GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 385 



50° N. 70° W. The same, with talcy seams, occurs in the valley of Clay 

 brook and at a school-house to the east, with probably no change in the 

 dip. Ferruginous schists occur next, up a hill. A very tough and ferru- 

 ginous hornblende rock crops out at Mrs. J. A. Whipple's, dipping 80° N. 

 W. No outcrops appear in the valley south-east ; but their strike leads 

 north-easterly to soft talcy schists, resembling hornblende superficially, 

 with the same position as the last, also, 46° N. 48° W. at J. Converse's. 

 At J. Hall's comes the narrow band of quartzite alluded to previously. 

 East of the quartzite, protogene gneiss occurs on Davison hill. 



This section differs entirely from that in Fig. 52, a distance of not 

 over four miles. Between them, on the roads passing Turtle pond, we 

 have chiefly the soft, green schists. On the Bass Hill road a mica schist 

 touches the gneiss, by A. English's, with dip of 70° N. 60° W. On the 

 north-east side of Acorn hill there is a greater resemblance to limestone, 

 at E. F. Cutting's. It is pyritiferous at J. and H. P. Stetson's. 



The next important section is given in Fig. 54, through Lyme and 

 Thetford. This afforded one of the typical sections of the original Coos 

 group, as published in the report for 1 870. We find layers of Bethlehem 

 gneiss and hornblende on the road to Smart's pond, the latter dipping 

 48° N. 60° W. north from E. Blaisdell's. Just east of the cemetery is a 

 band of quartzite, which is the eastern branch of the principal range, as 

 given upon the map. Between the cemetery and saw-mill, I found gneiss 

 like that common in Enfield village. The quartzite by the mill dips 85° 

 N. 70° E., and this is east of the crest of the mountainous range. Horn- 

 blende rock shows itself farther west, having the same position with a 

 strong band of vitreous quartzite, dipping 55° N. 62° W. The quartzite 

 seems to lie east of the road, after it bends to the south-west, near A. 

 W. Clough's ; and there occur, first, epidotic gneiss ; second, hornblende 

 rock, dipping 15° N. 30° E.; and by P. Allen's, where the road joins the 

 Canaan branch, limestone dipping 50°-6o° N. 70° W. Westward along 

 Grant brook extensive outcrops of Bethlehem gneiss show themselves, as 

 at L. Conant's and A. B. Dimick's ; but the position of the strata is not 

 easily ascertained. I thought, at my first visit, that Dimick's ledges au- 

 thorized the figures of 25° N. 48° W. I should say now the position had 

 better be made to agree with that of the limestone. The rock is unusu- 

 ally massive, planed down thoroughly by ice action, and simulates granite. 



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