386 STRATIGRAPHICAL GEOLOGY. 



This quartzite range seems to lie altogether u23on the ancient gneiss, and 

 does not connect at all with the mica schists in East Lyme. A band of 

 mica schist occurs next, about three fourths of a mile wide. There are 

 no outcrops in the valley; but about a mile north the dip is 70° N. 63° 

 W. Other observations near by give 60° N. 50° W., both of which may 

 represent the average position of this formation. It is succeeded by clay 

 slates, both garnetiferous and stauroliferous. In the eastern part of the 

 belt, or by a road-crossing of the stream, the dip is 50° N. 50° W. It is 

 about 30° at another crossing by a tannery. Farther west the dip may 

 be 35°-40°; and at the western limit of the formation, by A. A. Lam- 

 phere's, the position is 50° N. 40° W. These slates have thus a much 

 lower dip than the schists eastward. By D. Fales's and at the church, 

 just in the edge of the village of Lyme, the western quartzite range crops 

 out. From here to the river there succeed greenish, soft schists, with a 

 mineral much resembling chlorite. The dips observed are the following : 

 About 50° N. 60° W. just north of the village; 50° N. 68° W., slightly 

 calcareous, at a bridge at the south end of the village ; about the same 

 at numerous exposures for a mile and a half along Grant brook ; at its 

 mouth, hard mica schists, 50° N. 40° W. Similar ledges occur between 

 the brook and Gilbert's bridge over Connecticut river, the rock resem- 

 bling hornblende schist, though quite soft, and dipping 60° N. 30° W. 



In Vermont there is a band of Coos schists, like that in the north part 

 of Orford, and carrying steatite, near the Norwich line. Two outcrops of 

 the soapstone are represented upon the map. At the school-house west of 

 Childs's pond is a quartzite, constituting the west edge of the Coos rocks, 

 dipping 50° N. W. A band of these schists, in which staurolite and kya- 

 nite occur prominently, extends southerly over Oak hill till it is covered 

 by the sand of the Pompanoosuc basin. It is represented as extending 

 to the west of a hornblende range. West of this there is about a mile 

 width of the eastern slope of Thetford, underlaid by the characteristic 

 Huronian schists, dipping, in accordance with some observations in the 

 Vermont report, 80° E., and, by my own measurement, 80° N. 30° W. 

 Before reaching Thetford hill, the clay slates succeed, with south-easterly 

 dips. At Thetford Centre, and generally along the valley of Vershire 

 brook (or Pompanoosuc river), the rock is a micaceous quartzite, dipping 

 80° S. 50° E. This was at first placed with the Calciferous mica schist. 



