406 JOSEPH H. PERRY 



SiOz - 70.18 



AI2O3 15.13 



Fe203 ------ 00.68 



FeO - - 1.54 



MnO - - - - - - 0.13 



CaO ------- 0.84 



NajO ------ 2.67 



K2O ------- 8.93 



Loss at I io"C. - - - - - o.io 



Loss over blast ----- 0.22 



100.42 

 The disintegration of the rock is both chemical and mechan- 

 ical. The triclinic feldspar and the mica are the first minerals 

 to decay. The frost and mechanical agents then act between 

 the minerals and along the planes of cleavage in the orthoclase, 

 prying apart the minerals and crumbling the rock. The coarse- 

 ness of the texture probably materially aids these agents in their 

 work. The comparatively rapid disintegration of this granite 

 does not specially recommend it as a building stone, though the 

 somewhat numerous quarries in it indicate a considerable use of 

 it for that purpose. 



Within the Conway granite are found inclusions of an earlier 

 granite. The rock of these inclusions is of a light gray color, of 

 a medium-fine, granular texture, and is perfectly massive, with- 

 out banding, foliation, or parallel arrangement of the minerals. 

 The feldspar is white and glassy, and is partly triclinic. 

 The quartz is finely granular and slightly smoky, and forms with 

 the feldspar an intimate mixture. The black biotite is so abun- 

 dant as to give a gray color to the whole rock. 



Generally, on the different sides of Kearsarge, as well as on 

 the sides of Bartlett, there is found above the Conway granite a 

 granite-porphyry. In this the feldspar phenocrysts measure 

 about one-fourth inch through. These feldspars are orthoclase, 

 and are in part reddish throughout, and in part reddish on the 

 borders with a white center. The outline of the phenocrysts is 

 generally rounded rather than angular. The quartz, of a smoky 

 color, occurs in part in distinct particles, one-sixteenth to one- 

 eighth inch through, sometimes showing crystal forms. The 



