Now began an extremely interesting search for this new fauna in Kansas. The rocks in this part of the state usually consist of gray sand cemented together with washed chalk and soluble silica. The foundation on which these beds were deposited is the Niobrara Group of the Cretaceous. The river beds were cut in this soft lime, and later on the wash of the land mingled the whiting with the sand and gravel which the streams brought down from the mountains. The tops of the hills are capped with this conglomerate gray sandstone in ledges many feet in thickness, and as the materials composing it easily disintegrate, great masses of it lie at the bases of the cliffs, resembling old mortar. I called them mortar beds, and the stratigraphers have adopted the name. Indeed, they are mortar beds not only in name, from a fancied resemblance to mortar, but in fact, as all the early settlers can testify. It was no trouble for them to find beds so soft that the material could easily be dug out, and when mixed with water and spread with trowels over the inside walls of a sod house, it made a very comfortable home. When it comes to comfort, the settlers of the short-grass country have gained nothing by building frame instead of sod houses. The early settler’s sod house was cool in summer and warm in winter, and those who live in more modern houses in order to keep up with the times will even now speak with regret of the change.
FIG. 22.—FOSSIL SHELL OF GIANT LAND TURTLE, _Testudo orthopygia_.
Discovered by Charles Sternberg in Phillips Co., Kansas. ]
FIG. 23.—THE SNAKE-NECKED ELASMOSAURUS, _Elasmosaurus platyurus_.
Discovered in the Niobrara Group of the Cretaceous. Restoration by Osborn and Knight. (From painting in American Museum of Natural History.) ]
Not only did I secure a number of specimens of these great turtles, so abundant at this time, but also large quantities of the remains of a rhinoceros. Cope thought it hornless, and named it _Aphelops megalodus_, but since then Hatcher has found that the male bore a loose horn on the end of the nasal bones.
I also got specimens of the great inferior tusked mastodon, _Trilophodon campester_ Cope. This remarkably primitive mastodon had a lower jaw that projected beyond the molar teeth for two feet in a straight line, with a socket on either side, containing two powerful tusks that terminated in chisel points. One specimen, which I discovered in 1882 for the Museum of Comparative Zoology in Cambridge, had a jaw four feet long, including the tusks, which extended eighteen inches beyond the end of the jaw.