tiary epoch advances, the boreal races retreat farther to the north, some of the old pliocene families again return and spread over European latitudes, and other and newer forms, in the course of creation, begin to appear.

It is now the current era of geological history, whose vital record is the silts and marls of filled-up lakes, the alluvium of rivers and estuaries, the growth of peat-bogs and morasses, the stalagmite of fissures and caverns, and the tufa and ashes of volcanoes. In these superficial accumulations, which meet us at every turn, and are still in course of formation, every imbedded organism is fresh and familiar. With the exception of a few extinctions, the species yet flourish in the same latitudes, and the lists of the palæontologist become identical with those of the botanist and zoologist. The peat-bogs of Europe are replete with the mosses, grasses, willows, hazels, birches, firs, and oaks that still spread over our swamps, and adorn our forests. The tundras of Siberia, the jungle-soil of India, and the cypress-swamps of America, are in like manner composed of the plants now peculiar to these regions; and though in the course of geological change, local features may have varied, the main aspects of the Current Flora continue, zone for zone, and province for province, with little alteration or disturbance.

When we turn to the Fauna, the case is much the same. The most ancient lake-marls of Europe are thronged with lymnea, paludina, cyclas, planorbis, scarcely, if at all, distinguishable from those that now people our fresh-water ponds; and the marine shells of our estuarine silts and raised beaches-the mussels, cockles, oysters, periwinkles, whelks, silver-shells, and clams-with a few local variations, are identical with those that inhabit the surrounding seas. When we turn to the terrestrial fauna, the change, chiefly

through the instrumentality of men, becomes a little more decided and apparent. The mammoth and mastodon, the Irish deer and urus, the cave-bear and hyæna, that seem to have roamed over Europe during the dawn of the post

Megaceros Hibernicus, or Gigantic Irish Deer.

tertiary period, become extinct, though their congeners still flourish in Asia and Africa. As we ascend to later deposits, species, or, it may be, merely varieties of horse, ass, ox, deer, goat, sheep, bear, wild boar, wolf, and fox become the more frequent forms; and ultimately, in the more recent accumulations, the bones, whether of mammals, birds, reptiles, or fishes, become indistinguishable, even in variety, from those that are now our associates in the scheme of vitality.

And it is just in this palpable approach to existing nature that we begin to detect the earliest traces of the human species. First, and far back among the river-silts and peat-bogs and cave-earths, we discover his rude stone-implements and weapons, his tree-canoes, and the embers of the fires which he alone of all animals can either kindle or sustain. Side by side with these remains, occasionally lie

bones of the mammoth, rhinoceros, and Irish deer; but whether these may not have been washed up, drifted, and re-assorted from earlier deposits, is a question not always easily determinable. However the question may be ultimately answered, one thing is certain, that just as the mammoths and mastodons drop away, and the horse, ox, goat, and sheep begin to spread over Europe in increasing numbers, so the traces of primeval man become more frequent and unmistakable. In all likelihood-nay, it is all but certain that over the plains and through the forests of the Old World man hunted the Irish deer and speared the mammoth, just as at a later period, and in the same region, he lassoed the wild horse and impounded the urus and buffalo. With regard to this subject, however—viz., the first appearof man-much unnecessary discussion has taken place, and a great deal of uneasy tenderness been displayed. Like other events in geological history, we have at present no means of assigning to it a definite date in years and centuries. The time is merely relative, and all that science can safely do is to ascribe it to an early, though not to the very earliest, stages of the pleistocene epoch. Whether this was six thousand or sixteen thousand years ago, we cannot by any known data determine, though this much is evident, that the amount of change since effected on the physical and vital world, as well as the course of civilisation itself, would, at the current rate of progress, require for their elimination a much more extended period than is usually allowed.

And here it may be remarked, that while in these superficial accumulations we find frequent traces of primeval man-his stone-implements, tree-canoes, &c. -we rarely or ever discover the remains of man himself. Not a human bone has been detected, even in the valley of the Somme, where the flint-implements lie in thousands

-not a fragment where other fragments more slender and fragile occur in abundance. It is true, the search has yet been confined to a small portion of Europe; but the fact is somewhat significant, and forbids any attempt at generalisation till wider areas in Asia and America have been explored. Till this is done, and till bones and crania have been found and examined, it will be impossible to decide the ethnographic character of these early men, or to say whether they appeared in Asiatic, European, and American species, and consequently arose from various creative centres, or were merely time-distributed varieties of a single and one-created form. Geology, as far as the facts have been collated, gives no countenance to the idea of a plurality of creative centres. On the contrary, the sameness of the stone-implements, wherever they have been found, evince

1, 2, From valley of Somme; 3, 4, 5, England; 6, 7, 8, Canada; 9, 10, Scandinavia.

a similarity of idea-the same conception and the same design. Those, therefore, who, disregarding the unity of

language, mental constitution, and religious sentiment of the human race, will still contend for several creative centres, must seek other corroboration of their hypothesis than is yet afforded by the discoveries and indications of geology.

As the pre-glacial passed gradually into the glacial, and the glacial into the post-glacial period; so the pre-human passes insensibly into the pre-historic, and the pre-historic into the historical ages. And even when the historical arrives, the record of our own race is often less certain in the hands of the historian than in those of the geologist. Geology by no means ceases where history begins. Vast physical changes have occurred since man first peopled the globe. Some regions have been rising above the waters of the ocean, others have been sinking. Rivers have changed their courses; lakes and estuaries have been converted into alluvial tracts; and volcanoes have given birth to new mountain masses.

"There rolls the deep where grew the tree;
Oh, Earth, what changes hast thou seen!
There, where the long street roars, has been
The stillness of the central sea."

Of such mutations, history is altogether silent; and even where she speaks, her utterance is frequently of less value than her silence. The earth, however, pens and preserves with fidelity her own record: geology becomes her interpreter. As in the physical world, so also in the vital, important mutations have been effected, even within historical times. Many local removals of species and several general

* For an able and lucid exposition of the recent changes to which the earth has been subjected, the reader is referred to Sir Charles Lyell's Principles of Geology--a work which should be carefully studied by every one who would lay a logical and solid foundation for his geological knowledge.