42 TRANSACTIONS OF THE [DeC. 5 



extension of the Great Lakes many of these clays were deposited. 

 They contain in many instances limestone pebbles. A thin layer 

 of yellow sand, suitable for tempering, often overlies the clay 

 around Buffalo. 



An extensive bed of clay of a red and grey color and horizon- 

 tally stratified occurs at Watevtown. It is one of the few of 

 which an analysis has been made, and it is here given. 



100.00 



The bank is some twenty feet thick and rests on Trenton 

 limestone. 



A deposit of considerable thickness occurs at Ogdensburgh. 

 The clay is of a blueish color, the upper ten feet being some- 

 what sandy. A depth of GO feet of clay has been proven. At 

 places it is found to be underlain by limestone. 



At Madrid, in St. Lawrence county, is a small deposit, proba- 

 bly the remnant of a formerly extensive one, in which the sec- 

 tion is, 



Yellow stratified sand ... 3 feet. 

 Blue clay with shells . . . 1 foot. 

 Blue clay 20 feet. 



Total thickness .... 24 feet. 



The shells are probably Miicomafasra. 



The clay beds along Lake Champlain are estuary formations 

 of the same age as those along the Hudson Valley. Openings 

 have been made in them at Plattsburg, Essex, and a few other 

 localities, but owing to the lateness of the season when I visited 

 them information was hard to obtain. 



Clays of the Mohaiok and Hudson River Watershed. 



Deposits of common brick clay are found at many points along 

 the line of the New York Central Railroad from Syracuse to 

 Schenectady. They are used at many points for the manufac- 

 ture of brick and tile. 



Very interesting are the Hudson River clajs. They are estu- 

 ary deposits and extend from Croton more or less continuously 

 up the Hudson Valley to Glens Falls and westward to Schenec- 

 tady. These clays were deposited during a post-glacial sub- 



