48 STRATIGRAPIIICAL GEOLOGY. 



artstown it can be seen half a mile east of Alden Fletcher's. In 

 Clarksville it outcrops a mile west of J. Gethercole's. In Pittsburg it 

 forms a prominent ridge on the east of the rock, where it leaves the 

 Connecticut river and turns northward. From this point to Connecticut 

 lake the outcrops are frequent, also along the road north of the lake, and 

 it forms the high hill west of Round pond. Going north there are nu- 

 merous outcrops along the old "tote "-road to Third lake, and north of 

 this lake it is the principal rock of one of the high points on the bound- 

 ary. It is a dark gray rock, often has a greenish tinge, and, in some 

 specimens, the hornblende is quite distinct. It is extremely hard, as 

 every one who has attempted to work it will testify. In some localities 

 it decomposes by the action of the atmosphere, probably on account of 

 the presence of lime, for in some places it contains a sufficient amount 

 of lime to effervesce when acid is aijplied. In no part of New Hamp- 

 shire is there better pasturage than where this is the prevailing rock; 

 but frequently, on account of the great number of boulders, the land is 

 not desirable for tillage. The following analysis by Prof. Seely, though 

 probably imperfect, shows the chief constituents of this rock: 



Silica, 49-51 



Protoxide of iron, 21.42 



Alumina, 14.88 



Lime, 8.52 



Magnesia, 4.86 



99.19 

 This rock forms nearly all the boulders of Pittsburg east of its outcrop, 

 and they have been carried far to the south-east, one having been seen 

 east of the Magalloway. It contains very few veins, and those seen were 

 of vitreous quartz. 



The green schist does not seem to be continuous, but where it does 

 not outcrop it may be concealed by drift. It is a prominent rock in the 

 south part of Columbia, just east of a starch mill on Sims stream. In 

 Colebrook it outcrops on the road west of Young's mill, then on the road 

 near C. I". Hardy's. In Pittsburg it is a common rock, and it comes in 

 contact with the argillaceous schist on the road along the Connecticut, 

 just before the road turns north. It is the rock of the east end of Con- 

 necticut lake, and it can be seen on the two small islands of that lake, as 



