ECONOMIC GEOLOGY 



209 



these deposits lie are usually broad and shallow. The broad flat 

 valley in which the Genesee river flows from Mt Morris to Ro- 

 chester is a gooidl example. The waters of the river were backed 

 up by the ice for a time, during which the valley was converted 

 into a shallow lake in which a large amount of aluminous mud 

 was deposited. This material has been employed for common 

 brick. 



Around Buffalo is an extensive series of flats underlaid by a 

 red clay. A thin layer of sand suitable for tempering overlies 

 the clay in spots, and ilimestone pebbles are scattered through it. 

 Similar deposits; occur at several localities to the north of the 

 Ridge road and around Niagara Falls, also at Tonawanda and 

 La Salle, to the north of Buffalo, as well as south of it along the 

 shore of Lake Erie. No douM much of this clay was deposited 

 during the former extension of the Great Lakes. 



Prof. James Hall mentions deposits of clay at the following 

 localities: at Linden, one mile south of Yates Center; "along the 

 shore of Lake Ontario, east of Lewiston; on Cashaqua creek 

 ^deposits of tenacious clay due to the crumbling of the argill- 

 aceous green shales; in Niagara county c beds of clay are said to 

 occur in every town, but they often contain a considerable 

 amount of lime. 



At Levant, four miles east of Jamestown, Chautauqua county, 

 is an interesting bed of blue clay having an area of several 

 acres. It is probably of post-glacial age. 



At Breesport, near Elmira, is a bank of blue clay rising from 

 the valley to a height of 50 feet. It was evidently formed when 

 the valley was dammed up, and has subsequently been much 

 eroded so that all that now remains is a narrow terrace along the 

 iside of the valley. A similar deposit is found at Newfield, south 

 of Ithaca. A moraine crosses the valley a mile or two south of 

 it. 



o Geology of New York, 4tb District, 1843, p. 437. 

 6 Ibid., p. 227. 

 elbid., p. Hi. 



