350 KANGE AND EXTENT. 



This section is in the valley of Mad Tom Brook. This figure represents the position of the quartz rock 

 much better than Section IV. This is one of the clearest sections across this rock, that we have seen in 

 the State. Yet there are other sections, where the strata all dip in one direction, and the quartz beneath 

 the gneiss, so that we are perplexed to understand the true relation of the two rocks to each other. 



Under the present head we only present the facts respecting the position of this formation, reserving the 

 conclusions to be drawn from it for the last topic. 



Range, Extent and Thickness. 



The range and extent of this rock are quite simple. A band, never more than three 

 miles wide, enters the State in Pownal and takes a northerly course with minor curves, 



until it reaches Starksboro, where it termin- 

 ates. There is a smaller deposit, perhaps 

 connected with the principal one, leaving it 

 at Pittsford, and extending southwesterly to 

 Danby. 



Fig. 251 represents the position and char- 

 acter of this rock, in the southwest part of 



section of Quartz rock in Woodford. Woodford, on the old turnpike road from 



Bennington to Hartwellville. It is nearly 

 two miles long. No rocks are seen on this road, going east from Bennington, till the 

 "elbow" is reached. There the first specification is found, the supposed fossils being cavi- 

 ties in the rock, one-sixteenth of an inch in diameter, and cylindrical, filled with ferru- 

 ginous decomposed matter. An obscure vein of the Stamford granite was found in one 

 of the ledges. Were these abundant, we should have full evidence that the granite was 

 formed subsequently to the quartz. It is probable that before reaching the granite, the 

 quartz rock dips east, as in Clarksburgh, Mass. A few miles southeast of this section 

 (Fig. 251), drift covers the surface for at least two miles. 



If a thorough exploration could be made of the wilderness in the north and west parts 

 of Stamford, and the south part of Woodford, much of the obscurity which now perplexes 

 us might be removed. And yet it may be that the drift accumulations are so abundant 

 as to forbid the discovery of any ledges. This perplexed us in the central parts of 

 Woodford. The quartz rock continues north, forming the highest parts of the Green 

 Mountains, in the south part of the State. Mount Prospect, in the southwest part of 

 Woodford, is 2690, and Bald Mountain in the northeast part of Bennington, is 3124 feet 

 above the ocean. The formation thus bends a little to the northwest, in passing from 

 Woodford to Bennington. It even extends half way through the north part of the town, 

 and is quarried for building purposes, upon the land of Gen. Harwood. The west line 

 of the quartz rock is irregular through Shaftsbury. In the southeast part of the town 

 it has decomposed, but in such a way that the resultant white glass sand contains most 

 beautiful specimens of the Scolithus linearis. 



Cobble Hill is composed of jointed quartz rock. The high range of mountains in the 

 west part of Glastenbury is quartz, as its bald summits shining in the sun evidently 

 testify. 



The rocks of this formation in Sunderland are noticed in our remarks upon Sec- 

 tion III. The most interesting particulars respecting the quartz rock in its whole 



