Geology and Mineralogy of a part of Massachusetts, &c. 59 
specimens, the quantity of serpentine is very small, and 
the colour yellowish sf pe In other specimens the ser- 
pentine is distinctly to be seen. The mineral efferyesces 
with acids, and the seygalinn structure of the eget or 
of the magnesian limestone, is obvious. I have supposed 
ita magnesite ; but its characters would place it ae the 
general description of Vert Antique. 
Cummingtonite. 
I have given this name to a mineral found by Dr. J. Por- 
ter in Cummington. It appears to be a variety of epidote. 
Its colour is gray, sometimes with a faint reddish tinge, un- 
less when acted on by the weather, when its colour is yel- 
Jowish. It is in indistinct prisms, with oblique seams like 
zoisite, and in radiated or fascicled masses, which are com- 
posed of slender og Lustre somewhat shining or 
pearly. It is nearly as hard as quartz, and sometimes 
makes a slight i famprceeiath upon rock crystal. Before the 
blowpipe it blackens, and a small portion melts, when the 
heat is very great, into a black slag, which is attracted by 
the magnet. Its point of fusion seems to be about the same 
as that of see. After allowing for some absorption, the 
sp. gr. may be taken as about 3.42. It is so peculiar a 
mineral, that it deserves, even as a varicty, a particular 
name 
With quartz — garnet, it forms a large mass in Cum- 
mington. The cavities in the rock contain pulverulent 
sulphur of a ainy: greenish colour; and minute crystals of 
Magnetic oxide of iron are also Touts 3 in it. 
Yenite. 
_ This mineral is found at a Con. Itis foliated i in 
which ] te seen from Europe. It is dark green, opaque, 
lack globule. 
From a partial analysis, it seems to nave the composition 
of t he pe pean yenite, and the silex and iron are nearly 
in the peoportsts given by analysis. Sp. gr. 3.83. When 
melted, the globule is like that of the European yenite, at- 
iracted by the magnet. It is also in the form of flattene 
