584 STRATIGRAPHICAL GEOLOGY, 



similar nature and position elsewhere in the south part of Londonderry 

 and the north part of Hudson. On the route from Windham town hall 

 across to Nashua the following observations may be relied upon. The 

 schist first appears on the south-east edge of the formation, a mile west 

 of the hall, by J. Evans's, dipping north-westerly. There is a gneissic 

 appearing rock at the west town line, by a railroad station, and feldspathic 

 bands at Noah Robinson's and D. Clement's, in Hudson, with mica schists 

 between. Several other ledges occur on the route, all of them with north- 

 west dips. Under the bridge over Merrimack river micaceous grits dip 

 80° S. 30° E., and there must be a synclinal between the last two obser- 

 vations. The rocks in Nashua are more like the Merrimack group than 

 those in Derry. The reservoir rock, dipping 80° S. E., is an argillaceous 

 quartzite. This may be the southward continuation of the similar rocks 

 wdth slates at the drug mill, on the north line of Nashua, dipping south- 

 east. At an excavation in North Pine street is one of the feldspathic 

 bands, dipping 80° N. W., and carrying small oval patches of mica. Two 

 miles south of the post-office, at R. Godfrey's, mica schists dip 45° N. 33° 

 W. At the cemetery a mile north of the state line, next the Lowell rail- 

 road, the same rock dips 50° N. 20° W. A feldspathic band occurs a 

 mile north. Taking the route between the two gneiss areas to the 

 south-west, we find a hard mica schist with segregated veins at A. and C. 

 Lund's, dipping 75° S. E. Three miles out, on the Acton railroad, a cut 

 shows several varieties of mica and sandy schists, dipping 15° S. At L. 

 White's, near Lowell pond and the state line, is an unclean, coarse, ferru- 

 ginous mica schist, dipping 65° S. 60° E. Near S. Swallow's, feldspathic 

 mica schist dips S. 40° E. This section of the formation dips altogether 

 south-easterly. 



The more argillaceous member occurs east of H. Wood's, near the 

 west line of the town and north of the Nashua river, dipping 85° S. 30° 

 E. At Terrill's, near the town farm of Hollis, it is more slaty, dipping 

 45° S. 50° E. Near Hollis centre similar ledges, jointed and micaceous, 

 dip 50° S. 40° E. Proctor hill, in the west part of the town, is composed 

 of mica schist — dip, 45° S. 70° E. — and a large protrusion of the granitic 

 layer. On the western slope of the hill the schists dip 55° S. 80° E. 

 This rock is believed to occupy the south-east part of Brookline. In the 

 north-west part of Nashua, at B. F. Colton's, the schist dips south-east, 



