Granites, Syenites and Gneisses. 33 



property is owned by George Marks, of West Troy. The opening 

 is a few rods west of the railroad line and a little way up on the 

 point of the ridge. The stone is properly a gneiss rock. It was 

 worked for a time, and some of the stone was sent to Albany for the 

 new capitol foundation. 



Adirondack Granite Company, Westport, Essex County.— 

 A granite quarry was opened in 1881 on the shore of Lake Cham- 

 plain and on the Splitrock tract, by the Champlain Granite and 

 Marble Company. Very little work was done that year. The 

 locality was reopened in 1887 by the present company. The quarry 

 is reported to be one-third of a mile from the wharf in Barron Rock 

 bay and at an elevation of 500 to 600 feet above the lake. The 

 specimens submitted to Prof. Hall in 1881, were reported by 

 him to contain labradorite, hornblende, quartz and a small pro- 

 portion of dark-brown mica.* The stone is said to receive a good 

 polish, and a monument in the Middlebury, Vermont, cemetery 

 shows that it retains the polish. The quarry is two and a half 

 miles from the line of the D. & H. C. Co.'s N. Y. & Canada railroad. 



Au Sable Granite, Essex County. — The quarries of the Au 

 Sable Granite Company are on the north slope of Prospect Hill, one 

 and a half miles south of Keeseville, and in Essex county. There 

 are two openings, a little more than 100 yards apart. They were 

 made in ledges whose surfaces were glaciated. The lower quarry is 

 to the northward, and has a maximum depth of 20 feet. The 

 joints which appear in the rock at this place are smooth and irregular. 

 One runs south 55° west. The others are not so regular. Another 

 system of joints runs south 10° east. The rock at this quarry is 

 coarser in crystallization than that of the upper quarry. The mineral 

 composition is labradorite, hornblende, quartz and here and there a 

 scale of brown mica. The weathered rock has a light-gray shade, due 

 to the alteration of the feldspar in the long ages since the close of 

 the glacial epoch. 



The upper quarry is about twenty rods south 10° west of the 

 lower, and is at least 100 feet higher up on the hill. The original 

 surface was steeply sloping north-west, and the earth covering was thin. 

 One main set of joints is vertical, and runs south 40° west. A 

 second one dips in the same direction. A third has a south-easterly 



*Report to company in their circular. 



