GEOLOGY AND GEOGRAPHY OF CLAY DErOSITS 



recent, as shown by the contained fossils, and the clay on Little 

 Neck near Northport is Cretaceous as previously noted. The 

 proof of the age of the Glen Cove clay is not absolute. 



Cretaceous leaves in fragments of ferruginous sandstone have 

 been found along* the north shore of Long Island from Great 

 Neck to Montauk Point,- but they are usually much worn and 

 scratched and have evidently been transported from some dis- 

 tant source. The clays at Center Island, West Neck, Fresh 

 Pond and Fisher Island are very similar in appearance and com- 

 position, are very probably of the same age, possibly Tertiary, f 

 but we lack palaeontology or stratigraphic evidence. At West 

 Keck the clay underlies the yellow gravel and the latter is 

 covered by the drift, so that is pre-pleistocene. 



The theory has been put forth that the Cretaceous formation 

 on Long Island would be found north of a line joining the southern 

 border of the Cretaceous formation of New Jersey and Martha's 

 Vineyard,;}; and that outcrops south of this might be Tertiary; 

 in view, however, of determining the clay at Little Neck near 

 North port to be Cretaceous, we must abandon this theory. 



Folded clays, West Neck, L. I. 



An interesting phenomenon is the tilting and crumpling of the 

 strata on the north shore of Long Island. This disturbance is 

 especially well shown on West Neck and was considered by 

 Dr. Merrill to be due to the pressure of the advancing ice 

 sheet,§ which excavated the deep narrow bays and pushed the 



* A. Hollick, Notes on Geology of North Shore of Long Island, Trans. N. Y. Acad. Sci., XIII. 

 t This idea is also expressed by Dr. Merrill. 



t A Hollick, No.es on Gleology of North Shore of Long Island, Trans. N. Y. Acad Sci. XIII. 

 § Geology of Long Island, Ann. N. Y. Acad. Sci. 1884. 



