322 STRATIGRAPHICAL GEOLOGY. 



quartzite with smaller dip ; sandstone, 70° N. 66° W. ; hornblende layer, 

 70° N. 62° W. ; and rock at Atwood's gold mine, 50° N. 72° W, 



As at present advised, the rocks north of Lisbon village may be thus 

 classified. At the railroad crossing is the Swift Water slate, continued 

 northerly from I. Clark's, which seems to point across the river to join 

 the ledges associated with the conglomerate west of Mrs. A. Bishop's. 

 Nearly two miles of exposure next are concealed by the meadows. A 

 little white quartzite, once thought to resemble Bethlehem gneiss, appears 

 by M. Kimball's ; then the Lisbon group as far as W. (not S.) K. Chase's 

 up the Ammonoosuc. These dip high north-westerly. As mentioned 

 on page 284, this area of Lisbon rocks seems to be disconnected v^ith 

 both the other ranges. The hornblende band succeeding dips N, 82° W. 

 beyond Chase's, and may be seen upon both sides of the river for some 

 distance. It occurs again at G. H. Buel's, upon Walker hill. I think that 

 is the branch proceeding towards Fitch hill, while that on the east side 

 of the river directs towards Streeter pond. (Compare with statement on 

 p. 284.) This hornblende band is thought to be Huronian. Next are 

 supposed Helderberg slates, dipping N. 50° W. just before reaching the 

 Whipple Brook road. Beyond that turn a short distance are calcareous 

 rocks 75° N. 42° W., followed by fossiliferous Helderberg strata 75° N. 

 32° W. Then there comes, by J. Dexter's, 2d., and D. S. Richardson's, 

 a series of micaceous limestones, green rocks, and conglomerates, having 

 the aspect of the Swift Water series, dipping N. 32° W. This brings us 

 nearly to North Lisbon, and the peculiar conglomerates and limestones 

 of the Helderberg group. 



These Swift Water rocks seem to be continued at eighty rods south of 

 W. Morse's house, — a white, soapy rock with quartz pebbles, the slate of 

 Walker hill used for whetstones, a ledge adjoining the Bethlehem group 

 west of D. Dexter's, and in general from this ledge across to the road 

 from Walker hill past W. Jackman's and Col. H. Richardson's into the 

 south part of Littleton. The ledges along this road dip 55° N. 32° W. 

 There is a fine development of them on a private road up to P. K. Corey's 

 in Littleton. Near his house the sandstone rock dips 70° N. 52° W. 

 South of the house the schistose rocks dip 75° N. 52° W., and there are 

 a large number of ledges. These Swift Water rocks are not seen farther 

 north-east, being covered by the alluvium. The Cambrian joins them 

 on the west. 



