62 NEW YORK STATE MUSEUM 



width across Oneida, Lewis and Jefferson counties to the St Law- 

 rence river. There are isolated areas of Trenton limestone in the 

 Hudson valley south of Albany. The limestones vary in compo- 

 sition and physical character according to locality and geologic 

 position. They are often highly fossiliferous. In the northern 

 section they are mostly gray to nearly black in color, contain little 

 magnesia and run as high as 97 or 98 per cent calcium carbonate. 

 The lower part of the group is heavily bedded and well adapted for 

 building stone ; the upper beds commonly contain more or less shale. 

 They are used for various purposes including building and orna- 

 mental stone, crushed stone, lime, portland cement and flux. In 

 the Champlain valley quarries are found near Plattsburg, Larabee's 

 Point and Crown Point ; in Washington county at Smith's Basin ; 

 in Warren county at Glens Falls w r here there are extensive quarries 

 that supply material for building purposes, portland cement and 

 lime. The well-known black marble from Glens Falls is taken from 

 the Trenton. Numerous quarries have been opened in Herkimer, 

 Oneida, Lewis and Jefferson counties. The output of the last named 

 county is specially important, including limestone for building and 

 road construction and lime for manufacture of calcium carbide. 

 The principal quarries in Jefferson county are at Chaumont. 



The next assemblage of limestones in the order of stratigraphic 

 occurrence includes the Clinton, Lockport and Guelph members of 

 the Niagara group. The Clinton limestone has a variable impor- 

 tance in the belt of Clinton strata that extends from Otsego county 

 a little south of the Mohawk river across the central and western 

 parts of the State on the line of Oneida lake and Rochester to the 

 Niagara river. East of Rochester the limestone is relatively thin, 

 usually shaly and split up into several layers, but on the west end 

 in Niagara county it becomes the predominant member and has a 

 more uniform character. Large quarries have been opened recently 

 at Pekin, Niagara county, for the supply of flux to the blast fur- 

 naces of the Lackawanna Steel Co., at Buffalo. The upper beds 

 of bluish gray fossiliferous limestone from 10 to 12 feet thick 

 are the purest and analyze from 90 to 95 per cent calcium carbonate. 

 The Lockport is a magnesian limestone, in places a typical dolo- 

 mite, and is rather silicious in the lower part. It outcrops in a 

 continuous belt, several miles wide, from Niagara Falls east to 

 Onondaga county and then with diminishing width across Madison 

 county. The upper layers are rather heavy and yield material 

 suitable for building purposes, road metal and lime. There are 

 quarries around Niagara Falls, Lockport and Rochester. It is 



