SP ne eee aye el 
- 
J. D. Dana—Taconie Rocks and Stratigraphy. 489 
1. Tuer Scuist WITH THE QUARTZYTE. 
The schist of the region varies from very fine-grained thin- 
fissile glossy hydromica (or sericite) schist to coarsish mica 
schist containing garnets and staurolites; and toward the east, 
to arenaceous or quartzytic mica schist without staurolite, and 
mostly without garnets. Each of the rocks contains dissem- 
inated magnetite, and often pyrite, and sometimes these min- 
erals are in distinct crystals. inute brown or brownish 
tourmalines also are found sparingly in all the kinds. 
e term quarizose or quarizytic is used beyond synony- 
mously with arenaceous, it referring to the occurrence of quartz 
grains in the schist and not to vein quartz. In the hydromica 
and mica schist the grains lie in small, thin or thick, interrupted 
layers between the leaves of the schist, as if deposited like the 
interrupted laminations of sand in some river-valley clays; 
they vary in length from an inch to many feet, and in thick- 
ness from >4,th of an inch and less, to 4 inch or more; they 
are smallest in the finest of the slate. 
The facts mentioned below are from both macroscopic and 
microscopic examinations. 
A. Section through the Southern part of Mt. Washington from 
Winchell Mountain to Canaan Mountain. 
_ 1. Mt. Winchell—At the summit of Mtg Winchell the rock 
18 thin-fissile hydromica (or sericite) schist. It consists chiefly 
of muscovite mica in minute scales about yz}, to zh, inch 
tions, as _ se transverse section. Minute tourmalines 
rather rare. Chlorite not observed either macroscopically o 
In the thin slices. A eastern foot of Winchell the 
tock is the same, but slightly coarser and often a little crum- 
pled (from pressure). Muscovite scales are mostly 74, to 
Inch across; some biotite scales occur 34, to z4, inch across 
and generally grouped. 
2. West side of Mt. Washington—North of Millerton—about 
amile east of the base of Winchell mountain—the rock isa 
Very fine-grained mica schist, consisting chiefly of muscovite, 
With little chlorite; muscovite scales mostly zy to y}q inch; 
the biotite scales larger. Quartz grains in thin interlamination 
often making up a fourth or more of the thickness. Garnets 
are few and small, or absent; orthoclase feldspar is found in 
Occasional grains; staurolites are absent. 28 
3. Hast side of Mt. Washington, in Salisbury.—The schist is a 
coarsish muscovite mica schist with some biotite and usually 
no chlorite; muscovite scales about zt, to zy inch, and biotite 
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