78 NEW YORK STATE MUSEUM 



vation in the vicinity. The bare rock is exposed on all sides of the 

 knob which has a diameter in a northeast-southwest line of about 

 one-fourth of a mile. A little bay sets in close to its base and 

 forms a natural harbor accessible to river boats, which afford the 

 only means of shipment. The main workings are on the east side 

 where there is a cut 200 feet long. Smaller openings have been 

 made on the top and north side. 



The granite is well jointed, the main courses being N. 30 W. 

 and N. 6o° E. An indefinite sheeted structure appears in places. 

 The structure and situation facilitate quarry operations and the 

 only drawback is incident to the somewhat variable character of 

 the stone which unfits much of it for anything but rough work. 

 Two shades of granite appear in the quarries, one having a light 

 gray color and the other a pinkish tint. Both varieties have the 

 same composition and texture. 



Microscopic examination. The appearance of the rock under 

 the microscope is that of an originally rather coarse granite which 

 has become finely textured through crushing and recrystallization. 

 The process has not effected in this instance any noticeable parallel 

 alignment of the minerals, but they show a compact arrangement 

 conducive to strength. 



The mineral composition indicates a biotite-muscovite granite of 

 normal character. The feldspar is mainly of the alkali kind repre- 

 sented by mkrocline, microperthite and orthoclase supplemented 

 by more or less lime-soda feldspar which appears to be oligoclase. 

 It carries quartz inclusions and has a broken corroded appearance. 

 Ferric oxide distributed along the fracture and cleavage planes of 

 the feldspar is the coloring agent in the pink granite. The micas 

 have only small representation and there is little magnetite or other 

 accessory minerals. 



Physical and chemical tests. In response to a request, Messrs 

 J. Leopold & Company contributed the following data relative to 

 physical tests of the granite which were made by the division of 

 tests, United States Department of Agriculture, in Washington. 

 The specific gravity is 2.65, corresponding to a weight of 165 pounds 

 a cubic foot. Three cubes approximately 3 inches on a side were 

 tested. Cubes no. 1 and no. 3 showed a strength of 17,780 pounds 

 and 17,570 pounds respectively, for each square inch of cross sec- 

 tion, or 20,860 and 22,220 pounds respectively for each square inch 

 of bearing surface. Cube no. 2 resisted crushing to the breaking 

 power of the machine. 



