604 STRATIGRAPIIICAL GEOLOGY, 



these areas resemble each otlicr at all, and each one constitutes a moun- 

 tain mass. 



Ossipec group. We find this is an elliptical mass, nearly round, a little 

 more than half composed of porphyry, with a narrow belt of Albany gran- 

 ite on the west side, a considerable tract of Conway granite in the east, 

 and the Pequawket breccia on the north-east. The porphyry is better 

 developed here than anywhere else in the state. It is partly brecciated 

 and partly stratified, like a clay slate without very many cleavage planes. 

 An excellent place to see this rock is near the hamlet east of South Tam- 

 worth, half a mile up the mountain's side, where some have fancied there 

 might be cord. The rock is a fine, compact fibrolite, with occasional 

 black scams resembling bony coal, dipping 15° S. 20° W., or into the 

 mountain. Drift conceals most of the ledges at the north base of the 

 mountain, but the slaty band crops out a mile west of the "coal"-opcning, 

 at the end of a spur. On following up the valley south from the village 

 of South Tamworth we find slates, felsites, and breccias at Thompson's 

 shingle-mill, mostly dipping west. Epidotic seams and bunches are plen- 

 tiful. Above N. Johnson's, compact, dark felsites have vertical seams, 

 with a north-east strike. The mountain south has not been visited. At 

 Ossipee falls, on the south side of the mountain, is a fine display of these 

 black and spotted porphyries. The joints at the top of the falls dip south- 

 east, in a reddish rock. The lowest slate seen is black with greenish 

 spots, inclined 25° N. W. The ridge south of Canaan is a coarse gray 

 fclsite. North of Dan Hole pond a steep hill is comjiosed of a black, 

 spotted felsite, with joints dipping 60° N. 25° W. We also find felsite a 

 mile south of l^ear Camp river, just in the edge of Ossipee, in the valley 

 north of Mt. Whittier. The peak east of Mt. Whittier shows brecciated 

 porphyry, while the principal mass is a spotted granite containing slaty 

 fragments, thus resembling the Pequawket rock. Jointed seams run 

 N. 40° W., dipping N. 50° E. The smaller eminence just against West 

 Ossipee station is composed of breccia, some pieces of slate being two 

 feet long. Some ledges consist of a jumble of masses of the dark por- 

 phyry, almost too large to be styled a breccia. Above the "coal mine" is 

 a breccia, where the pieces are of small size, and the cementing material, 

 almost like trap, constitutes the principal portion of the rock. It com- 

 mences perhaps one hundred and fifty feet above the mine, and is believed 



