o,S NEW YORK STATE MUSEUM 



the Adirondack*, the green syenite which is found in various sections 

 as larger or smaller intrusive masses, and the light gray anorthosite 

 which constitutes the great central core of the mountains and is 

 exposed in outliers to the north and east of the main area. Some 

 of the more accessible and important localities for these materials 

 will he described. 



St Lawrence river granites. The red granite of Grindstone, Pic- 

 ton and Wellesley islands in the St Lawrence river is one of the 

 characteristic products of the region, widely known as an excellent 

 building and monumental stone. It ranks with the hest native 

 granites of its kind. The several exposures on the group of islands 

 between Clayton and Alexandria Bay belong to a single large but 

 irregular mass which in the recently issued geological report cover- 

 ing that section is described and mapped as the Picton granite. In 

 general it is a bright red coarsely textured granite in which the pre- 

 dominant ingredient is feldspar in large red individuals, with quartz 

 and biotite. Most of the product in earlier years came from Grind- 

 stone island which furnished large quantities of structural and 

 monumental material to the cities on the St Lawrence and the Great 

 Lakes. Paving blocks were also made in quantity. These quarries 

 are now idle or worked only in a small way. They are situated 

 mainly along the western shore of the island. The quarry of the old 

 Chicago Granite Co., now owned by H. B. Kelly of Clayton, has 

 been more active than the others of late and has furnished stone 

 for many of the structures along the river. The Forsyth quarry in 

 the same vicinity supplied the large columns erected in the Senate 

 chamber of the Albany Capitol. Though of coarse texture the stone 

 has excellent polishing qualities. 



The principal quarry operations in the area are now carried on by 

 the Picton Island Red Granite Co.. whose property is situated on 

 the northern end of Picton island, between the larger Grindstone 

 and Wellesley islands. The company has three quarries opened in 

 the natural ledges which rise directly from the shore line to a 

 height of 50 or y^ feet and which afford great advantages for 

 economic work. The output as it comes from the quarries or from 

 the cutting yards can be loaded directly on boats for river and lake 

 shipment. Rail shipments are made from Clayton where the com- 

 pany has its own docks and yards. The granite is of finer texture 

 than that from Grindstone island ; two varieties are obtained, one 

 with a medium grain and red body flecked witli black and the other 

 of finer grain with a uniform pink tint. The latter finds special 



