AMERICAN 
JOURNAL OF SCIENCE AND ARTS. 
[THIRD SERIES.] 
e. 
Art. XXXIV.—On the relations of the Geology of Vermont to that 
of Berkshire; by JAMES D. Dana. 
[Continued from page 207.] 
2. LITHOLOGICAL CONCLUSIONS: WITH SPECIAL REFERENCE TO 
Ui OF LITHOLOGICAL CHARACTERS AS A TEST O. 
GEOLOGICAL AGE. : 
subject. 
The Taconic slate-belt in the western half of the limestone 
area and the quartzyte group of the eastern half may be sep- 
arately considered, and, afterward, the relations of the two. 
1. Taconic slate-belt or range. 
The diversity of rocks in the Taconic slate-belt is small 
compared with that in the Eastern or Quartzyte group. 
A. In Vermont.—The rocks, as has been explained, are (1) 
argillyte to the north; then argillyte along the center with 
borders of (2) hydromica slate varying from a pure slaty hydrous 
mica to a mixture of hydrous mica with more or less quartz; 
(3) chloritie hydromica ‘slate, in which quartz seams and veins 
(often chloritic) are common. Besides these, there is (4) a 
hydromuaceous conglomerate, consisting of quartz pebbles in a 
Am. Jour. — — Vor. XIV, No. 82.—Ocrt., 1877. — 
