Geological facts; or, the crust of the earth, what it is, and what are its uses

by W. G. Barrett

Moses.

In our rapid sketch of the materials constituting the crust of the earth, we first of all, in that imaginary section which we supposed to have been laid bare to us, studied the characters of the hypogene rocks,[^[110]] that make up the Azoic period, in which, with the exception of a few zoophytes, all nature was void of animal, life and possessed only by the genius of dread silence. Rising higher, we surveyed the Palæozoic or primary rocks, where the fishes of the Old Red Sandstone convinced us of progress in the forms of life, and taught us our first lesson in the ascending scale of those types of life with which Palæontology has now made us familiar. Leaving this period at the Carboniferous era, we entered upon the Mesozoic,[^[111]] or Secondary period, ushered in amidst strange convulsions that must again and again have rendered the earth “without form and void;” and here we found ourselves in company with the strange and gigantic remains of a higher order of vertebrated animals, the saurians, the crocodile-kings of a bygone period; and as we pondered these hieroglyphics of past generations, our souls “were seized the prisoners of amaze;” and now, in our upward ascent, leaving behind us the scenes

“Where eldest Night

And Chaos, ancestors of nature, held

Eternal anarchy,”

we come to the Cainozoic,[^[112]] or Tertiary Rocks, where other and higher types of life are found. Huge mammals, beasts of prodigious size, are now found inhabitants of the earth, the precursors of man—reasoning, intelligent, responsible man, who is presently to make his appearance on this great theatre of life, “made a little lower than the angels,” to have dominion over the works of Jehovah’s power.

Sir H. de la Beche proposes, for tertiary, the term “supercretaceous;” it is, however, of little consequence which term is adopted, the meaning in each case being the same, that all the rocks or strata lying above the chalk are to be considered as belonging to the tertiary system or series. Confessedly, it is a dark period in the history of those successive creations which have been engaging our attention, for we can trace no near connexion between the secondary or older, and tertiary or newer formations. That is to say—and the bare statement appears so sufficient and final a refutation of what has been termed the “development hypothesis,” now recognised as contradictory to fact and to Scripture—that there are not known to exist in any of these newer strata the same beings, or the descendants of the same beings, that were found upon the earth at the termination of the chalk deposit.

Nor is this all; not only are none of the old fossils found in any one of the three divisions of this system, but we are introduced at once to so many new ones, that their species and genera are almost endless; and he is not only a geologist of mark, but a most singularly accomplished geologist, who thoroughly understands their minute subdivisions, and can appropriately classify the fossils of this most fossiliferous era. To make the matter as simple as possible, let us add that “the broad distinction between tertiary and secondary rocks is a palæontological one. None of the secondary rocks contain any fossil animals or plants of the same species as any of those living at the present day. Every one of the tertiary groups do contain some fossil animals or plants of the same species as those now living.”[^[113]]

Having alluded to the threefold division of this series of rocks, we shall proceed to notice them, dwelling a while upon each, and showing the principle on which each is based, as originated and enunciated by Lyell. Of the three divisions, the first is called Eocene (ēōs, the dawn, and kainŏs, recent), by which term is represented the oldest or lowest of this tripartite series. Then we have the Miocene (meiōn, less, and kainŏs, recent)—a name, we think, not the most appropriate, and likely to mislead the beginner, because really it represents a series of beds, more and not less recent than the Eocene; but the idea of the name is this (and it must be carefully borne in mind), that although it is more recent than the series of beds below, it is less recent than those above; it is nearer the “dawn” of our present era than the Eocene, but not so near the dawn as the Pliocene. This last term, the Pliocene (from pleiōn, more, and kainŏs, recent), is applied to the newest of the beds of the tertiary series in which there are found many more recent than extinct shells. The Tertiary system or series, then, is divided into these three sections: viz. 1. The older Tertiary or Eocene; 2. The middle Tertiary or Miocene; and 3. The newer Tertiary or Pliocene.

We used a term just now, in quoting from Mr. Juke’s most useful manual, which we will explain; we said, the “distinction between the secondary and tertiary rocks is wholly a palæontological one;” that is, it is a distinction founded not on the character of the rocks, but on the character of the organic remains found in the rocks. “This character,” says Sir Charles Lyell, “must be used as a criterion of the age of a formation, or of the contemporaneous origin of two deposits in different places, under very much the same restrictions as the test of mineral composition.