Part 6 (2/2)

3. According to the present chronological arrangement of the rocks, very many genera, often whole tribes of animals, are found as fossils only in the oldest rocks, and _have skipped all the others_, though found in comparative abundance in our modern world. Very many others have skipped from the Mesozoic down, while still others skip large _parts_ of the series of successive ages.

These absurdities would all be avoided by acknowledging that the current distinctions as to the ages of the fossils are purely artificial, and that one fossil is intrinsically just as old or as young as another.

4. It is now known that any kind of ”young” beds whatsoever, Mesozoic, Tertiary, or even Pleistocene, may be found in such _perfect conformability_ on some of the very oldest beds over wide stretches of country that ”the vast interval of time intervening is unrepresented either by deposition or erosion”; while in some instances these age-separated formations so closely resemble one another in structure and in mineralogical make-up that, ”were it not for fossil evidence, one would naturally suppose that a single formation was being dealt with”

(McConnell); and these conditions are ”not merely local, but persistent over wide areas” (A. Geikie), so that the ”numerous examples” (Suess) of these conditions ”may well be cause for astonishment” (Suess).

A still more astonis.h.i.+ng thing from the standpoint of the current theories is that these conformable relations of incongruous strata are often _repeated over and over again in the same vertical section_, the same kind of bed reappearing alternately with others of an entirely different ”age,” that is, appearing ”as if _regularly interbedded”_ (A.

Geikie) with them, in a manifestly undisturbed series of strata.

Here again we have a very formidable series of facts whose gravamen is directed wholly against the artificial distinctions in age between the different groups of fossils; and their argument is an eloquent plea that the fossils are neither older nor younger but all of a similar age.

5. Our last fact demands a somewhat more extended consideration; but it may be stated in advance briefly as follows:

In very numerous cases and over hundreds and even thousands of square miles, the conformable conditions specified in the previous fact are exactly reproduced _upside down_; that is, very ”old” rocks occur with just as much appearance of natural conformability on top of very ”young”

rocks, the area in some instances covering many hundreds of square miles, and in one particular instance in Montana and Alberta covering about five or six thousand square miles of area.

The first notable example of this phenomenon was discovered at Glarus, Switzerland, a good many years ago; since which time this locality has become a cla.s.sic in geological literature, and has called out many ponderous monographs in German and French by such men as Heim, Schardt, Lugeon, Rothpletz, and Bertrand. This example, which was first (1870) called the Glarner Double Fold by Escher and Heim, is now universally called a nearly flat-lying ”thrust fault,” in accordance with the explanations since adopted of similar phenomena elsewhere. Without obtruding unnecessary technicalities upon my non-professional readers, I may quote the words of Albert Heim as to the conditions as now recognized in these parts:

”These flat-lying faults, of which those at Glarus were the first to be discovered, _are a universal_ _phenomenon_ in the Northern and Central Alps.”[41]

[Footnote 41: ”Der Bau der Schweizeralpen,” p. 17.]

The favorite method of explaining these conditions has slightly changed within recent years, as already remarked. For whereas the cla.s.sic example at Glarus was at first spoken of as a double fold-in from both sides toward the Sernf Valley, this is now universally spoken of as a ”thrust fault,” with the rocks all pushed one way. Incidentally it may be noted that this very fact that what was long regarded as two completely overturned folds is now spoken of as one flat-lying thrust fault, is _prima facie_ evidence that there is here _no physical proof_ of any real overturning of the strata, such as we do find on a very small scale in true folded rocks. The latter can usually be measured in yards, feet, or inches; while in this example at Glarus the area involved would be measured in many miles, and in some very similar examples to be presently mentioned from America the measurement could best be made in degrees of lat.i.tude and longitude or in arcs of the earth's circ.u.mference. In these larger examples it is manifestly impossible that there should be any physical evidence sufficient to indicate a huge earth movement of this character, especially when, as is usually the case, both the upper and the lower strata are _quite uninjured in appearance_. No; the fossils are here in the wrong order, that is all. And so, to save the long established doctrines of a very definite order of successive life-forms, this theory of a ”thrust fault”

is offered as the best available explanation. As Dr. Albert Heim himself once expressed it very naively in a letter to the present writer, that the strata over these large areas are in a position manifestly at direct disagreement with the received order of the fossils, ”is a fact which can be clearly seen,--only we know not yet how to explain it in a mechanical way.”

An example in the Highlands of Scotland was about the next to be discovered. Here, as Dana says, ”a ma.s.s of the oldest crystalline rocks, many miles in length from north to south, was thrust at least ten miles westward over younger rocks, part of the latter fossiliferous;” and he further declares, ”the thrust planes _look like planes of bedding, and were long so considered._”[42]

Sir Archibald Geikie and others had at first described these beds as naturally conformable; and when at length they were convinced that the fossils would not permit this explanation, Geikie gives us some very picturesque details as to how natural they look.

The thrust planes, he says, are with much difficulty distinguished ”from ordinary stratification planes, like which they have been plicated, faulted, and denuded. Here and there, as a result of denudation, a portion of one of them appears capping a hilltop. One almost refuses to believe that the little outlier on the summit does not lie normally on the rocks below it, but on a nearly horizontal fault by which it has been moved into its place.”

Of a similar example in Ross s.h.i.+re he declares:

”Had these sections been planned for the purpose of deception, they could not have been more skilfully devised, ... and no one coming first to the ground would suspect that what appears to be a normal stratigraphical sequence is not really so.”[43]

[Footnote 42: ”Manual,” pp. 111, 534.]

[Footnote 43: _Nature_, November 13, 1884, pp. 29-35.]

Here again we have unequivocal testimony from the most competent of observers that there is _no physical evidence whatever_ to lead any one to say that a ponderous scale of the earth's crust was really pushed up on top of other portions, as this makes.h.i.+ft theory of ”thrust faults”

involves. The _fossils are here in the wrong order_, just as in the case at Glarus; that is all. The facts seem to be a flat contradiction to the theory of definite successive ages, and to save the theory this explanation of a ”thrust fault” is invented, though there is absolutely no physical evidence of any disturbance of the strata.

Our next stopping place is in the Southern Appalachian Mountains of eastern Tennessee and northern Georgia. Here we have the Carboniferous strata dipping gently to the southeast, like an ordinary low monocline, _under_ Cambrian or Lower Silurian, one of these so-called faults having a reported length of 375 miles,[44] while in another instance the upper strata are said to have been pushed about eleven miles in the direction of the ”thrust.”[45] These conditions, we are told, ”have provoked the wonder of the most experienced geologists,”[46] because of the perfectly natural appearance of the surfaces of the strata affected; or as this same writer puts it, ”The mechanical effort is great beyond comprehension, but the effect upon the rocks is inappreciable,” and ”the fault dip is often parallel to the bedding of the one or the other series of strata.”[47] Which means, in other words, that these ”thrust planes” _look just like ordinary planes of bedding between conformable strata_.

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