132 STRATIGRAnilCAL GEOLOGY. 



in the Merrimack district; lastly, inconsiderable areas in Albany and 

 Bartlett. 



A trip up Mt. Hope and the mountain opposite Nancy's brook in 

 Hart's Location affords us a few observations concerning some of the 

 rocks of the first-named area. Starting from the Saco river by the old 

 Davis path, the common granite of the Notch is seen half-way up Mt. 

 Hope. This is followed by a porphyritic rock (No. 430). Mt. Hope is 

 a small eminence at the head of Glen Crawford, just south of Mt. Craw- 

 ford. The Glen is shown in the hcliotype of Mt. Crawford from Bemis. 

 Mt. Hope and the southern part of Mt. Crawford are composed of fine- 

 grained compact feldspathic mica schists, dipping 60° N. 3° W. This 

 area is marked like Mt. Webster by the occurrence of enormous granite 

 veins, with the direction N. 8° W., and some of them are at least thirty 

 feet wide. These veins are supposed to have been connected with the 

 eruption of the Conway granite. Some of the specimens from Mt. Hope 

 are micaceous quartzites. On the south side of this eminence the gran- 

 itic gneisses predominate, with only an occasional layer of the quartzite. 

 Passing to the next mountain south, the schists dip 75° N. 52° E., also 

 N. 23° W. Occasional masses of granite show themselves. On the very 

 highest point of this mountain, and opposite to the mouth of Nancy's 

 brook, the rock is like the common Mt. Washington schist, with a few 

 spangles of fine mica among the abundant larger pieces. The specimen 

 has a reddish color, from ferruginous stains. The dip is 70° N. ^8° W. 

 In passing down to Nancy's brook, rocks similar to those on the summit 

 show themselves, with essentially the same position. Half-way down 

 there is much of a hard, jointed granite. At the western base of the 

 mountain the rock agrees with that on its highest part. 



The rocks are well exposed on Nancy's brook. At its mouth the 

 railroad passes through a large cutting, and the fragments thrown out 

 may be taken as typical of an important variety of this formation. The 

 color is mostly dark, nearly black, with a whitish sprinkling of feldspar 

 or quartz. The substance is largely a compact silica, but the mica is 

 well developed, and is not quite so conspicuous as the blotches on the 

 presidential summits. The mica is often distributed in impalpable shin- 

 ing streaks instead of scales. At the saw-mill the dip is 45° N. 87° 

 W. The brook has excavated a flume through the ledge, and the rock 



