410 JOSEPH H. PERRY 



little finer in texture than the granite farther down the stream. 

 Ascending the brook bed a few feet, the rock begins to be 

 slightly porphyritic, and at the same time contains less biotite. 

 There may be distinguished in this phase the beginning of a 

 finer-grained groundmass. Then 150 feet up the brook bed, 

 only 20 feet or so higher vertically, the surface of the ledge 

 being exposed all the way, may be found the granite-porphyry. 

 Its resemblance to the preceding is very close, yet the fine 

 groundmass of a light gray color is clearly defined, inclosing 

 the distinct feldspars, one-half to three-fourths inch through, 

 and the blebs of smoky quartz, together with the black foliated 

 masses, one-eighth inch or less through, of biotite. The biotite 

 is noticeably less in quantity than in the granite beneath. 



This gradual variation and gradation may be easily traced 

 until, at the 1,100 foot level, the rock is a quartz-porphyry, the 

 biotite appearing not at all, or now and then only in traces, and 

 the rock, aside from this, identical with the quartz-porphyry 

 higher in the mountain. 



The quartz-porphyry of these mountains has thus far been 

 spoken of as if it were a simple and pure porphyry. While the 

 prevailing rock in the upper part of the mountain is the porphyry, 

 this always contains irregular, angular fragments of other rocks, 

 so that it is difficult to obtain a hand specimen that does not 

 show one or more of these inclosed fragments. In places the 

 rock fragments are so abundant as to make up the larger part of 

 the ledge, constituting a breccia with the porphyry as the 

 cement. Such a breccia may be seen on the south slope of 

 Kearsarge at the 2,000 foot level, and continues to appear up to 

 the 2,150 foot level. The fragments constituting the breccia 

 vary in size from a fraction of an inch up to two feet or more in 

 diameter. Those most frequently seen are of phyllite. 



There is a large mass of this phyllite in the southern slope of 

 Mount Kearsarge, which is crossed by the mountain trail at the 

 1,425 foot level. From this trail the phyllite area may be 

 traced easterly and southeasterly to the first brook on the 

 mountain side. The phyllite constitutes a mass in the south 

 side of the mountain about one-fourth mile in length and 100 

 feet thick. 



