348 Geology of Long Island. 



In fact the whole deposit would seem to be the decomposition 

 product of a granulite rock such as occurs abundantly in West- 

 chester Co., N. Y., and in southwestern Connecticut. In the north 

 end of the bank is an nnconformability, the gravel beds, which 

 clip 37°, being overlaid by stratified sand dipping 15° in the same 

 direction. The layers shown in this section form the north slope 

 of an anticlinal flexure, the lowest beds being, I am informed 

 by Mr. Coles Carpenter, one of the proprietors, almost vertical. 

 An excavation made about 100 yards W. S. W. of the main pit, 

 for the purpose of obtaining some leaf-prints, exposed the fol- 



ing section : 





Gravelly drift, 



6 feet. 



White sand, - 



18 inches. 



Coarse " - - 



6 



Reddish clay, - - - 



- 2 " 



Grey sandy carbonaceous clay 





with leaf-prints, 



4 " 



14 feet. 



These beds dipped about 15° S. W T ., the locality being on the 

 south slope of the anticlinal. Owing to the sandy nature of the 

 clay, and the dryness of the season, no satisfactory specimens 

 could be obtained. The prints retain no carbon, but simply 

 show the venation of the leaves, 



North of Sea Cliff, along the shore of Hempstead Harbor, to 

 the Glen Cove steamboat landing, is a series of clay beds out- 

 cropping on the beach and dipping N. by E. about 10° ; these 

 beds are of various colors, blue, yellow, reddish, white and black. 

 The reddish clays contain fragments of a soft hematite, and one 

 of the blue layers is overlaid by about two inches of lignite in 

 small fragments. Other layers contain pyritized lignite and 

 nodular pyrites, but it is impossible to determine the nature and 

 order of these beds accurately, without extensive excavations. 

 Dark clays, with pyrites, are also reported to occur in Carpenter's 

 pits at a considerable depth. In the beds of decomposed gravel 

 already mentioned, are many geodes of sand cemented together 

 by hydrous and anhydrous sesquioxide of iron, containing a 

 dark granular mass which analysis shows to consist chiefly of 

 decomposed pyrites. The conclusion is therefore justifiable that 

 the nodules of marcasite which once existed in the gravel beds 



