Animals Before Man 



as the body decayed. But when some unusu- 

 ally fine specimens came to light in Germany, 

 specimens so perfect that they showed the very 

 texture of the skin, it was learned that the tail 

 was just the reverse of that of a shark, and the 

 back-bone actually ran down into its lower part. 



Like so many other animals, ichthyosaurs 

 started in the Trias, but while they developed 

 to such an extent in Europe as to form a char- 

 acteristic and striking feature of the life of the 

 Jurassic, here their career seems to have ended 

 abruptly, for they do not pass beyond the 

 Trias. They were apparently quite as restricted 

 in space as they were in time, and the only ich- 

 thyosaur remains yet noted in this country 

 came from the rocks "near Mount Shasta, Cal- 

 ifornia, whence Professor Merriam bestowed 

 upon them the generic name of SJiastasaurus. 



One very good reason for the seeming scar- 

 city here of many animals that were at this 

 time abundant elsewhere is the small extent of 

 our fossil-bearing Permian and Triassic rocks. 

 During these periods of the world's history a 

 large part of the present continent was above 



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