94 GEOLOGY. 



The PLEIOCENE FORMATION* is subdivided into the 

 older and newer Pleiocene. The older Pleiocene comprises 

 the Crag formation when not referred to the Meiocene. 

 This crag is of two kinds, the Red and the Coralline, 

 and is a marine formation. These crags are composed of 

 sand and marl and comminuted shells, and sometimes 

 are used as a building stone. The Newer Pleiocene 

 consists of strata of sand, clay, and marl. Deposits of 

 this nature are found in Cornwall. 



In this series are found the remains of numerous 

 animals ; of some whose species are extinct, and of others 

 which are still in existence. Of the extinct kind, the 

 .Dinotherium is the largest. This monster was from 15 to 

 18 feet in length, and 12 feet high, and its lower jaw was 

 four feet long. It had two tusks of immense size. The 

 use of these tusks was probably to dig up roots and 

 herbage. It chiefly inhabited freshwater lakes and 

 rivers. The Megatherium was another remarkable ani- 

 mal, somewhat allied to the sloth or ant-eater. Its 

 body was 12 feet long, and 8 feet high, its feet were a 

 yard long, "with gigantic claws. It had a tremendous 

 tail, so that with a single blow it would possibly have 

 killed a lion or a tiger of the present day. It fed on 

 vegetable productions. 



The Mammoth, a species of elephant, has been found, 

 14 feet long, and 9 feet and a half high, with tusks 9 

 feet long. Remains of this animal have been discovered 

 in various parts of Europe, also in America, but they are 

 no where so abundant as in the northern part of Asia. 

 In an island in the north of Russia, the tusks of this 

 animal have been found in such abundance, and so 

 perfect, that, for more than a century, they have proved 

 a valuable article of traffic. They are used for making 

 ivory goods. 



Of the Diluvial and Alluvial Deposits. 



Over the uppermost of the Tertiary strata, there are de- 

 posits consisting of gravel, sand and clay formed from the 



* Pleiocene, from Xi;<u greater or more, and x<of new. 



