EXTINCT ANIMALS 



you see its seal stamped as it were on the sand. 

 It is many millions of years old, from Oolitic 

 rock. 



Now let us look at the layers or the strati- 

 fication of rocks. This picture (Fig. 33) shows 

 part of the cliff at Lyme Regis, where the 

 Ichthyosaurus-head, which I showed you just 



Fig. 32. — A Jelly-fish (similar to the recent Aurelia aurita) 

 preserved in Lithographic limestone. 



now, was found. We see the layers of harder 

 and softer material lying one over the other. 

 The next figure (Fig. 34) shows how the layers 

 of the surface of the earth may be bent. With- 

 out digging far into the earth you may reach 

 a deep layer of stratification or " stratum " 

 brought near the surface by the general tilting. 



4S 



