in a sea gradually shallowing, and out of which the land had already partially emerged.

A continuous ocean spreads over the space now occupied by the British islands in the tract covered by the green fields and brown moors of our own country, the bottom, for a hundred yards downwards, is composed of the debris of rolled pebbles and coarse sand intermingled, long since consolidated into the lower member of the Old Red Sandstone; the upper surface is composed of banks of sand, mud, and clay; and the sea, swarming with animal life, flows over all. My present object is to describe the inhabitants of that sea.

Of these, the greater part yet discovered have been named by Agassiz, the highest authority as an ichthyologist in Europe or the world, and in whom the scarcely more celebrated Cuvier recognized a naturalist in every respect worthy to succeed him. The comparative amount of the labors of these two great men in fossil ichthyology, and the amazing acceleration which has taken place within the last few years in the progress of geological science, are illustrated together, and that very strikingly, by the following interesting fact a fact derived directly from Agassiz himself, and which must be new to the great bulk of my readers. When Cuvier closed his researches in this department, he had named and described, for the guidance of the geologist, ninety-two distinct species of fossil fish; nor was it then known that the entire geological scale, from the Upper Tertiary to the Grauwacke inclusive, contained more. Agassiz commenced his labors; and, in a period of time little exceeding fourteen years, he has raised the number of species from ninety-two to sixteen hundred. And this number, great as it is, is receiving accessions almost every day. In his late visit to Scotland, he found leven new species, and one new genus, in the collection of

Lady Cumming of Altyre, all from the upper beds of that lower member of the Old Red Sandstone represented by the dark-colored schists and inferior sandstones of Caithness. He found forty-two new species more in a single collection in Ireland, furnished by the Mountain Limestone of Armagh.

Some of my humbler readers may possibly be repelled by his names; they are, like all names in science, unfamiliar in their respect to mere English readers, just because they are names not for England alone, but for England and the world. I am assured, however, that they are all composed of very good Greek, and picturesquely descriptive of some peculiarity in the fossils they designate. One of his ichthyolites, with a thorn or spine in each fin, bears the name of Acanthodes, or thorn-like; another with a similar mechanism of spines attached to the upper part of the body, and in which the pectoral or hand-fins are involved, has been designated the Cheiracanthus, or thorn-hand; a third covered with curiously-fretted scales, has been named the Glyptolepis, or carved-scale; and a fourth, roughened over with berry-like tubercles, that rise from strong osseous plates, is known as the Coccosteus, or berry-on-bone. And such has been his principle of nomenclature. The name is a condensed description. But though all his names mean something, they cannot mean a great deal; and as learned words repel unlearned readers, I shall just take the liberty of reminding mine of the humbler class, that there is no legitimate connection between Geology and the dead languages. The existences of the Old Red Sandstone had lived for ages, and had been dead for myriads of ages, ere there was Greek enough in the world to furnish them with names. There is no working-man, if he be a per

son of intelligence and information, however unlearned, in the vulgar acceptation of the phrase, who may not derive as much pleasure and enlargement of idea from the study of Geology, and acquaint himself as minutely with its truths, as if possessed of all the learning of Bentley.

CHAPTER III.

Lamarck's Theory of Progression illustrated. Class of Facts which give Color to it. - The Credulity of Unbelief.-M. Maillet and his Fish-birds. - Gradation not Progress. - Geological Argument. The Present incomplete without the Past. — Intermediate Links of Creation. Organisms of the Lower Old Red Sandstone. The Pterichthys. — Its first Discovery. — Mr. Murchison's Decision regarding it. Confirmed by that of Agassiz. - Description. The several Varieties of the Fossil yet discovered. - Evidence of Violent Death in the Attitudes in which they are found. The Coccosteus of the Lower Old Red. - Description. — Gradations from Crustacea to Fishes. Habits of the Coccosteus. any Conception too extravagant for Nature to realize.

Scarcely

MR. LYELL's brilliant and popular work, The Principles of Geology, must have introduced to the knowledge of most of my readers the strange theories of Lamarck. The ingenious foreigner, on the strength of a few striking facts, which prove that, to a certain extent, the instincts of species may be improved and heightened, and their forms changed from a lower to a higher degree of adaptation to their circumstances, has concluded that there is a natural progress from the inferior orders of being towards the superior; and that the offspring of creatures low in the scale in the present time, may hold a much higher place in it, and belong to different and nobler species, a few thousand years hence. The descendants of the ourang-outang, for instance, may be employed in some future age in writing treatises on Geology, in which they shall have to describe the remains of the quadrumana as belonging to an extinct order. Lamarck himself, when bearing home in triumph with him the skeleton of some huge.

salamander or crocodile of the Lias, might indulge, consistently with his theory, in the pleasing belief that he had possessed himself of the bones of his grandfather-a grandfather removed, of course, to a remote degree of consanguinity, by the intervention of a few hundred thousand great-greats. Never yet was there a fancy so wild and extravagant but there have been men bold enough to dignify it with the name of philosophy, and ingenious enough to find reasons for the propriety of the name.

The setting-dog is taught to set; he squats down and points at the game; but the habit is an acquired one- -a mere trick of education. What, however, is merely acquired habit in the progenitor, is found to pass into instinct in the descendant: the puppy of the setting-dog squats down and sets untaught the educational trick of the parent is mysteriously transmuted into an original principle in the offspring. The adaptation which takes place in the forms and constitution of plants and animals, when placed in circumstances different from their ordinary ones, is equally striking. The woody plant of a warmer climate, when transplanted into a colder, frequently exchanges its ligneous stem for a herbaceous one, as if in anticipation of the killing frosts of winter; and, dying to the ground at the close of autumn, shoots up again in spring. The dog, transported from a temperate into a frigid region, exchanges his covering of hair for a covering of wool; when brought back again to his former habitat, the wool is displaced by the original hair. And hence, and from similar instances, the derivation of an argument, good so far as it goes, for changes in adaptation to altered circumstances of the organization of plants and animals, and for the improvability of instinct. But it is easy driving a principle too far. The elasticity of a common bow, and the