GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. 1 29 



much greater in many places. Passing over into Maine, the rocks of the 

 Montalban group, where they were seen in Stoneham and Lowell, have a 

 westerly dip, generally at a small angle. 



West of Chatham in Jackson, Double Head is granitic gneiss, probably 

 an extension of the Montalban southward from the Dearborn & Philbrook 

 sav/-mill, but it is limited southward by the intrusive rocks in the south 

 part of Jackson and in the edge of Bartlett. 



Valley of the Ellis river. From the height of land in the Pinkham 

 notch southward to Jackson village, the White Mountain gneisses are 

 the prevailing rocks. Though the inclination of the strata is everywhere 

 westerly, yet the dip is quite variable. At Glen Ellis falls the dark gray 

 gneiss dips N. 60^ W. 45^ and N. 83° W. 60°. At the head of the falls 

 there is a wide quartz vein that is metalliferous and somewhat decom- 

 posed. A fine view of these falls is given in Volume I, opposite page 

 632. The massive character of these White Mountain gneisses is no- 

 where better shown; and the jointed structure is in a measure brought 

 out in the view. On the west of the road, as we begin to descend the 

 hill going southward, the rock contains andalusite ; and a few beryls have 

 been found in the coarse granite veins that cut this rock. Going south- 

 ward, we find the dark gray gneiss common to this mountain region ; and 

 at the distance of two miles from the falls the dip is N. 23° W. 60°. At 

 the first house in Jackson, — N. M. Cook's, — the gneiss has in several 

 localities an impure limestone interstratified with it. It can be seen east 

 of the road, on a steep hillside about eighty rods south of the house, also 

 in the river at a sharp turn below the house. The rock near the road 

 dips N. 33" W. 45°; and the limestone with gneiss east of the road dips 

 N. 20° W. 85° In the river where the limestone is found the dip is ex- 

 ceedingly variable. At H. Wentworth's the White Mountain gneiss dips 

 N. 38° W. 25°; and on the west side of the road the strata dip N. 65° 

 W. 30°. On Miles brook, at the falls, the rock does not look like the 

 White Mountain rock elsewhere. It contains very little mica; the cleav- 

 age planes are very distinct, and the rock is broken by them so that the 

 water falls over stair-like projections. In the vicinity of J. Rogers's there 

 is an extensive outcrop of granite like that in Albany. The cliff west of 

 Ellis river is made of this rock. The stratified rocks south of Rogers's 

 seem to be more siliceous than the White Mountain rocks generally, 

 VOL. II. 17 



