deserve
fully all the encomiums bestowed upon them in Hitchcock's Report on the
Geology of Massachusetts, and in Shepherd's Report on the Geological
Survey of Connecticut. So abundant and large are the granite rocks in
the eastern part of the United States,* that some single localities
are sufficient to supply many countries with this lucrative article.
Professor Hitchcock divides the granite of Massachusetts into four varieties, viz:
1.
Common granite, which, according to him, embraces nine tenths of
the granite in Massachusetts : the ingredients are a distinct
crystalline structure, of mixed and discriminating colors.
2.
Pseudomorphous granite is that variety in which the mica separates
distinctly the other ingredients, which are closely mixed.
3.
Porphyritic granite : it contains, besides the usual composition of
quartz, felspar, and mica, distinct imbedded crystals of felspar.
4.
Graphic granite : this variety consists of quartz and felspar only ;
the cross-fracture presents the appearance of written characters.
Professor Shepherd divides the ornamental granite of the State of Connecticut into eight different types, viz. :
1. Gray granite.
2.
White granite. This variety I have examined myself in Plymouth,
Connecticut, and so beautiful was its color and close granular texture,
that I took it at a distance for a sandstone, or white marble.
3. Flesh-colored granite.
4. Red granite.
*
Professor Hitchcock remarks that there is nota town in Massachusetts in
which, more or less granite does not occur, eixher as situ or as
boulders.
