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It presents three complete toes one large median and two smaller lateral ones; and there is a rudiment of that digit, which answers to the little finger of the human hand. The European record of the pedigree of the horse stops here; in the American Tertiaries, on the contrary, the series of ancestral equine forms is continued into the Eocene formations.
The succession of forms which he has brought together carries us from the top to the bottom of the Tertiaries. Firstly, there is the true horse. Then comes the Protohippus, which represents the European Hipparion, having one large digit and two small ones on each foot, and the general characters of the fore-arm and leg to which I have referred.
The other great types of the Animal Kingdom are very fully represented in the Tertiaries, and in their general appearance they approach much more closely those of the present creation than of any previous epochs.
But even a superficial study of these fossils shows us that the animals and plants which live at the present time have had only a temporary duration; for the remains of such modern forms of life are met with, for the most part, only in the uppermost or latest tertiaries, and their number rapidly diminishes in the lower deposits of that epoch.
There are families of fishes whose type of construction has persisted all the way from the carboniferous rock right up to the cretaceous; and others which have lasted through almost the whole range of the secondary rocks, and from the lias to the older tertiaries.
The Pyrenees, too, and Alps, have both undergone elevation since the deposition of the tertiaries; and in Sicily there are mountains which have risen three thousand feet since the deposition of some of the most recent of these rocks.
The colors of the spectrum undergo some very curious changes under artificial light, especially from a gas consuming as much carbon as our common carburetted hydrogen. The greens, owing to the absorption of the yellow rays, become the brighter, and the orange and red tones, from the same reason, the more intense, while the paler violets and, in fact, all the tertiaries, of a bluish cast lose "
An Australian fauna would be found underlying an American fauna, and the transition from the one to the other would be as abrupt as that between the Chalk and lower Tertiaries; and as the drainage-area of the newly formed extension of the American continent gave rise to rivers and lakes, the mammals mired in their mud would differ from those of like deposits on the Australian side, just as the Eocene mammals differ from those of the Purbecks.
There are no great gulfs between epochs and formations no successive periods marked by the appearance of plants, of water animals, and of land animals, 'en masse'. Every year adds to the list of links between what the older geologists supposed to be widely separated epochs: witness the crags linking the drift with older tertiaries; the Maestricht beds linking the tertiaries with the chalk; the St.
There are families of fishes whose type of construction has persisted all the way from the carboniferous rock right up to the cretaceous; and others which have lasted through almost the whole range of the secondary rocks, and from the lias to the older tertiaries.
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