DESCRIPTION OF THE GENERAL SECTIONS. 65 1 



alban. It is believed the great anticlinal, causing the rocks to dip in 

 opposite directions, while those on each side are mostly inverted, takes 

 its course nearly along the state line, so that all the Maine ledges on this 

 section have the south-east, and those in Eaton, Madison, and Tamvvorth 

 the north-west, dip of this arrangement. On reaching the north part of 

 Tamworth the Chocorua group of granitic rocks is met with. The section 

 crosses the southern extension of these eruptive masses, protracted south- 

 erly from Mt. Chocorua. The view of the latter mountain in our colored 

 heliotype certainly suggests the presence of other groups besides this on 

 the north side of the pond, but I have no positive knowledge respecting 

 their possible occurrence. A range of Montalban succeeds, extending to 

 Weed's Mills, and thought to consist of a folded synclinal. The occur- 

 rence of Lake gneiss a little south of the section in Sandwich and con- 

 verging to a point, suggests its presence across the line of description 

 underground, thus producing an anticlinal division of the Montalban, 

 which may not necessarily show itself at the surface. Farther south the 

 gneiss shows three folds. In order to reach the Notch from Weed's Mills, 

 one may pass north of Guinea hill and over the Black mountain spur of 

 Sandwich Dome. We find here gneiss dipping north-west and north. 

 The west part of the town is occupied by a range of porphyritic gneiss. 

 Next is a synclinal of Montalban holding a large dyke of Albany granite, 

 and showing a slight recurrence of the porphyritic gneiss in the east part 

 of Campton, and quite fully in the Pemigewasset river. Between these 

 two ancient ranges we must conclude the monoclinal Montalban strata to 

 consist of an inverted synclinal. A similar easterly dip prevails west of 

 the Pemigewasset, before coming to the porphyritic gneiss of Ellsworth. 

 The latter consists of two folds, the most western occupying the slope of 

 Carr's mountain. In a basin near Ellsworth pond is a considerable band 

 of andalusite mica schist, either Montalban or later, perhaps connecting 

 related rocks in Rumney with others in Woodstock. On the summit and 

 west side of Carr's mountain the andalusite mica range occurs contiguous 

 to the porphyritic gneiss and dipping towards it. In Wentworth the 

 Lake gneiss has a full development, having a monoclinal east dip before 

 coming to Baker's river, and showing an anticlinal on the west side. An 

 isolated band of quartzite indicates an underlying gneiss basin in the 

 west part of the town. In Orford the prominent quartzite range of Mt. 



