20 ANCESTORS OF iMAMMALS 



a combined rhinoceros and elephant. Its legs were long, 

 its feet covered with thick pads, the eyes deeply set ; and 

 in the upper jaw it had two caninelike teeth, or tusks. 

 This monster was twelve feet in length, with a body resem- 

 bling that of an elephant; its head was like that of a rhi- 

 noceros with the saberlike tusks of a tiger. It had two 

 large rhinoceroslike horns with two smaller ones below, 

 while on top of the head rose a pair of tall prominences 

 like the covered '' horns " of a giraffe. About thirty or 

 more forms of these strange creatures have been found, 

 the late Professor Marsh of Yale University having made 

 a special study of them, with results that can best be seen 

 at the Yale Museum. 



These wonderful creatures are known to have wandered 

 along the tropical lakes of Wyoming, browsing amid rich 

 and luxuriant herbage. What a contrast to-day ! By some 

 marvelous change this location is now far from tropical 

 and is in part a desert. Some fearful catastrophe seems 

 to have occurred, and what a few million years ago was a 

 garden is to-day a desert, and what was once a vast 

 inland lake is now on the crest of the continent, a jumble 

 of broken strata tossed, bent, broken, a maze of buttes 

 painted in fantastic colors, rising like ruined castles, a pic- 

 ture of sedimentary ruin. 



All this marvelous series was deposited at the bottom of 

 some lake, and in the soft mud the hard parts of the va- 

 rious animals that Hved during that time have been pre- 

 served. By some marvelous cataclysm the old lake beds 

 were tossed upward; they hardened in the suns of an 

 eternity; then began their demolition by wind, rain, and 

 snow. The deposit was cut by floods, rent in every way, 



