366 J. D. Dana on the Quartzite, Limestone, ete., 
so-called Canaanite ; it also occurs in the next town, Sheffield, 
but is sparingly met with in the limestone farther north. 
Brown mica in scales is also common in the less pure layers of 
the Canaan limestone. 
B. Metamorphie schistose rocks and slates.—The following are 
among the occurring kinds of schistose and slaty rocks. 
(1) Mica schist, abounding in mica, the scales largish, their 
colors white and black intermingled, the latter predominating. 
(2) Arenaceous mica schist, with minute scales of mica. 
(3) Mica slate, using this term in a sense distinct from that of 
mica schist, for a shining slaty rock, smooth in surface, inter- 
mediate between mica schist and clay slate, and also between 
* Trepeat here that the hydro-miea slate was formerly called talcose slate, and 
. by Emmons 7 b i i 
(Vt. G. Rep., p. 708) to contain no magnesia. 
The following are analyses; 1 by Hunt; 2 to 4 by Barker: 
Si 6 COs Mg (Ce 6Ne. K | vol. 
1. Ste Marie, Canada, red, 66°70 16°20 6-90 2°65 0°67 [3°78]  3°10=100 
, 1810 12-80 1:23 5°57 089 0-60= — 
: > y 90 20°00 f 03 
4. Pownal, Vt, bh-gray, 42:90 42:20 1:98 0-78 1-33 5-24 5°60==1000 
These analyses indicate that it is often impossible to distinguish the hydro-mic® 
paged guish the 2y' 
slates; for No, 2, although described in the Vermont Report as “the most unc 
