or less overlaid with the deposits of the Keuper series. The Thecodontosaurus and Paloeosaurus described by Dr. Riley and Mr. Stutchbury occur in a magnesian conglomerate of Keuper age, which was long considered to be the equivalent of part of the strata now called Permian. My explanation of their stratigraphical position is, that these Dinosaurian reptiles lived upon land moderately elevated all through the Permian and Bunter epochs, and that subsequently their remains were buried in the shingly beds of the Keuper inland sea, which formed the last of a long series of inland continental waters that prevailed over a large part of the territory now called Europe, from the close of the Silurian period onward to the Rhaetic beds. First, there are the great lake-formed strata of the Old Red Sandstone ; secondly, the Carboniferous formations, to a great extent terrestrial ; thirdly, the Permian series ; and, fourthly, the Triassic and partly the Rhaetic beds ; after which, during Liassic times, by subsidence, the sea invaded the land, and a mere group of islands occupied the site of much of what is now Europe. Further, I think it may be proved that the great continental areas of North America and Europe, and even of Asia and Africa, were already sketched out during the long geological period I have indicated, and that the great similarity in lithological character between the Permian and Triassic areas of Europe, America, and India is owing not to any cause producing depositions of red strata from all the waters of the world at these periods, but simply to special conditions of inland continental waters at various epochs of time.
This leads to the important question of the possible continuity of the same types of terrestrial as distinguished from marine life during the whole of this long period. Writers on geological subjects have often been apt to treat of the fossil records of the earth's history as being chiefly marine. If, however, the reasoning used in the foregoing pages is good, then we have a series of records indicating continental land surfaces containing great fresh and salt lakes, extending over a very large portion of all known geological time ; and this, as far as time is concerned, possesses a significance quite as great as that of the marine formations, even though some of these inland-formed strata are almost destitute of the remains of life. Geographical continuity of continental land during a period that embraces several great geological epochs implies probable continuity of continental genera, if not of species. The Labyrinthodontia common to all the formations from the Upper Trias to the Coal-measure Anthracosaurus bear upon this point. Thecodont Saurians are both of Triassic and Permian age. " Hyperodapedon, Stagonolepis, and Telerpeton," says Professor Huxley, " had no stronger affinities with Mesozoic Reptilia than the Proterosauria (Permian), or than some of the Labyrinthodonts of the Coal have with those of the Trias "* ; Telerpeton, he has little doubt, was altogether terrestrial. Seeing that Hyperodapedon is as nearly allied to the living lizard Sphenodon as to its Triassic congener Rhynchosaurus, he sees no reason why it may not hereafter be " discovered in Permian, Carboniferous, or even in older rocks." With this I
- On Hyperodapedon (Quart. Journ. Geol. Soc, 1869, vol. xxv. p. 149).
