United States or French Guiana ? Vote for the TOP Country of the Week !
Driven out of their native chalk, rolled for ages on a sea-beach, they have tried to get a few centuries' sleep in the Eocene sands on the top of the chalk hills behind us, while the London clay was being deposited peacefully in the tropic sea below; and behold, they are swept out, once more, and hurled pell-mell upon the clay, two hundred feet over our heads. Over our heads, remember.
Here is a beautiful mass of green, and not far away the trail that leads from the plateau to the river is in sight. El Tovar Point. Its elevation is seven thousand feet. Coconino Forest and Angel Plateau. To the west and south is the Coconino Forest; beyond is seen the dry bed of the ancient Eocene lake, and the blue ridge, where the lava-flows from Mount Floyd shut in the view.
That it was an extinct mammal of the whale tribe has since been placed beyond all doubt by discovery of the entire skull of another fossil species of the same family, having the double occipital condyles only met with in mammals, and the convoluted tympanic bones which are characteristic of cetaceans. Lapse of Time between Cretaceous and Eocene Periods. Maestricht Beds.
Pshaw!" he finished up witheringly, "you fellers ain't got shut o' last century." "Maybe we haven't," Tresler retorted, with a good-humored laugh; "but your enterprise has carried you so far ahead of time that you've overlapped. I tell you, man, you're back in the savage times. You're groping in the prehistoric periods Jurassic, Eocene, or some such."
And the knowledge we now possess justifies us completely in the anticipation, that when the still lower Eocene deposits, and those which belong to the cretaceous epoch, have yielded up their remains of ancestral equine animals, we shall find, first, a form with four complete toes and a rudiment of the innermost or first digit in front, with probably a rudiment of the fifth digit in the hind foot; while, in still older forms, the series of the digits will be more and more complete, until we come to the five-toed animals, in which, if the doctrine of evolution is well founded, the whole series must have taken its orgin.
They overlie the uppermost of an extensive series of Eocene deposits of marine, brackish, and fresh-water formations, which rest on the Chalk and terminate upward in strata corresponding in age to the Paris gypsum, and containing the same extinct genera of quadrupeds, Palaeotherium, Anoplotherium, and others which Cuvier first described. Corbula pisum. Cyrena semistriata. Cerithium elegans.
Their early Eocene ancestors, the Creodonts, gave rise in the Eocene to forms which we may regard as the forerunners of the cat-family and dog-family, to which most of our familiar Carnivores belong. Cyonodon has a wolf-like appearance, and Amphicyon rather suggests the fox. Primitive weasels, civets, and hyaenas appear also in the Eocene.
But the most important discovery of all is the Orohippus, which comes from the Eocene formation, and is the oldest member of the equine series as yet known. Here we find four complete toes on the front limb, three toes on the hind-limb, a well-developed ulna, a well-developed fibula, and short-crowned grinders of simple pattern.
Some of these are remarkable enough; but they all sink into insignificance beside the mammalian remains which the lower eocene deposits of the Paris basin present to us, shewing that the land had now become the theatre of an extensive creation of the highest class of animals. Cuvier ascertained about fifty species of these, all of them long since extinct.
CAMELS AND LLAMAS. The line of camels and llamas developed in North America, where the successive changes from an early Eocene ancestor, no larger than a rabbit, are traced step by step to the present forms, as clearly as is the evolution of the horse.
Word Of The Day