials
which form the strata in the mountains and in the low country, are
similar, or of the same nature; that they have, in both places, been
consolidated by the same means, viz. heat and fusion; and that the same
or similar accidents have happened to them, such as change from their
original position, and mineral veins traversing them in various shapes.
Yet still there is a distinctive character for those two bodies, the
alpine and the horizontal strata; for, while the horizontal position
appears natural to the one, and the changes from that particular state
to be only an accident, the vertical position appears to be more natural
to the other, which is seldom found horizontal.
Therefore, altho' it is unquestionable that the strata in the alpine and
low countries had the same or a similar original, yet, as the vertical
position, which is the greatest possible change in that respect, is more
natural to the alpine strata, or only necessary in the natural order of
those bodies, we are to consider this great disorder or change from the
natural state of their original formation, as the proper character of
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