Illogical Geology Part 6

Or Zittel's confession that:

"The terminology which has been introduced in the innumerable monographs of special fossil faunas in the majority of cases makes only the slenderest pretext of any connection with recent systematic zoology; if there is a difficulty, then stratigraphical arguments are made the basis of a solution. Zoological students are as a rule too actively engaged and keenly interested in building up new observations to attempt to spell through the arbitrary palaeontological conclusions arrived at by many stratigraphers, or to revise their labors from a zoological point of view."

Hence I have no reluctance in saying that, in the present confused state of the science, it is utterly impossible to find out the truth as to how many hundreds of these "genera" of the Paleozoic rocks may have survived to the present, though having skipped perhaps all the formations of the intervening millions of years. I doubt not that the number is enormously large, though as I have not attempted "to spell through the arbitrary palaeontological conclusions" scattered through the literature, I can only depend on a few though striking examples that lie on the open pages of the ordinary text-books.

The larger mammals can of course furnish us no examples, for the "age"

in which they abounded is quite conveniently modern, and is separated from the present by no great lapse of time. Of the smaller marsupials, quite a number of jaw-bones have been found in the Jura.s.sic and Tria.s.sic, one from the latter being strikingly like the living _Myrmecobius_ of Australia. They are scarcely more numerous in the Cretaceous of America, while in the foreign rocks of this system Dana says that "Only one species had been reported up to 1894." Those strange, sad-eyed creatures called Lemurs deserve a pa.s.sing notice, for though now confined as to their typical forms to the island of Madagascar, their fossils seem as exclusively confined to the temperate regions of the New and the Old World. Flower and Lydekker enumerate about fifteen fossil species, and add that:

"... it is very noteworthy that all these types seem to have disappeared from both regions with the close of the upper portion of the Eocene period."[45]

But this jump from the "Eocene period" to the present is as nothing compared with the secular acrobatics of some of the fishes and especially of the invertebrates. The living Cestraciont sharks, of which there are four species found in the seas between j.a.pan and Australia, seem to disappear with the Cretaceous, skipping the whole Tertiary Epoch, as do also a tribe of modern barnacles which, as Darwin says, "coat the rocks all over the world in infinite numbers." The Dipnoans or Lung-fishes (having lungs as well as gills, such as the _Ceratodus_ and _Lepidosiren_), which are represented by several living species in Australia and South Africa, are the remains of a tribe found in whole shoals in the Carboniferous, Tria.s.sic and Jura.s.sic rocks, but not, so far as I know, in any of the intervening rocks. The living Ceratodus was only discovered in 1870, and was regarded as a marvel of "persistence."

On a pinch, as when his native streams dry up, this curious fellow can get along all right without water, breathing air by his lungs like a land animal. If in the meantime he was off on a trip to the moon, he must have "persisted" a few million years without either.

But his cousin, the _Polypterus_ of the Upper Nile, has a still more amazing record, for he has actually skipped all the formations from the Devonian down to the modern; while the Limuloids or sea scorpions have jumped from the Carboniferous down.

The Mollusks and Brachiopods would afford us examples too numerous to mention. How is it possible that these numerous families disappear suddenly and completely with the Mesozoic or even the "early"

Palaeozoic, and are not found in any "later" deposits, though alive now in our modern world? Parts of Europe and America have, we are told, been down under the sea and up again a dozen times since then; why then should we not expect to find abundant remains of these "persistent"

types in the Mesozoic and Tertiaries? Surely these feats of time-acrobatics show the folly of arranging contemporaneous, taxonomic groups in single file and giving to each a time value.

The Chalk points a similar lesson. It was not till the time of the "Challenger" Expedition that the modern deposits of Globigerina ooze, made up of species identical with those of the Chalk, were known to be now forming over vast areas of the ocean floor. In the words of Huxley, these modern species "bridge over the interval between the present and the Mesozoic periods."[46]

As for the silicious sponges found in the Chalk, which were such puzzles for the scientists during the first half of the nineteenth century, because their living forms were unknown, the deep-sea investigations have solved the problem, for in 1877 Sollas demonstrated "the ident.i.ty of their structure with that of living Hexactinellids, Lithistids, and Monactinellids."[47]

And yet with all the alleged vicissitudes of the continents during the millions of years since the Cretaceous age, there is so far as I am aware not a trace of either the chalk or the sponges in any of the "subsequent" rocks. Pieces of Cretaceous rock are of course found thus sporadically as boulders, but there is no natural deposit of this kind.

