With the coming in of the Triassic epoch began the great deposits of Red Sandstone, Muschel-Kalk, and Keuper, in Central Europe. They united the Belgian island to the region of the Vosges and the Black Forest, while they also filled to a great extent the channel between Belgium and the Bohemian island. Thus the land slowly gained upon the Triassic ocean, shutting it within ever-narrowing limits, and preparing the large inland seas so characteristic of the later Secondary times. The character of the organic world still retained a general resemblance to that of the Carboniferous epoch. Among Radiates, the Corals were more nearly allied to those of the earlier ages than to those of modern times, and Crinoids abounded still, though some of the higher Echinoderm types were already introduced. Among Mollusks, the lower Bivalves, that is, the Brachiopods and Bryozoa, still prevailed, while Ammonites continued to be very numerous, differing from the earlier ones chiefly in the ever-increasing complications of their inner partitions, which become so deeply involuted and cut upon their margins, before the type disappears, as to make an intricate tracery of very various patterns on the surface of these shells. The most conspicuous type of Articulates continues as before to be that of Crustacea; but Trilobites have finished their career, and the Lobster-like Crustacea make their appearance for the first time. It does not seem that the class of Insects has greatly increased since the Carboniferous epoch; and Worms are still as difficult to trace as ever, being chiefly known by the cases in which they sheltered themselves. Among Vertebrates, the Fishes still resemble those of the Carboniferous epoch, belonging principally to the Selachians and Ganoids. They have, however, approached somewhat toward a modern pattern, the lobes of the tail being more evenly cut, and their general outline more like that of common fishes. The gigantic marsh Reptiles have become far more numerous and various. They continue through several epochs, but may be said to reach their culminating point in the Jurassic and Cretaceous deposits.