100 
Rex T. Prider. 
of biotites. The scliistosity is interrupted by the idioblastic garnets which, 
during their growth, have pushed the biotite flakes aside. Tlie crystalloblastic 
order is garnet, biotite, plagioclase, and quartz. 
The biotite is a strongly pleochroic variety with X pale yellow, Y = Z 
<.lecp brown, and refractive indices, y = 1-G38 and a = 1*591. Zircon in- 
clusions whth pleochroic haloes are abundant. The plagioclase is an albite 
about AbgAn^ and shows slight normal gradational zoning. The centres of 
some of the crystals are sliglitly turbid wutli sericite-epidote alteration products. 
-r 8 Feet 
o O o 
o o o o 
O O o 
O O 
O O O 
o o 
d 0 - ^ e 
o 5 
O o 
Mica schist 
Quartz-mica schist 
Garnet-mica schist 
Cummingtonite schist 
Garnet-mica schist with 
cummingtonite hands (§” -wide) 
Mica Schist 
Fig. 8. 
Sketch section of small w^aterfall at the head of Gorge Creek 
(15 chains S., 122 chains W., from datum), showdng the relation 
of cummingtonite schists to the mica schists. 
From the same outcrop as tlie garnet schist comes : — 
(c) Gedrite-cummingtonite-plagioclase schist . — A typical specimen (19947) 
is a pale greenish-grey, fine grained bandcnl rock- — light greyisli to white' bands 
to J in. tliick alternating witli gr('enish-grey bands up to \ in. tliick. Under 
tlie microscope there is a well-marked schistose structure and the minerals noteil 
w'orc gedrite, cummingtonite, plagioclase, and c[uartz. 
The amplhboles occur in well-shaped prisms (often w'itli ])oikiloblastie 
inclusions of plagioclase) uj) to 1 • 5 mm. in length. Tliey all he witli their 
longer axes in the plane of scliistosity, but appear to be of random arrangement 
in these planes since basal and longitudinal sections are present in aj^proxi- 
matciy eipial numbers in all sections cut at right angles to the scliistosity. 
Both are jiale clove-brown, not noticeably pleochroic varieties and are dis- 
