26o NEW YORK STATE MUSEUM 



In southeastern New York there are siliceous magnesian lime- 

 stones which may be representative of the Beelcmantown, although 

 their exact position in the stratigraphic series has not been definitely 

 determined. They are especially developed in Orange, Westchester 

 and Rockland counties and are quarried at Tompkins Cove, Ver- 

 planck Point and near Newburgh. 



The Chazy limestone is exposed in discontinuous patches from 

 Saratoga county north to the Canadian boundary. It attains its maxi- 

 mimi thickness in eastern and northeastern Clinton county, and has 

 been quarried aroimd Plattsburg, Chazy, on Willsboro point, Valcour 

 island and other places. It is the earliest representative of the 

 Paleozoic limestones that has a fairly uniform and high calcium 

 content; the analyses show up to 95 per cent or more of calcium 

 carbonate. It has a grayish color and subcrystalline texture. The 

 fossiliferous beds yield attractive polished stone and are quarried 

 near Plattsburg for interior work. It is used for lime, furnace flux 

 and is adapted to portland cement manufacture. On the west side 

 of the Adirondacks, the Pamelia limestone, described in the reports ^ 

 by Cushing and Ruedemann on the areal geology of that section, 

 belongs to the Chazy series. It covers a considerable area in Jeffer- 

 son county between Leraysville and Clayton, and has been rather 

 extensively worked for building stone and lime. 



The Lowville, Black River and Trenton formations, of the 

 Mohawkian or Trenton group, are closely related in their features 

 and distribution. They rank among the very important quarry 

 materials of the State. They are represented in the Champlain 

 valley, but are especially prominent on the Vermont side; from 

 the latter area a belt reaches across northern Washington county 

 to Glens Falls in Warren county and is continued into Saratoga 

 county. Quarry openings in this section occur near Plattsburg, 

 Crown Point, Larabees Point, Sandy Hill, Smiths Basin and Glens 

 Falls. Portland cement, lime, building stone and crushed stone 

 are produced in the vicinity of Glens Falls. In the Mohawk valley 

 there is a considerable exposure of the limestones near Amsterdam 

 and north of there across the towns of Perth and Broadalbin, with 

 several quarries that yield building stone, crushed stone and material 

 for lime manufacture. The largest area of these limestones is the 

 belt which begins in the Mohawk valley near Little Falls and extends 

 northwest with gradually increasing width across Oneida, Lewis and 

 Jefferson counties to the St Lawrence river. Within its limits are 



1 See especially, Geology of the Thousand Islands Region, N. Y. State Mus. 

 Bui. 145, 1910. 