But in the light of these modern discoveries why is not the Chalk of "the white dear cliffs of Dover," full of modern living species as we now know it to be, just as "recent" a deposit as the "late" Tertiaries or the Pleistocene?

Another good ill.u.s.tration of the absurdity of the present arrangement of the rocks is found in the Echinoderms--crinoids, star-fishes, sea-urchins, etc. Of the latter Prof. A. Aga.s.siz found in the deep waters of the West Indies, four genera of Echinids or sea-urchins of the "later Tertiary," =but 24 genera of the "early" Tertiary, 10 of the Cretaceous, and 5 of the Jura.s.sic=.[48]

But far from being uncommon we know that similar discoveries have been in almost constant progress during the last half century. And were it not that "zoological students are," as Zittel says, "too actively engaged and keenly interested in building up new observations to attempt to spell through the arbitrary palaeontological conclusions" found in the "dead weight of stratigraphical-palaeontological literature," there is no telling what hosts of similar facts might not be pointed to regarding the forms found in all the "older" rocks.

Of the star-fishes and serpent-stars (_Asteridea_ and _Ophiuridea_), Zittel says: "It would seem that the Palaeozoic 'sea-stars' differed very little from those in the seas of the present age." (p. 395.) The crinoids, we are told, "are among the earliest in geological history,"

making up vast limestones of the Palaeozoic rocks; and forms scarcely separable from the modern are found in the Jura.s.sic, but so far as the text-books tell us are =absolutely unknown in any later deposits=. But there are several modern genera, such as Pentacrinus, Rhizocrinus, Bathycrinus, etc., found in the deep waters of nearly all the oceans.

The genus Rhizocrinus was discovered off the coast of Norway about the sixties of the last century. But what were these creatures doing since "Jura.s.sic times," while the "pulsating crust" was putting parts of the continents under the sea for ages at a stretch? Why did they form no deposits during the Cretaceous, Eocene, Miocene or Pliocene ages? Surely the absurdity of the present arrangement is evident to a child. During all these intervening ages the climate of the globe continued of the same remarkable mildness, fossils of all these formations being found about as far north as explorers have ever gone. Why did the crinoids and polyp-corals suspend business from "Jura.s.sic times" to the "recent,"

merely to accommodate a modern theory? Dana says that "The coral reefs of the Oolyte in England consist of corals of the same group with the reef-making species of the existing tropics,"[49] and he argues from this fact that the mean temperature of the waters must have been about 69 deg. F. But a luxuriant vegetation still continued in the Arctic regions during the Cretaceous and the Tertiaries. How absurd to say that these corals built no reefs about the European coasts during all these ages. Or, to put the matter in another way, considering how many of their characteristic types are alive in our modern seas, why should we say that the crinoidal or coral limestones of the Mesozoic or Palaeozoic rocks are not as recent as the nummulitic limestones of the Eocene or any late Tertiary deposits?

It is no answer at all to tell us that, though the general types are the same, the =species= of the Palaeozoic and the Mesozoic are entirely extinct. I have not had the courage "to attempt to spell through" all the "dead weight" of the modern literature, but I think that the world would like more satisfactory proof of this oft-repeated a.s.sertion than the customs and traditions of a hundred years, and the exigencies of a fanciful theory. This worn-out argument of Cuvier's about extinct species has kept up a running fight with common sense for many decades, and though driven backward from one point to another over the long thin line of this taxonomic series of the fossil world, it still contests every inch of ground.

But let us try the tree-ferns and cycads of the coal beds of the "older"

rocks. In northern regions they are not found "later" than the Tria.s.sic and Jura.s.sic, and doubtless the same holds good of the rocks in the Tropics, where the modern species now live in fair abundance. But how did they come to s.h.i.+ft to the Tropics so many millions of years before the palms, etc., of the Tertiaries thought it time to do the same? The climate had not changed a bit: how did they come to scent the coming "Glacial Age" so much earlier than their more highly organized fellows?

