392 NEW Y0KK STATE MUSEUM 



Examples of this stone in construction are seen in the Presby- 

 terian church, and in the Sherman Library building, and the 

 railroad depot in the town."* 



Keeseville. — The Ausable river, the boundary line of Essex 

 and Clinton counties, has at this place, and at the famous chasm 

 below the village, worn its bed down deeply into the sandstone, 

 and along its bank quarries have been opened in both counties 

 for local supply. 



The thin beds mike a fairly good flagging-stone. The heavier 

 beds yield good stone for ordinary wall work ; and a great 

 amount of it has been put into buildings in Keeseville. In color it 

 is gray- white. It is rather more granular and not as hard as the 

 Port Henry sandstone. 



Malone, Franklin County. — The sandstone of the Potsdam 

 horizon is opened by small quarries at this point, and at localities 

 to the west, but they are unimportant, and the next group to be 

 noted is at 



Potsdam, St. Lawrence County. — The formation is so well 

 developed in the valley of the Eaquette river, southeast of the 

 village of Potsdam, that it has been named the Potsdam sandstone. 



Thomas S. Clarkson's estate f and Mrs. Charles Cox,- the latter 

 operating under the name of the Potsdam Red Sandstone Com- 

 pany, have quarries along the river, at an average distance of 

 three miles, east-southeast of the village. The beds range in 

 thickness from a few inches to six feet, and afford blocks of 

 varying sizes. In most of the beds there is a more or less 

 laminated structure, especially in the darker-red colored stone. 



The color is light-pink, light-red or salmon colored, and red to 

 reddish brown, varying in the several openings. 



A representative specimen, taken from the company's quarry, 

 has a specific gravity of 2.604, equivalent to a weight of 162 

 pounds to the cubic foot. Its percentage of silica is relatively 

 large, and the cementing material appears to be silicious also. 

 The oxide of iron, as determined by analysis, is 0.36 (ferrous 

 oxide) in amount. 



* This quarry yielded the trails of trilobites upon ripple-marked beds, fine specimens of which 

 are in the State Museum, and the American Museum, New York. (See Forty-second Annual 

 Report, New York State Museum, pp. «5-29.) 



t A. Clarkson, Secy. 



