United States or North Korea ? Vote for the TOP Country of the Week !
Post-glacial : Upper diluvial. Glacial : Lower diluvial. Arverne : Upper pliocene. Subapennine : Lower pliocene. Falun : Upper miocene. Limbourg : Lower miocene. Aquitaine : Upper oligocene. Ligurium : Lower oligocene. Gypsum : Upper eocene. Coarse chalk : Middle eocene. London clay : Lower eocene. White chalk. : Upper cretaceous. Green Sand : Middle cretaceous. Neocomian : Lower cretaceous.
But although all the observed phenomena bearing on the post-glacial history of this colossal tree point to the conclusion that it never was more widely distributed on the Sierra since the close of the glacial epoch; that its present forests are scarcely past prime, if, indeed, they have reached prime; that the post-glacial day of the species is probably not half done; yet, when from a wider outlook the vast antiquity of the genus is considered, and its ancient richness in species and individuals; comparing our Sierra Giant and Sequoia sempervirens of the Coast Range, the only other living species of Sequoia, with the twelve fossil species already discovered and described by Heer and Lesquereux, some of which seem to have flourished over vast areas in the Arctic regions and in Europe and our own territories, during tertiary and cretaceous times, then indeed it becomes plain that our two surviving species, restricted to narrow belts within the limits of California, are mere remnants of the genus, both as to species and individuals, and that they probably are verging to extinction.
Some peculiar Australian types are represented on the summit of Kini Balu in Borneo. None of these species, of course, are found in the intervening lowlands, and the only possible explanation of their identity is the conception of a common post-glacial origin, coupled with complete stability.
As regards the geological indications of age, the best authority seems to point to the first appearance of man in the post-glacial times: that is to say, that the gravels in which the palaeolithic implements are found were deposited by the action of fresh water after the great glacial period, when, at any rate, Northern Europe, a great part of Russia, all Scandinavia, and part of North America were covered with icefields, the great glaciers of which left their mark in the numerous scoopings out of ravines and lake beds and in the raising of banks and mounds, the deposit of boulders, and the striation of rocks in situ, which so many districts exhibit.
And because here the snow-fountains lay at a greater height, while the rock, an exceedingly hard quartzite, offered superior resistance to post-glacial agents, the ice-characters are on a larger scale, and are more sharply defined than any we have noticed elsewhere, and it is probably here that the last lingering glacier of the basin was located.
My feet rest on the topmost step of a stone stairway worn hip-deep in the rocks of eternity by the moccasined tread of foot-prints that run back, not to A. D. or B. C., but to those post-glacial æons when the advances and recessions of an ice invasion from the Poles left seas where now are deserts; when giant sequoia forests were swept under the sands by the flood waters, and the mammoth and the dinosaur and the brontosaur wallowed where now nestle farm hamlets.
Turning to the Kangaroo especially, it continued, "If you can bring yourself to speak to anything so obtrusive and gossiping, without any ancestry or manners whatever, you will be able to learn all you need from that bird. Humans and Wagtails fraternise together. They're both post-glacial." "I knew you could advise me," said the Kangaroo gratefully. "Oh!
The monuments of the Ice Age in the Great Basin have been greatly obscured and broken, many of the more ancient of them having perished altogether, leaving scarce a mark, however faint, of their existence a condition of things due not alone to the long-continued action of post-glacial agents, but also in great part to the perishable character of the rocks of which they were made.
If this be so, the whole derangement, although Pleistocene, may have been anterior to the human epoch, or rather to the earliest date to which the existence of man has as yet been traced back. Post-glacial Strata containing Remains of Mastodon giganteus in North America. Scarcity of Marine Shells in Glacial Drift of Canada and the United States.
Now these historic ditches and root-bowls occur in all the present sequoia groves and forests, but, as far as I have observed, not the faintest vestige of one presents itself outside of them. We therefore conclude that the area covered by sequoia has not been diminished during the last eight or ten thousand years, and probably not at all in post-glacial time.
Word Of The Day