MEMBERS OF THE PYROCRYSTALLINE CLASS. 05 
blocks, of a flesh red, occur at Granville. Another coarse 
granite is found in Williamsburgh, Mass., in which the mica is 
plumose. These coarser granites are frequently porphyritic, 
and the feldspar is the most prominent mineral; but these 
varieties pass into the finer kinds, and also into gneiss, and 
might be designated by the descriptive name, granitic gneiss. 
This variety is well exhibited in the rocks of St. Lawrence 
county, N. Y., where the granitic rocks are more frequently of 
a character which places them in intermediate positions. The 
fine granites of New England, fine in texture, have long been 
known at Quincy, Chelmsford, Fitchburg, and Sharon. In Maine 
the granites are both fine in texture and fine in quality. They 
form the caps of hills, and the mass not being remarkably thick, 
it has frequently been removed, exposing the gneiss or mica 
slate upon which it rested, and also bringing to view the dykes 
through which the molten matter had reached the surface. It is 
probable that these masses, capping the hills, have been greatly 
reduced in thickness by denudation. Some of the granites are 
fine, and have a red color of a uniform tint; others are gray, 
with a greenish tinge; and others still dark green, from the 
presence of both mica and hornblende. Tt is unnecessary, how¬ 
ever, to attempt to describe all the varieties of granites of this 
country. Some of the best, for building stone, belong to 
the gray fine-grained kinds, which flowed through narrow 
fissures in mica slate or gneiss, and which appear to have over¬ 
spread large areas, as those beds in the neighborhood of Augusta 
and Hallo well, in Maine; while those w r hich are coarse occur 
in veins in gneiss or mica slate. These usually furnish feldspar 
in larger blocks, free from iron, and it is often suitable for the 
manufacture of porcelain. The granites whose mica is in large 
folia, are unsuitable for building, or works of construction. The 
granites of the Rocky Mountain range resemble the common 
gray and flesh colored granites of New England. 
§ 53. Jige of granite. Granite, as it is described in the 
foregoing paragraphs, may or may not be connected with the 
oldest masses of the globe. Its age and position is indetermin- 
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