GEOLOGIC FORMATIONS OF NEW YORK 175 



The Tertiary of our Atlantic slope consists chiefly of sands and 

 clays, which in the southern states are well developed. A much 

 larger development occurs west of the Mississippi river on the 

 sites of extinct Tertiary lakes. Marine Tertiary is also found on 

 the Pacific coast. 



In New York state the Tertiary is not accurately identified and 

 is indivisible, but is probably represented by sands and gravel 

 on Staten Island and Long Island. There is comparatively little 

 marine Tertiary in North America, as the northern part of the 

 continent was out of water at that time. The Tertiary beds west 

 of the Mississippi are chiefly fresh water deposits formed in lake 

 basins. The Tertiary was a period of mountain making. In 

 southern Europe the great chains of mountains known locally 

 as the Pyrenees, Alps, Apennines and Carpathians, consist to a 

 large extent of Tertiary rocks. This is also true of the Himalaya 

 mountains of India. It is known that extensive disturbances 

 in our Appalachian system occurred during the Tertiary. 



Life of the Tertiary period 



Birds and mammals succeeded the reptiles of the cretaceous. 

 Of the mammals all the orders now existing were represented. 

 Reptiles were not more numerous than at present and were simi- 

 lar to existing genera. Fishes were very abundant. Insects 

 were many and varied. Mollusks were abundant; oysters oc- 

 curred in great variety and of enormous size- Corals were not 

 plentiful. Land plants were very abundant and very similar to 

 those of the present day; the cypress grew in the Arctic regions. 



QUATERNARY SYSTEM 



At the close of the Tertiary a cold temperate climate reigned 

 in the United States and a great ice age began, during which the 

 northern part of our continent was covered with a sheet of ice 

 many hundred feet thick. The chief evidences of this are the 

 inscriptions of the continental glaciers on the rocks in the shape 



