THE DIVERSITY OF THE GLACIAL PERIOD ON LONG 



ISLAND.' 



As POINTED out by Professor Shaler some years ago, the 

 region between, and including, northern New Jersey and Cape 

 Cod is admirably situated for the preservation of the records of 

 the glacial period.'' The work of Woodworth on the New Eng- 

 land islands has brought forth the complexity of the glacial rec- 

 ords there, and the results of the last field season on Long Island 

 and Gardiners Island have connected this work with that of Salis- 

 bury in New Jersy and given a basis for a tentative correlation 

 with the deposits of the Mississippi valley. 



GARDINERS ISLAND. 



Gardiners Island, situated between the two eastern flukes of 

 Long Island, presents many of the features shown on Nantucket, 

 Marthas Vineyard, and Block Island. The succession is essen- 

 tially the same and the correlation evident. It therefore forms 

 a ready point of reference between Long Island, on the one hand, 

 and the New England islands, on the other. 



The structure of the island can best be worked out on the 

 northeast shore, where the bluffs are quite high and are kept 

 clean by the constant encroachment of the sea. Here the suc- 

 cession of strata is : 



4. Gravelly till (Wisconsin). 



3. Interglacial clays and fossiliferous sands. 



2. Glacial gravel and bowlders. 



I. Black lignitic clay and white and gray to red sand (Cretaceous). 



The first three beds are very much folded and the last one 

 deposited irregularly on their eroded folds (Figs, i and 2). 



I. Cretaceous. — The older beds appear only in a few places 

 where they have been brought up by folding. They are com- 

 monly black to dark gray clays and very fine sands with consid- 



' Published by permission of the director of the United States Geological Survey. 

 "U. S. Geological Survey, Seventeenth Annual Report {\%()b), Part I, p. 957. 



762 



