DIVERSITY OF THE GLACIAL PERIOD 



763 



erable pyrite and muscovite. They were seen in four places on 

 the northeast shore, and their presence was inferred in as many 

 more by the large springs which occur along the line of parting 

 between this formation and the gravels above. On the east shore 

 the dark-colored older beds were seen at one place in the bluff 



Fig. I. — Section near middle of northeast shore of Gardiners Island, N. Y. (0) 

 black Cretaceous clay; (i) fine gray micaceous sand (Cretaceous) ; (2) old glacial 

 gravel; (3) red clay; (4) laminated yellowish-gray silty sand ; (5) Wisconsin glacial 

 deposits. Height of section, 60 feet. 



at the southern end of Tobacco Lot Bay, here likewise asso- 

 ciated with a fold. The white clayey sands, which characterize 

 the Cretaceous on Long Island, were seen in one place in the 

 bluff on Bostwick Bay. They show here in a small overturned 



Fig. 2. — Section on west side of the hollow which afforded the figure in sec. i. 

 About 200 feet farther west. The figures indicate the same beds as in Fig. i. 



fold. These beds, in the absence of definite proof of age, are 

 regarded as probably Cretaceous, and are so correlated. 



2. Old glacial gravel. — Overlying the older beds, and involved 

 in the same folds with them, are reddish glacial sand and gravel 

 which, where best exposed, have a thickness of 10 to 15 feet. 

 These beds are for the most part composed of iron-stained 

 quartz, very much disintegrated and in sharp angular pieces. 

 Intermingled with these are many pebbles and bowlders of mica 

 schist, hornblende granite, and granitite, some weighing several 

 thousand pounds. The larger of these compound rocks, while 



