1892. | NEW YORK ACADEMY OF SCIENCES. 4] 
Considering these deposits geologically, we find that they may 
be divided into three 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 probably belong to it. (F.J.H. Merrill, Geol. 
of L. IL, 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 Quaternary 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 body 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 from 
four to twenty feet ; asa rule they are underlain by modified 
drift or by bedrock. The clay is generally of a blue color, the 
upper few feet being weathered mostly toared. 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, formed 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 which 
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 three divisions, exclusive of Long 
Island and Staten Island, which correspond pretty closely with 
well-marked drainage areas. Only the more important deposits 
under each head are mentioned. 
Clays of the Erie, Ontario, St. Lawrence and Champlain Watershed. 
There 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 flats 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 
