642 STRATIGRAPHICAL GEOLOGY. 



where it is underlaid by inverted gneisses of the Montalban series. In 

 Stoddard this assumes the anticlinal form, followed by a synclinal in the 

 east part of Gilsum. This Montalban area terminates obtusely in the 

 north part of Stoddard. The west part of Gilsum is occupied by east- 

 erly-dipping strata of Lake gneiss. In the north part of Surry we cross 

 the narrow range of fibrolite schist carrying the very coarse granite 

 veins. This rock dips westerly at a high angle, and probably rests un- 

 conformably upon the Lake gneiss to the east in Gilsum, and upon the 

 Bethlehem group in the west part of Surry, the latter dipping easterly, 

 being almost vertical. Walpole is entirely composed of the Coos rocks. 

 The high hill west of the Ashuelot river exhibits mica schists, carrying 

 granitic beds with small westerly dips, running underneath the quartzites 

 along Fisher brook. Farther to the west the dips are higher, indicating 

 an antichnal, and hence the quartzite is older than the mica schists, but 

 made to assume the inverted attitude by the terrible crowding from the 

 east by the Gilsum and Surry gneisses. Just east of Walpole village are 

 ledges of argillaceous schists, dipping only 10° N. W. If these belong 

 to the Coos group, as seems probable, they would correspond to the 

 schist in the east part of the town, and are in their normal position. 



We have now reached the modified drift of the Connecticut valley, 

 which conceals the ledges for a considerable distance. In Westminster 

 we find the Cambrian clay slates, nearly vertical and inclined towards 

 the Walpole rocks. The few miles west of the river on this line have not 

 been directly traversed. The occurrence first of the calcareous rocks 

 west of the slates, and then of a narrow band of hornblende schist, over- 

 lying a large gneiss area, is well established by observations upon both 

 sides of the section line. 



Section IV. 



Section IV properly commences at Great Falls, passing through Som- 

 ersworth, Rochester, Barrington, Strafford, Northwood, Epsom, Chiches- 

 ter, the north part of Concord, Hopkinton, edge of Warner, Bradford, 

 Washington, Lempster, Acworth, and Charlestown to Connecticut river, 

 a distance of eighty miles. 



The rocks east of it in Maine for ten miles are believed to consist 

 exclusively of the Merrimack mica schist. Their stratigraphical position 



