Such was the dawn or introduction to the present order of things. In the language of geology it is called the EOCENE AGE of the world, because it approaches in its organic productions to those which are now existing, and containing a very few recent species, not more than three or four per cent. Nature did not all at once leap from one epoch to another. In the tertiary deposits there is evidence of successive creations, rests and pauses, as it were, before the final and crowning consummation of her works. More and more analogies begin to manifest themselves in the ascending series of the group. The Miocene, or middle period, develops a yet larger proportion, though not a majority, of the present inhabitants of the sea. The Pleiocene arrangements follow; and in the shells and terrestrial products of this group the modern characters and types are still more clearly discernible. When we reach the highest members, the difficulties of separation from the modern deposits begin to multiply; the mineral qualities and mere earthy beds are not distinguishable; while, on the other hand, in all the animal forms and huge colossal proportions of Mastodons and Theriums, there are the unequivocal markings of an extinct anterior age. CHAPTER VII. THE MAMMOTH PERIOD. The tertiary deposits are referable to three great divisions, containing subdivisions, some of marine, some of fresh water origin, and severally characterized by their fossil remains. The terms Eocene, Miocene, and Pleiocene, are applied to them in their respective order of superposition, as the lower, middle, and upper groups. The London basin belongs to the first of these divisions. When these congeries of beds were completed, and the bottom of the sea was elevated, a fresh water occupation of the district appears to have prevailed. And during the supremacy of this reign of the Naïads it was, that England was tenanted by herds of large quadrupeds, tigers, hyenas, and the companions of the untamable class, whose haunts are now in the Indian jungle, or the forests and prairies of America.