"^"^ THE NEW EVOLUTION "^^^^ 



of the tenants and of their victims. Other caves are 

 crevices in the rocks into which unfortunate creatures 

 fell or into which carcasses and bones were washed 

 by rains. 



In fossil bone deposits complete skeletons of any- 

 kind are very rare. Most deposits consist of detached 

 bones and broken fragments. 



In a locality in Bavaria very fine calcareous muds 

 were deposited in quiet lagoons behind protecting 

 reefs. These muds are now turned to stone which is 

 quarried for use in lithographic printing. In quarry- 

 ing this stone many fossils which are most remarkably 

 preserved have come to light, including the imprints 

 of the bodies of such delicate creatures as squid (fig. 

 45, p. 97) and jellyfishes, and of a feather of an an- 

 cient bird. In this locality the remains are those of 

 animals that flourished in the age called the Jurassic 

 which was a very long time before most of our modern 

 animals appeared. 



By far the most abundant of all fossils are the 

 remains of animals and plants that in the past lived in 

 the sea. It makes no difference where they live, 

 whether on the bottom or swimming freely in the 

 water, when sea creatures die and after the scavengers 

 have done their work the hard parts that are left col- 

 lect on the bottom muds or sands. Here they are 

 gradually covered up by gravel, sand or mud brought 

 down by streams and distributed by the currents of 

 the sea. 



Battered shells and various remains of other crea- 

 tures — just such as we see on the beaches of the present 



[94] 



