RANGE AND EXTENT. 351 



course, are detailed in the descriptions of the general sections. We take pains not to 

 repeat, under this head, what is described in those connections. 



At Sunderland the quartz formation turns to the northeast, following the direction of 

 the great valley. It lies mostly away from points accessible by roads. At a saw mill 

 east of Factory Point in Manchester, east of A. Bourn's house, is seen the western limit 

 of this rock, in ledges of semi-vitreous quartz much jointed. At the toll gate in Winhall, 

 the rock is rather talcose in its appearance, lying in nearly horizontal layers. Following 

 the quartz rock nearly due north, through Dorset, Mount Tabor, and Wallingford, we 

 come to the "white rocks," a mountain composed of the first and second varieties of 

 quartz ; the strata dipping 70 W. on top of the mountain and about 30 W. at its base. 

 The slope is too great to permit the growth of trees, and the mountain stands out 

 distinctly to view, a naked rock, about 1,000 feet above Otter Creek. At its base are the 

 famous ice-beds, among the debris of mammoth blocks that have fallen from the mountain } 

 covering several acres. These blocks average four feet in diameter the largest being 

 twenty feet and present a curious landscape in connection with the white rocks, a scene 

 of magnificent desolation. Scarcely any plant except the leathery Umbilicaria can find a 

 foothold upon the fragments. That is wonderfully prolific. Between the white and 

 calico rocks, the eastern line of the quartz rock curves to the west, while that of the 

 gneiss curves also , and in this series the gneiss is found at a much lower level than the 

 quartz, which shows, we think, that the gneiss underlies the quartz rock, the overlying 

 rock having been removed from this series by erosion. If erosion be denied, though the 

 valley of a considerable stream crosses the formation, and has been worn down by the 

 stream between the white and calico rocks, the fact of the curvature is sufficient to show 

 that the gneiss was formed first, and that the quartz was deposited around the curve. 

 The distance between the arc and the chord of this curve must be about a quarter of 

 a mile. . 



The formation is mostly obscured by drift between East Wallingford and Chittenclen, 

 and more than an ordinary portion of it has been removed by erosion. Near Mendon 

 Post Office, upon East Creek, the quartz rock, quite slaty, -is exposed dipping 55 E. 

 Passing into Pittsford, there is a spur running from Blueberry Hill -towards the second 

 range of quartz rock in Rutland. The strata upon Blueberry Hill dip 40 W., as if it 

 passed under the Eolian limestone. It is not quite certain but that this spur of quartz 

 rock joins the smaller range and thus continues in a narrow belt to Danby, being associ- 

 ated during the southern part of its course with talcose schist. 



The only point needing investigation is this : does the rock at Blueberry Hill connect 

 with ledges in the northeast part of Rutland ? There is a district about a mile in length 

 that must be examined to answer this question. We have not ventured to connect them 

 upon the map because it is a point of so much consequence in the theoretical geology of 

 the State that we did not wish to state what had not actually been observed. 



Quartz rock is abundant at two localities half a mile southwest of Blueberry Hill. Two 

 miles from Blueberry hill it appears again, and in all these places it has its usual litho- 

 logical character. A high hill separates East Creek from Otter Creek, upon which we 

 wore informed this rock existed. We certainly should expect to find it there, because it is 

 found both north and south of it ; and the superior hardness of the quartz, preventing 



