1892.] NEW YORK ACADEMY OF SCIENCES. 41 



Considering these deposits geologically, we find that they may 

 be divided into tliree classes : 

 Quaternary, 

 Tertiary ? 

 Cretaceous. 



The first class is by far the most common. The second class 

 is still somewhat doubtful, but a large number of the Long 

 Island deposits probabl}^ belong to it. (F. J. H. Merrill, Geol. 

 of L. I., Trans. N. Y. Acad. Sci., Nov. 1884.) Of the third class 

 there are undoubted representatives on Long Island and Staten 

 Island, as well as some additional ones on Long Island that are 

 questionable. 



The clays of the mainland are all as far as known Quaternary. 

 The problems of the Quaternar}' formations in New York are by 

 no means solved, and it is not always possible to decide on the 

 causes leading to the deposition of any particular bod}' of clay 

 by a single visit to the locality, so that this paper must be con- 

 sidered as a preliminary one. 



A great majority of the deposits are small and basin -shaped, 

 lying in the bottoms of the valleys. They vary in depth fi'om 

 four to twenty feet ; as a rule they ai'e underlain by modified 

 drift or by bed rock. The claj is generally of a blue color, the 

 upper few feet being weathered mostl}' to a red. Stratification 

 is mostly wanting, although streaks of marl are common. In a 

 number of the beds small pebbles, usually of limestone, are 

 found, and these have to be separated by special machinery in 

 the process of brick manufacture. 



These basin-shaped deposits are no doubt the sites of former 

 ponds or lakes, fprmed in many instances by the damming up 

 of the valleys, and which have been later filled up by the sedi- 

 ment-laden streams from the glaciers. The valleys in Avhich 

 these local deposits lie are usually broad and shallow. In 

 many instances the clay is covered by a foot or so of peat. 



For convenience and clearness in describing the beds of clay, 

 the State may be divided into tliree divisions, exclusive of Long 

 Island and .Staten Island, which correspond pretty closely with 

 well-marked drainage areas. Only the more important deposits 

 u.nder each head are mentioned. 



Clays of the Erie, Ontario, St. Laivrtmce and Champlain Watershed. 



Thei-e are several localities along Lake Erie at which clays are 

 being worked. Chief among them is Buffalo. Around this city 

 is an extensive series of fiats underlain by a red clay, and several 

 similar deposits occur to the north of the old shore of Lake 

 Ontario. It is highly probable that during the former 



