Pirsson and Washington — Geology of New Hampshire. 345 



zone of the igneous rock mass. On the south the drainage is 

 less clearly defined and is carried off through a series of small 

 lakes which empty to the southward. On the other sides 

 small brooks run into the lake. The mountains are quite gen- 

 erally covered with trees and.brushwood on the steeper slopes; 

 below these are generally open pasture fields, and the highest 

 crests and summits are more or less bare rock exposures with 

 small meadows between them. At the foot of the eastern and 

 northern slopes, along the shore of Lake Tv~innepesaukee, runs 

 the Lake Shore Railroad, a branch of the Boston and Maine 

 Railway system, which ends at Lakeport-Laconia. These 

 towns with Alton Bay at the south end of the lake and the vil- 

 lage of Gilford are the most important places in the vicinity 

 of the mountains, although the shore of the lake at their foot 

 is thickly clotted with summer cottages and places of resort. 

 Around them elsewhere is an open farming country and the 

 high valley between the northern extension and the eastward 

 one of Mount Straightback is also a cultivated area reached 

 by a road over the mountains from Gilford to West Alton. 



Historical. — The only reference in the literature to the 

 geology of the Belknap Mountains which we have been able 

 to find is the short description by Hitchcock.* He states that 

 the mountains are composed of eruptive syenite similar to that 

 of Red Hill in Moultonborough. He describes briefly a few 

 localities, and mentions that in places it is in contact with 

 porphyritic gneiss and mica schist. He thinks that the syenite 

 has come up through a synclinal fault. Near the contact with the 

 porphyritic gneiss it is brecciatecl and full of dark hornblendic 

 spots. He alludes to a " trap " dike ten feet wide cutting the 

 syenite in one place, and says that reddish f eld spathic veins are 

 common. This is an evident reference to one of the lampro- 

 phyric dikes and the felsitic ones. He also refers to a breccia 

 which is found in one locality, the coarser syenites occurring 

 as nodules in a rock resembling trap. The mass of diorite 

 (camptonose) rock above the Gilford station on the lower west 

 slope of Locke's Hill is not mentioned and was probably not 

 seen by him. In Hawes'f report the rocks of this area are not 

 mentioned, although he describes the syenite of Red Hill. 



Geology of the Belknap Mountains. 



The Belknap Mountains are formed of a mass of granitic 

 igneous rock, the result of the upthrust of a great body of 

 molten magma into the rock masses surrounding it, the latter 

 being broken and displaced to permit of its entry. In sequence 

 to this major event there were later upthrusts of other magmas 



* Geology of New Hampshire, vol. ii, p. 607, 1877. 

 f Lithology of New Hampshire, loc. cit., vol. iii. 