The "Challenger" expedition found some Cyathophylloid corals now building reefs at the bottom of our modern ocean. The geologists had already a.s.signed =the last= of them to the Carboniferous and Permian rocks with the idea that they were extinct. But where have these fellows kept themselves during all the intervening ages while the continents were deep under the ocean time and time again? or why are not the rocks containing their fossils as "recent" as any deposits on the globe?

And so I might go on. There is hardly a tribe found in the "older" rocks which does not have its living representatives of to-day, and with, I believe, a fair proportion of the species identical; though in hundreds, perhaps thousands, of cases these species, genera, or even whole tribes, have somehow skipped all the intervening formations.

But let us drop this method of studying our subject, and look at it from a slightly different standpoint.

Thus Dana[50] says that:

"The absence of Lamellibranchs in the Middle Cambrian, although present in both Lower and Upper, means =the absence of fossils from the rocks, not of species from the faunas=."

He puts this in italics by way of emphasis, for it is certainly a reasonable idea, and as A. R. Wallace says, "no one =now= doubts that where any type appears in two remote periods it must have been in existence during the whole intervening period, although we may have no record of it."[51] But what would be the result if we only extend this idea to its logical conclusion? It seems to be an effort to avoid one of the absurdities of the onion-coat theory, without, however, discarding that theory altogether.

In speaking of some corals and crinoids of the Devonian which "were absent" from some of the divisions of this formation because the conditions of the seas about New York "were unfavorable," Dana says that "they were back when the seas were again of sufficient purity."[52]

In his review of these formations he enlarges on this subject:

"At the close of the early Devonian the evidences of clear seas--the corals and crinoids, with most of the attendant life--disappear, migrating no one knows whither.... With the variations in the fineness, or other characteristics of the beds as H. S. Williams has ill.u.s.trated, the species vary.... =The faunas of each stratum are not strictly faunas of epochs or periods of time, but local topographical faunas.= After the Corniferous period, corals, crinoids, and trilobites still flourished =somewhere=, as before, but they are absent from the Central Interior until the Carboniferous age[53] opens."

Here we are certainly getting a refres.h.i.+ng breath of common-sense geology; but what would become of current theories if we enlarge a little on this idea?

What if the gigantic dinosaurs of the Cretaceous or the equally marvellous mammals of the "early" Tertiaries of the Western States, described by Marsh and Cope, and the Pleistocene mammals of other parts of America and of Europe and Northern Siberia, "are not strictly faunas of epochs or periods of time, but local topographical faunas?" What if the world-wide limestones of the Cambrian and Silurian, and the no less enormous or widespread nummulitic limestones of the Eocene, extending from the Alps to Eastern Asia, and const.i.tuting mountains ten, fifteen, or twenty thousand feet high--what if these are possibly =contemporaneous with one another=? Supposing the coal-measures of Nova Scotia and Pennsylvania, and the Cretaceous and Tertiary lignites of Vancouver Island, Alberta, and the Western States are not strictly floras of epochs or periods of time, but local topographical floras?[54]

But it must be confessed that the logical extension of this broad view of the fossils, and the projection of our modern zoological provinces and zones back into the fossil world would mean the death-blow to the life succession theory, and might have a very disturbing effect upon certain theories about human origins and other genetic relations.h.i.+ps which have grown quite popular since the middle of the last century.

FOOTNOTES:

[40] "History," pp. 327, 341.

[41] See LeConte, "Evol. and Religious Thought," p. 253.

[42] "Modern Ideas of Evol.," p. 35.

[43] See "Manual," pp. 487-8.

[44] "Manual," p. 776.

[45] "Mammals, etc." p. 696.

[46] "Discourses Biol. and Geol.," p. 347.

[47] Zittel, "Hist. of Geo.," p. 388.

[46] Dana, "Manual," p. 59.

[49] "Manual," p. 793.

[50] "Manual," p. 488.

[51] "Distribution of Life," p. 33.

[52] "Manual," p. 611.

[53] "Manual," pp. 628-9.

[54] Note--This is only carrying the argument a little further than Huxley does when he says that "A Devonian fauna and flora in the British Islands may have been contemporaneous with Silurian life in North America, and with a Carboniferous fauna and flora in Africa.

Geographical provinces and zones may have been as distinctly marked in the Palaeozoic epoch as at present." "Discourses," p. 286.