606 NEW YO-RK STATE MUSEUM 



to Montauk point/ but they are usiially mncli worn and scratclied 

 and have evidently been transported from some distant source. 

 The clays at Center island, West neck, Fresh pond and Fisher's 

 island are very similar in appearance and composition, and are very 

 probably of the same age, possibly Tertiary,^ but we lack paleon.- 

 tologic or stratigraphic evidence. At West neck the clay under- 

 lies the yellow gravel and the latter is covered by the drift, so that 

 is Prepleistocene. 



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 ISTew Jersey and Marthas 

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

 view, however, of determining the clay at Littleneck near !N^orth- 

 port to be Cretaceous, we must abandon this theory. 



An interesting phenomenon is the tilting and crumpling of the 

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

 specially 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 excavated material 

 into high hills at their head. Dr Merrill's views have been recently 

 corroborated in a paper on " The deformation of portions of the 

 Atlantic coast plain," by A. Hollick,* who, in disputing the possible 

 orogenic origin of these folds, calls attention to the fact that they 

 are found only along the line of the moraine, and that the beds are 

 disturbed only to a certain depth. The disturbance is well shown 

 at Glencove, West neck, Freshpond and on Fisher's and Gard- 

 iner's islands. It is important, however, not to confound tilting 

 of the layers, due to slipping, as is the case on Littleneck near 

 ISTorthport, with that produced by the ice-thrust. 



1 A. Hollick. " Notes on geology of north shore of Long Island," Trans. N. 

 T. acad. sci., 13. 



2 This idea is also expressed by Dr Merrill. 



3 " Geology of Long Island." Ann. 2V. Y. acad. sci. 1884. 



4 Trans. N. Y. acad. sci., 14. 



