Protozoa. + CHAPTER VIII. THE MESOZOIC AGES. Physically, the transition from the Permian to the Trias is easy. In the domain of life a great gulf lies between; and the geologist whose mind is filled with the forms of the Palæozoic period, on rising into the next succeeding beds, feels himself a sort of Rip Van Winkle, who has slept a hundred years and awakes in a new world. The geography of our continents seems indeed to have changed little from the time of the Permian to that next succeeding group which all geologists recognise as the beginning of the Mesozoic or Middle Age of the world's history, the Triassic period. Where best developed, as in Germany, it gives us the usual threefold series, conglomerates and sandstones below, a shelly limestone in the middle, and sandstones and marls above. Curiously enough, the Germans, recognising this tripartite character here more distinctly then in their other formations, named this the _Trias_ or triple group, a name which it still retains, though as we have seen it is by no means the earliest of the triple groups of strata. In England, where the middle limestone is absent, it is a "New Red Sandstone," and the same name may be appropriately extended to Eastern America, where bright red sandstones are a characteristic feature. In the Trias, as in the Permian, the continents of the northern hemisphere presented large land areas, and there were lagoons and landlocked seas in which gypsum, magnesian limestones, and rock salt were thrown down, a very eminent example of which is afforded by the great salt deposits of Cheshire. There were also tremendous outbursts of igneous activity along the margins of the continents, more especially in Eastern America. But with all this there was a rich land flora and a wonderful exuberance of new animal life on the land; and in places there were even swamps in which pure and valuable beds of coal, comparable with those of the old coal formation, were deposited. The triple division of the Trias as a cycle of the earth's history, and its local imperfection, are well seen in the European development of the group, thus:-- German Series. French Series. English Series. Keuper, Sandstone and } Marnes Irisées {Saliferous and gypseous Shale } { Shales and Sandstones. Muschelkalk, Limestone} Calcaire Coquillier {Wanting. and Dolomite } Bunter, Sandstone and } Grès bigarré {Sandstone and Conglomerate } { Conglomerate.