Page:Popular Science Monthly Volume 10.djvu/221

Rh through to the present day. Such is the case with the Globigerinæ, the skeletons of which, aggregated together, form the great mass of our chalk in England. That Globigerina can be traced down to the Globigerinæ which live at the surface of our great oceans, and the remains of which, falling to the bottom of the sea, give rise to a chalky material. So that it must be admitted that certain species of creatures living at the present day show no sign of modification or transformation in the course of a lapse of time as great as that which carries us back to the period of chalk. There are groups of species so closely allied together that it needs the eye of a naturalist to distinguish them one from another. If we pay attention to these, we find that a vastly greater period must be allotted, in some cases, to these persistent forms. In the chalk itself, for example, there is the fish belonging to the highest and the most differentiated of osseous fishes, which go by the name of Beryx. That fish is one of the most beautiful of fossils found in our English chalk. It can be studied anatomically, so far as the hard parts are concerned, almost as well as if it were a recent fish. We find that that fish is represented at the present day by very closely-allied species which are living in the Pacific and Atlantic Oceans. But we may go still farther back, and we find, as I mentioned to you yesterday, that the Carboniferous formations in Europe and in America contain the remains of scorpions in an admirable state of preservation, and those scorpions are hardly distinguishable from such as now live. I do not mean to say that they are not distinguishable, but they require close scrutiny to distinguish them from the scorpions which exist at the present day.

More than that. At the very bottom of the Silurian series, in what is by some authorities termed the Cambrian formation, where all signs of life appear to be dying out—even there, among the few and scanty animal remains which exist, we find species of molluscous animals which are so closely allied to existing forms that at one time they were grouped under the same generic name. I refer to the well known Lingula of the Lingula flags, lately, in consequence of some slight differences, placed in the new genus Lingulella. Practically it belongs to the same great generic group as the Lingula, which you will find at the present day upon the shores of Australia. And the same thing is exemplified if we turn to certain great periods of the earth's history—as, for example, throughout the whole of the Mesozoic period. There are groups of reptiles which begin shortly after the commencement of this period, as the Ichthyosauria and the Plesiosauria, and they abound in vast numbers. They disappear with the chalk, and throughout the whole of that great series of rocks they present no important modifications. Facts of this kind are undoubtedly fatal to any form of the doctrine of evolution, which necessitates the supposition that there is an intrinsic necessity on the part of animal forms which once come into existence to undergo