GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 365 



eminence consists of dioritic and dolomitic schists, cut by large veins of 

 quartz. The dip is quite variable, perhaps the most prominent being 12° 

 S. 10° W. Others dip due south, and also easterly. On the west side 

 of the summit there is a south-east dip. To the north of the summit the 

 rock is more slaty, and inclined southerly. On the south-west side of 

 the mountain, at J. Woodill's, the rock is somewhat argillitic, dipping 48° 

 S. 55° E. 



Crossing Connecticut river, we find a north-westerly dip of 75° to the 

 Huronian schists at the south-west angle of the stream, and between the 

 mouths of two brooks. A similar position seems to pertain to the ledges 

 on the Claremont side, as seen from Vermont. A little north of Weath- 

 ersfield Bow post-office the rock is an indurated slate, dipping 80° N. 60° 

 E. From these observations we conclude, first, that disturbances of con- 

 tinuity are more common than usual; second, that the structure is anti- 

 clinal ; third, that the group is the Lisbon rather than the Lyman. 



Hornblende Sehist. A band of hornblende schist, forming as it were 

 the "connecting link" between the Huronian and Coos groups in this 

 district, may properly be described here. It seems to extend continu- 

 ously from Orford to Plainfield. Back of Orford street, on the hill, it 

 dips 65° N. 60° W. Another development of it is near the south-west 

 corner of the town, on Section VII. A mile and a half east of the north 

 bridge in Lyme (Fig. 53) this range appears, dipping 50° N. 70° W. It 

 passes southerly to the west side of Post pond. A similar rock, half a 

 mile south of Gilbert's bridge, probably dips 60° N. 30° W. This is some- 

 what associated with the soft, green talcy schists of the Coos group. This 

 range should properly strike across into the south-east corner of Thetford, 

 where immense accumulations of soil conceal the ledges. On the south 

 side of the Pompanoosuc river this rock makes the eminence known as 

 Blood mountain, on which is a copper mine, the cupreous schists dipping 

 N. 70° W. There is a similar dip at T. Tilden's house, at the south end 

 of the same mountain. The range crosses into Hanover at a bend of the 

 river below Pompanoosuc station, and crops out near the mouth of Slate 

 brook. There are ledges of hornblende dipping 40° S. W. near the out- 

 lets of the stream from the town farm and the small brook north of it. 

 Where the stream follows a ravine, above C. Houston's, this rock dips 

 about 30° N. W. adjoining the gneiss. Next is the large outcrop of the 



