258 =o. D. Dana—Geology of Vermont and Berkshire. 
hydromica paste, ‘‘abundant in Ira, Middletown, Wells, Poult- 
ney and Pawlet,” and the main constituent of Bird Mountain, 
in Ira—as stated in the Vermont Geological ae (p. 426). 
In Berkshire and farther south. —There are here the same 
slates, but in part coarser. Also (5), a rock of awed aspect, 
in which the mica is a pearly hydrous mica (found in the 
Graylock range, near Williamstown) ; (6) a garnetiferous chioritic 
eran slate, common ; (7) mica es af (8) graphitic mica 
arnetiferous mica schist ; (10) staurolitic mica 
)* 
schist ; (9) g 
schist (in Be liahdry and Sharon 
2. Schists of the Quartzyte group. 
A. In ilpion. —(1) Hydromica Sr which is often very 
fine in grain and is then called novaculite slate ; (2) chloritic 
hydromica eke (8) chlorite slate or ‘ache sometimes contain- 
ing octahedrons of magnetite; (4) hydromica conglomerate, like 
No. 4 above; (5) hydromica quartzyte, all shades occurring 
between hydromica slate and true quartzyte; (9) greenish- era 
hydromica gneiss, containing disseminated chlorite—a kin 
protogine—the mica pearl- -white, the feldspar ices seen by the 
writer on the western slope of the quartzyte and hydromica 
ridge northeast of rise ee the rock much like the kind from 
near Base cabs (No. 5 above). 
B. In Berkshire and farther south.—(1) Hydromica slate, more 
or less chiaits and often garnetiferous ; (2) mica slate, that 
is, fine-grained mica schist; (3) mica schist, varying in color 
from a dark- ray to black, the latter a fissile rock consisting 
largely of black mica; (4) garnetiferous mica schist: (5) quartaytre 
schist. 
Vora of gneiss.—(6) Fine-grained gneiss, thin bedded, the 
mic very small scales aud in general mostly black, the 
Bldeat in small white grains; (7) the same, sae thick-bedded 
and very hard, color moeey light gray, the rock sometimes a 
contorted gneiss; (8) the same, but with little mica, the color 
whitish, graduating ee (9) granulyte, a granular compound of 
quartz and feldspar, with only traces of mica; (10) a whitish 
or grayish striped gneiss having the mica in lines of spots or in 
interrupted lines, looking interruptedly striped, the mica mostly 
biotite; (LL) granitoid gneiss, eh ) fine-grained granite, the 
neiss graduating into these rocks, by a loss of its schistose 
structure; (18) quarizytic gneiss, fine-grained, whitish (often 
yellowish ‘from alteration of pyrite or black mica), a rock t that 
graduates by insensible shades into laminated quartzyte ; (14) 
epidotic gneiss, containing much mica, half of which is musco- 
ace Seger pong tio staurolite as well as garnet in the mica sla te of Salisbury 
ed by Prof. Dewey, in this Journal, vol. viii, P. 7, 1824. Earlier, in 
iia. wits, bs Dabonacmmnsh ial existence of staurolite in She 
