GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 38/ 



Recent studies in Thetford and Fairlee lead to the opinion that this 

 quartzite may be the proper equivalent of the quartzite described as a 

 part of the Coos group, as in Hanover, etc. There is nearly as much 

 silica in the Thetford as in the Moose Mountain series, the first adding 

 mica in small proportion to the usual vitreous compound seen east of the 

 Connecticut. In agreement with this suggestion, I have colored quite a 

 large area west of the Cambrian slates as belonging to the Coos group. 

 It is worthy of notice that this formation carries the copper beds of Ver- 

 shire, and perhaps the pyrites of Copperas hill. It is represented as ex- 

 tending to meet the ancient gneiss in the west part of Hartland. Its 

 occurrence at West Hartford and to the south of Quechee village has 

 been particularly noted. The resemblance between these schists and 

 specimens from Littleton is very marked. 



In the south-west part of Lyme there is a large development of soft, 

 green schists, whose silicate mineral seems to be talc or chlorite. They 

 are well seen on the hill road to Hanover, between Grant and Fairfield 

 brooks. Without close inspection, one would be disposed to say the rock 

 was hornblende ; — in fact, some of my earlier notes give that name to it. 

 With it are occasional calcareous seams, so that it presents a resemblance 

 to the formation about to be described as the Calciferous mica schist in 

 Lebanon and Cornish ; and I have sometimes thought the Lyme area, as 

 well as much of the Hanover rock, should be regarded as Calciferous. 

 The position is uniform over this part of Lyme, except a dip of S. 50° E. 

 at C. C. Webb's. At N. Kendrick's it is S. 57° W. 70°; at S. Hewe's, 

 70° N. 80° W.; but farther north not more than 60°. Towards the Han- 

 over line, the rock becomes considerably ferruginous. At a bend in the 

 road by A. Smith's, in the north-west part of Hanover, the limestone is 

 present in the greenish schists, with a north-westerly dip. To the south, 

 we find the ferruginous schists of Spencer, Lord's, and Prospect or Pin- 

 neo hills, which have been noticed under the head of Bethlehem group 

 (P- 353)> and are more likely to belong to the Coos than the other series. 



The section in Fig. 55 shows the position of the layers from Bliss pond 

 and near the south line of Lyme to Union Village, Thetford. The quartz- 

 ite is wanting east of the pond; and the mica schists join the gneiss with- 

 out it a little west of J. Tyler's, south of Bear hill. Hornblende schists 

 are interstratified with them at A. Blood's, standing nearly perpendicular. 



