SILICA. 



301 



The variety, actynolite, is found in bowlders at Corker's Hook, and in other places in the 

 southern part of the island.* The variety amianthus is frequently found in thin veins in 

 serpentine. The mineral formerly called Radiated asbestus, is the Hydrous anthophyllite of 

 Thomson. 



Orange County. This county is rich in hornblende, in almost all its varieties. The locali- 

 ties are principally in the towns of Cornwall, Monroe and Warwick. 



In the town of Cornwall, there is a locality four miles west of West-Point, and another four 

 miles southeast of Woodbury furnace. 



In the vicinity of Florida, there is a crystaUized green hornblende, which in its structure 

 resembles tremolite. 



In the town of Monroe, near the Two ponds, hornblende, occurs in the white limestone. 

 It is black and green. The crystals are sometimes six-sided and perfect, but they are most 

 generally rounded, and have a fused appearance similar to that exhibited by many of the 

 minerals in St. Lawrence county, and which is thought to favour the theory of the igneous 

 origin of white limestone. At the same locality, and elsewhere in this town, long four-sided 

 prisms of dark hornblende are found in trap. Near the Greenwood furnace, hornblende occurs 

 in six-sided prisms with dihedral summits ; and there is also, in the same vicinity, a black 

 shining granular hornblende. 



At the Stirling mine, crystal- 

 lized hornblende, of a dark green 

 colour, is found associated with 

 ilmenite in feldspar. There have 

 been obtained at this locality, the 

 dodecaedre, Fig. 226 ; and the oc- 

 toduodecimal of Haiiy, Fig. 227 ; 

 and modifications of the latter 

 form. The crystal represented in 

 Fig. 228, has also been found in 

 this town. M or M' on s 152° 

 17'; M'on x 117° 43'; k on k 

 55° 4'; A; on a; 102° 22'; r on r 

 149° 38'; rona; 105° 11'. 

 About a mile southwest of the Queensborough forge, there is a massive and cleavable va- 

 riety of a black colour, and having a high lustre. Some specimens closely resemble pyroxene, 

 and perhaps the two minerals pass into each other. 



A white lamellar variety is found associated with magnetic iron ore at the Stirling, and at 

 the Forest of Dean mine. It possesses a high vitreous lustre, and is traversed by striae. The 

 specimen which I analyzed approaches nearly the composition of Thomson's raphilite ; but 

 our mineral is not fibrous, and is much harder. 



Fig. 226. 



Fig. 227. 



Fig. 228. 



M 



•Gale. Nea-York Geological Reports, 1839. 



