74 NEW YORK STATE MUSEUM 



is a fairly developed sheeting which dips 15° S. or nearly parallel to 

 the slope, and facilitates extraction of the blocks. This stone is a 

 little darker and more finely textured than at the other quarries 

 visited, due to the increased percentage of the biotite and horn- 

 blende. 



The quarry formerly worked by Gordon and Turcotte lies a little 

 south of Thurso. It is perhaps the one described by Smock as 

 situated about half i a mile from the northwest side of the island, and 

 known as the Gordon quarry. This was then operated by the Inter- 

 national Granite Company of Montreal. Gordon and Turcotte 

 ceased work about twelve years ago. 



The Potter quarry, now owned by H. B. Kelly, lies about a mile 

 southwest of Thurso and yields both red granite and a darker 

 colored rock which is perhaps related to the Adirondack syenite 

 but which was not seen in place. The latter stone is used for 

 monumental work. The quarry has not been developed to any 

 extent. The ledge is about 75 feet high and the quarry lands in- 

 clude 10 acres. 



THE PICTON ISLAND AREA 



The 'Picton Island Red Granite Company 



The characteristic Thousand Island red granite is obtained at 

 present in quantity only from Picton island, which yields medium- 

 grained to fine-grained varieties as compared with the prevailing 

 coarse granite of Grindstone island. Picton island lies about 3 

 miles north of Clayton, between Grindstone and Wellesley islands ; 

 it is called Robbins island on the United States Geological Survey s. 

 map, though known locally by the former name. The quarries are 

 on the northern end of the island, where the ledges rising directly 

 from the shore Hne afford a face from 50 to 75 feet high, almost at 

 the water's edge. There is little stripping or other preparation re- 

 quired, and the stone is loaded directly on boats from the quarries 

 for shipment to river and lake ports. Rail shipments are made from 

 Clayton, where the company owns docks and yards close to the 

 railroad. 



The Picton Island granite is a part of the same mass which out- 

 crops over most of Grindstone Island and the southern end of 

 Wellesley island. It is a closely textured, sound stone of attractive 

 color, taking a lustrous polish and well suited for building and 

 monumental work. Two varieties, medium-grained and fine- 

 grained are obtained, the former having a bright red body flecked 



