138 M. Godon’s mineralogical observations. 
sometimes in powerful veins across the amphiboloid. [Menotomy a, 
Lexington.O]. In this rock, which I found almost always including 
quartz, the felspar exists in large lamina, often interrupted by layers, 
commonly thin, of compact -epidote. Amphibole and quartz are, 
sometimes, in but slight proportion in this rock. 
I unite the above varieties under the specific denomination of 
quartzose. 
16. Epidote enters sometimes into the composition of felsparoid. 
Many specimens present this substance, easy to be known, distribut- 
ed, in equal proportion, with felspar, quartz, and amphibole ; but 
most frequently it is intimately united with felspar, which then assumes 
a more or less intense shade of green, from the usual colour of this 
mineral [Dedham 5, Lynn O]. This species, which, according to 
the basis adopted for this nomenclature, takes the name of 6a 
felsparoid, contains sometimes sulphurated iron. 
17. Mica also appears among the elements of this rock, and com- 
municates to it, in some cases, the aspect and characters ascribed to 
granite. Many instances of this aggregate are to be observed in se¢v- 
eral spots [Brighton 0, Roxbury 0, Dedham 0]. ‘The mica often 
exists in small scales [Newton ©], and frequently it occurs in plates, 
of an inch in diameter, and of a smoaky colour. Sometimes the rock 
seems a mixture of mica and felspar alone. In some cases it includes 
garnet, rarely tourmaline [Dorchester, Roxbury O] ; also oxydulat- 
ed iron. (Magnetic iron ore, Kirwan) [Brighton 0 J. 
This species, which I call granitic, does not form so extensive’ 
masses, as the preceding. It is found contiguous to argilloid [Brigh- 
ton ©] ; alternating with, or rather interposed in the middle of por- 
phyritic wacke [Brighton 0, Roxbury 0]. 
An insulated specimen of granitic felsparoid may be taken for: 
true granite; but geognosists agree in considering this last, which: 
