READING THE RIDDLES OF THE ROCKS 111 



of Kansas shows traces of the existence of long, soft 

 feathers on the legs and very clear imprints of the 

 scales and reticulated skin that covered the tarsus. 

 From the Chalk of Kansas, too, came the example of 

 Tylosaur, showing that the back of this animal was 

 decorated with the crest shown in Mr. Knight's restora- 

 tion, one not unlike that of the modem iguana. From 

 the Laramie sandstone of Montana Mr. Hatcher and 

 Mr. Butler have obtained the impressions of portions 

 of the skin of the great Dinosaur, Trachodon, which 

 show that the covering of this animal consisted largely, 

 if not entirely, of small, irregularly hexagonal horny 

 scutes, slightly thickened in the centre. Here again 

 time has proved helpful and two fairly complete, 

 " mummied" specimens of Trachodon have been found 

 by Mr. Charles Sternberg, in which a great portion of 

 the skin has been preserved. These animals apparently 

 died and shriveled up before they decayed. They were 

 then swept into water and engulfed in quicksand or else 

 covered with drifting sand. The quarries of lithographic 

 stone at Solenhofen have yielded a few specimens of 

 flying reptiles, pterodactyls, which not only verify the 

 correctness of the inference that these creatures pos- 

 sessed membranous wings, like the bats, but show the 

 exact shape, and it was sometimes very curious, of this 

 membrane. And each and all of these wonderfully 

 preserved specimens serve both to check and guide the 

 restorer in his task of clothing the animal as it was in life. 

 And all this help is needed, for it is an easy matter to 

 make a wide-sweeping deduction, apparently resting on 

 a good basis of fact, and yet erroneous. Bones of the 

 Mammoth and Woolly Rhinoceros, found in Siberia 

 and Northern Europe, were thought to indicate that at 

 the period when these animals lived the climate was 

 mild, a very natural inference, since the elephants and 



