J. D. Dana on the Quartzite, Limestone, ete. 257 
analysis in this case. 
Per.cent".." ssa2 
Th 
= 65°42 eory =34'58 
Vil. 
Wt. of copper taken="6153 grms. Wt. of lead taken=‘3252 grms. Total “9405 
. fo found == "6126. 4 fognd==*8027 2 
==6513 
Per cent ‘“ us 
Theory 
Arr, XXVIIL—On the Quartzite, Limestone and associated 
rocks of the vicinity of Great Barrington, Berkshire Co., Mass. ; 
by James D. DANA. 
[Continued from page 91, vol. v.] * 
8. From the Housatonic Valley eastward. 
THE region about to be described is within the same half a 
dozen square miles of area that have afforded the facts men- 
i ir. It lies to the 
south and southeast of Monument Mountain, and is within 
st 
or gneiss, and limestone beyond what has been elsewhere 
observed, 
2 So 
op 
# ee: a 
Section across Housatonic Valley and Monument Mountain. 
mica schist), dipping 20° to 25° to the southeastward, as_repre- 
sented in the annexed section (fig. 8). At the east end garded 
No change to a westward dip, so as to make the whole a gentle 
450, ne Preceding parts of this Memoir are in vol. iv of this Journal, pp. 362, 
50, and vol. v, pp. 47, 84. 
t See this Journal, III, iv, 450. 
Am. Jour. Scr.—Tatrp am Vor. VI, No. 34—Oct., 1873. 
1 
