562 STRATIGRAPHICAL GEOLOGY. 



Windham the gneiss dips north-west, and is speedily followed by a simi- 

 larly inclined mica schist of the newer series. 



Upon Section I this formation assumes the anticlinal form. The 

 western edge of the gneiss dips 50° N. 30° W. in the west part of Hud- 

 son. Near the east line it is incHned 85° N. 35° W., changing very soon 

 to S. 35° E., and just in the edge of Pelham, 87° S. 50° E. There is 

 a very fine exposure of gneiss, 75° S. 55° E., west of Compass pond. It 

 is followed by ledges of intermingled gneiss and granite, and by porphy- 

 ritic gneiss a little more than a mile south-west from Pelham village. 

 The granite of this town is like that of Salem, a stratified gneiss, with 

 some porphyritic crystals in it. After passing a wide alluvial tract, — 

 Beaver creek, — we find granites and slaty layers dipping north-west. For 

 two or three miles on the section line the dips are concealed. 



In the south-east part of Nashua are various gneisses not fully charac- 

 teristic of the formation. They are seen on the road nearest the state 

 line, about a mile back of the Merrimack, with a vertical vein of granite 

 one foot thick. They dip about 70° S. 20° E. The strata are much con- 

 torted. Near M. F. Sawyer's, a mile farther west, they dip 70° N. 50° W. 

 This is their western limit, save as they may be buried beneath drift. 

 This corner of the town shows us an anticlinal in the gneiss. 



We conclude there must be at least one anticlinal in this range, and 

 perhaps other folds. It is so well developed in Hudson and Pelham that 

 it is easy to believe it continues to the monoclinal section in Salem, and 

 the presumed anticlinal in Hampstead. The Merrimack group lies upon 

 both sides of it. Our studies of Massachusetts rocks lead us to call 

 gneisses very similar to this band, — and, in fact, the repetition of this one 

 beneath the Merrimack synclinal, — Laurentian. Should the Lake and 

 Laurentian series prove identical with each other, it would not be strange. 



The small area of similar gneisses and granites in Nashua may be the 

 same with this Pelham range. That follows the Nashua river from the 

 city to the state line, and perhaps further. It is quarried extensively a 

 short distance beyond the city cemetery. There is a fine opportunity at 

 the quarry to observe the strata. On the south wall there is a change of 

 color, one shade showing distinctly strata dipping 80° S. 35° E., and the 

 other simulating the granite stone. The latter seems to be the more 

 highly prized by the quarrymen. There appears to be little other change 



