Vietnam or Thailand ? Vote for the TOP Country of the Week !
Updated: May 27, 2025
Beds of Passage between the Lias and Trias, Rhaetic Beds. Triassic Mammifer. Triple Division of the Trias. Keuper, or Upper Trias of England. Reptiles of the Upper Trias. Foot-prints in the Bunter formation in England. Dolomitic Conglomerate of Bristol. Origin of Red Sandstone and Rock-salt. Precipitation of Salt from inland Lakes and Lagoons. Trias of Germany. Keuper. St.
They abandoned the defensive system of warfare and boldly took up the offensive. No doubt, like their descendants, the belemnites were exceedingly active and voracious creatures. FISHES AND AMPHIBIANS. In the Triassic and Jurassic, little progress was made among the fishes, and the ganoid was still the leading type.
Perhaps now and then the basins became long, brackish estuaries, whose low shores were swept by the incoming tide and were in turn left bare at its retreat to receive the rain prints of passing showers and the tracks of the troops of reptiles which inhabited these valleys. The Triassic rocks are mainly red sandstones, often feldspathic, or arkose, with some conglomerates and shales.
This accounts for the very scanty traces to be found in America of the secondary deposits; for the Permian, Triassic, and Jurassic beds, instead of being raised to form successive shores, along which their deposits could be accumulated in regular sequence, as had been the case with the Azoic, Silurian, and Devonian deposits in the northern part of the United States, were constantly sinking, so that the Triassic settled above the Permian, the Jurassic above the Triassic, and so on, each set of strata thus covering over and concealing the preceding one.
It is the triassic formation, or the commencement of the mesozoic epoch, which has received this smallest inheritance from preceding ages. The other formations not uncommonly exhibit 60, 80, or even 94 per cent. of genera in common with those whose remains are imbedded in their predecessor.
These sea monsters disported along the Pacific shore over northern California in Triassic times, and the bones of immense members of the family occur in the Jurassic strata of Wyoming. Like whales and seals, the ichthyosaurs were descended from land vertebrates which had become adapted to a marine habitat. PLESIOSAURS were another order which ranged throughout the Mesozoic.
As far as the bird is concerned, this may be doubted on the ground that it first appears in the upper or later Jurassic, and is even then still largely reptilian in character. We must remember, however, that the elevation of the land and the cold climate lasted until the second part of the Triassic, and it is generally agreed that the bird may have been evolved in the Triassic.
Our English salt supply is chiefly derived from the Cheshire and Worcestershire salt-regions, which are of triassic age. Many of the places at which the salt is mined have names ending in wich, such as Northwich, Middlewich, Nantwich, Droitwich, Netherwich, and Shirleywich.
How do the Triassic sandstones and shales compare in hardness with the igneous and metamorphic rocks about them? The Jurassic strata are wanting over the Triassic areas and over all of eastern North America. Was this region land or sea, an area of erosion or sedimentation, during the Jurassic period?
In fact, as I have recently endeavoured to prove to the Society, there was an Arctogaeal continent and an Arctogaeal province of distribution in Triassic times as there is now; and the Sauropsida and Marsupialia which constituted that fauna were, I doubt not, the progenitors of the Sauropsida and Marsupialia of the whole Mesozoic epoch.
Word Of The Day
Others Looking