288 STRATIGRAPHICAL GEOLOGY. 



The clay slates following rise up into a high wooded hill. The aver- 

 age dip of the whole formation is about 60° north-westerly, agreeing with 

 that shown on Fig. 28. The Lyman argillitic mica schist succeeds, dip- 

 ping at a steeper angle in the same general direction. A large bed of 

 quartz near the eastern edge has been opened, under the name of the 

 "New Hampshire Gold Mine." This band, though finely characteristic 

 of the Lyman series, is only about 1 100 feet wide upon the surface. Next 

 succeeds a width of Helderberg slates and limestones, estimated at eight 

 hundred feet. The exposures are well seen in the pasture south of the 

 road from the New Hampshire mine to that of the New England Mining 

 and Reduction Company. The Helderberg strata dip usually 75°-8o'' 

 north-westerly. The fossils are minute broken crinoidal stems and cor- 

 als. Intercalated masses of rock are like the adjacent Lyman schists. 

 These easily-destroyed strata have probably been kept in place by an 

 enormous mass of the auriferous conglomerate, three hundred and eigh- 

 teen feet wide, which afforded protection on the north-west side. This 

 mass is much greater than ordinary, and must have accumulated through 

 a doubling by lateral pressure. The whole of it lies in the south angle 

 between the two roads meeting at the Reduction Works mine. The con- 

 glomerate runs N. 48° E., and stands vertical. On the west side of it 

 are green and white schists, with a dolomite bed, probably altogether 

 belonging to the Lyman group. The dip is high north-westerly east of 

 the road ; but at the mine, perhaps two hundred feet to the west, the dip 

 is 35°-7o' south-easterly. The band of conglomerate — a stone's throw 

 to the north-east — dips 70° S. 65° E. 



There is at this point evidence of an extensive throw to the east. The 

 conglomerate would naturally continue directly from the edge of the Re- 

 duction Works mine to its development, a mile farther south ; but an 

 inspection of our map of the course of this rock shows that it has been 

 roughly broken apart, and pushed 11 60 feet farther east. Of course the 

 schists west of the conglomerate went with it. This great dislocation is 

 illustrated by the broken condition of the strata, both as seen in the 

 ledges, and as further developed by the working of the mine. The 

 change of the dip from that prevailing over the first mile of the section, 

 or that lying west of the clay slates, indicates here the existence of a 

 synclinal axis in the Lyman group. The dolomite and auriferous con- 



