86 BROWN SANDSTONE, OR GRANULAR QUARTZ. 



Stamford, it is found to rest directly upon granite : this fact I ascertained as early as the 

 year 1828. Inunediately south of this heavy mountain of quartz, in the direction of its 

 strike, is the west ridge of Saddle mountain, composed of Magnesian slate and Stockbridge 

 limestone ; but three or four miles directly west of this ridge, is Stone hill, a less important 

 mass of quartz, surrounded as it were with limestone. The large mountain first spoken 

 of, and known as Oak hill, is evidently east of the limestone and other members of the 

 Taconic system at this point ; but Stone hill is west of the main bed of limestone, and is 

 also bounded on the west by a narrow belt of limestone which lies against the quartz, as 

 if the quartz was pushed up through it. The Stone hill range crops out about three- 

 fourths of a mile farther north, but attenuated, more slaty and of a darker color. ^ On the 

 south, again, there is no mass of quartz known which can be considered as belonging to 

 the Stone hill range. South mountain, in South Williamstown, which is directly in the 

 strike of Stone hill, is composed of magnesian slate and limestone. We are, therefore, 

 unable to trace this range continuously. The east range of which Oak hill is an impor- 

 tant part, appears south in Cheshire, and there forms immense quantities of siliceous sand 

 suitable for glass and for sawing marble; also in Dalton, at the gulph, and at the west 

 base of Washington mountain southeast of Pittsfield. It is continued in Lee, Tyringham, 

 Stockbridge and Sheffield ; in Dutchess county (New-York) , in Amenia and Dover ; and 

 in Putnam and Westchester counties, at numerous points. To the north, the eastern 

 mass appears in mountain ridges in Bennington and Arlington. But how far north this 

 rock may be traced, I am unable to say. That it is prolonged to a great distance I have 

 reason to believe, from facts stated to me by Prof. Renwick, who, while in the employ of 

 the Government in tracing the new provincial lines between the United States and Canada 

 East, passed over heavy beds of siliceous rocks, which, from the characters given of them, 

 I deemed could be no other tlian the Granular quartz. In the northern part of Vermont, 

 in the direction of Troy and Lake Memphremagog, I did not observe this rock, either in 

 beds, or detached masses forming boulders. The most interesting fact to be observed in 

 these details, is the unexpected and sudden disappearance of a rock which sometimes 

 occurs in masses a thousand feet thick ; not by attenuation, as in many other instances of 

 disappearance. The phenomenon may perhaps be resolved on the supposition that they 

 have been engulphed ; or perhaps the elevation of the ranges have been unequal : in one 

 place the quartz, limestones and slates were brought up, and the superincumbent lime- 

 stones and slates swept off, leaving the quartz exposed ; in others, the elevation was never 

 sufficient to expose the quartz at all : in the latter case, the only rocks at the surface are 

 the slates and limestones, one or both. 



