648 STRATIGRAPHICAL GEOLOGY. 



overlaid both to the north and south by eruptive rocks, the Conway 

 granite on the former side, and porphyry on the latter. In passing near 

 Melvin peak the porphyry is found to succeed the gneiss of "Canaan," 

 and to occupy nearly the whole of this eruptive area of Ossipee. At the 

 Ossipee falls, on the west side, the Albany granite is found beneath the 

 porphyry in a thin strip, resting like a blanket upon the upturned edges 

 of the Lake gneiss. To the south of the mountain mass the dividing line 

 between the Montalban and Lake groups runs through Tuftonborough 

 corner. Between Ossipee falls and Center Harbor the section passes 

 through the typical region of Lake gneiss, and exhibits three important 

 flexures. West of the Center Harbor landing we find porphyritic gneiss, 

 with westerly dips. This has been already shown to be doubled like 

 the barb of a fish-hook ; and the range repeats itself, with fan-shaped 

 structure, in New Hampton. The Lake gneiss between has been forced 

 into a monoclinal attitude, with a small anticlinal just at its west border 

 north of White Oak pond in Holderness. After passing the porphyritic 

 gneiss, the Montalban succeeds through Bridgewater and Hebron, exhib- 

 iting no less than five foldings. The anticlinal of Peaked hill in Bridge- 

 water seems to be quite an important one. Fig. 82 covers nearly the 

 same ground with this section between the Ashland and Groton bands 

 of porphyritic gneiss. Another, on a parallel line to the south. Fig. 95 

 (p. 567), shows five foldings in the Montalban. North of Hebron village 

 we have the mica-bearing rock in its largest development. Groton, along 

 the section line, mainly consists of porphyritic gneiss, being the northern 

 end of the great central range, and exhibited only because Cockermouth 

 brook has cut down through the superincumbent formations. The west- 

 ern border of the porphyritic gneiss is thought to be overlaid unconform- 

 ably by the mica schist, the same with that in the north part of Hebron, 

 and is disposed as a double basin. This is underlaid on the west side 

 by the Lake gneiss, in a closely-pressed anticlinal dipping easterly. It 

 is supposed to underlie by inversion the porphyritic gneiss in the axis 

 between the micaceous basins just mentioned. 



Two bands of hornblende schist occur in Canaan, on the sides of a 

 synclinal mass of fine-grained Bethlehem gneiss. To the west of this 

 hornblende, cropping out near Goose pond, is an anticlinal mass of the 

 coarser Bethlehem gneiss, occupying all the space between the finer- 



