coos AND ESSEX DISTRICT. 9I 



extend west to Stark water-station. At Stark station we have at the east 

 end of the high bhiff of rock a dark siHceous schist, probably an okler 

 rock than the last ; and this is followed by sienite porphyrite, portions of 

 which are colored by manganese, but elsewhere it is the most beautiful 

 rock for a building stone that we have seen in New Hampshire. Along 

 the river there are no outcrops of rock for two miles ; then we have a 

 rock, apparently an altered sandstone. On Jonathan Pond brook we have 

 a feldspathic quartzite ; but a short distance up the brook we have a 

 quartzite, probably an altered limestone, but the first mentioned rock 

 extends two miles west of Groveton. 



Section X. 



Section X extends from the Maine line, in the southern part of Suc- 

 cess, through Success, Berlin, Kilkenny, Jefferson, and Lancaster, and 

 strikes the Connecticut just north of the mouth of John's river. On the 

 Maine line the height is 1940 feet. The rock is White Mountain gneiss, 

 and here it has an easterly dip, and it extends probably two thirds of the 

 way across Success. It is followed by a hornblende schist, on which it 

 rests. This schist, with beds of granitic rock, extends to Berlin falls, at 

 which place it is cut by numerous trap dykes. Mt. Forist, west of Berlin 

 falls, is a coarse granitic rock, more like an immense veinstone than any- 

 thing else. While at the Falls the rock dips south-east, on the railway 

 below the station the rock is nearly vertical, but we have both easterly 

 and westerly dips. West of Mt. Forist the outcrops of rock are not very 

 numerous. There is a fine-grained, reddish granite east of the Upper 

 Ammonoosuc, and a coarser variety on the hills west. 



In the valley, at the head of the branch of Israel's river that has its 

 rise north-east of Starr King, there are a hornblende gneiss and a fine- 

 grained, dark-colored gneiss. The rock of Starr King is porphyrite, 

 and a similar rock is found on the summits of all the peaks of the Pilot 

 range, except that in some instances the mass of the rock is compact 

 instead of being composed of distinct crystals. In Jefferson, near the 

 Waumbek house, we find a common gneiss. The dip of this rock, not 

 only on the section but elsewhere, is 10° to 20° northerly, and generally 

 10° to 15° west of north. This gneiss extends to Mt. Prospect, just above 

 the road on the east side of the mountain. The rock of Mt. Prospect, 



