=lo

fault zone. Upper Triassic and Jurassic sedimentary and volcanic rocks,
cut by a variety of intrusive types, predominate on the northeast side.
All formations trend northwesterly.

Permian

Permian formations comprise not less than 10,000 feet of intere
bedded limestone, quartzite, chert, argillite, slate, greywacke, and
derived schists. The limestone occurs chiefly in northwesterly trending
bands near the Pinchi fault zone, and most of it appears to lie in the
lower part of the Permian section. The bands pinch and swell along
their.strike and at depth, and in places disappear. The maximum single
thickness of limestone is probably 5,000 feet or more. Smaller, ir-
regular bands, as much as 1,000 feet thick, occur at intervals through-
out the Permian section. The normal rock is blue-grey, grey weathering,
medium-grained to dense, and massively bedded. In places the beds grads
from blue-grey to white and cream across widths of from 15 to 20 feet,
Many of the bands are iron stained and carry abundant minute stringers

and specks of red and brown hematite and limonite. Near the Pinchi fenlt

zone some of the grey limestone has been altered to buff weathering
dolomite. ret tt

Associated non=-calcareous strata appear to be much more closely
folded than the limestones and their thicknesses are difficult to es-
timate, but represent a minimum total of at least 5,000 feet. The most
characteristic of these rocks are thinly bedded ribbon cherts, and
argillites. The cherts are generally blue-grey, but vary from cream
grey to black. They consist of beds of chert, ¢ inch to 6 inches thick,
commonly minutely crumpled, separated by partings of black, lustrous,
carbonaceous argillite. In many places the partings have a slaty
Cleavage and have been partly metamorphosed to graphite and mica.»
Other argillaceous members are grey to black carbonaceous rocks, in
beds that are rarely more than 6 inches thick. They are commonly
schistose and in places show a slaty cleavage. Interstratified with
the argillites and cherts are beds of dark grey schistose greywacke and
conglomerate from a few inches to 10 feet thick. Pebbles in the con-

lomerate are predominantly of chert and quartz and rarely exceed

% inch in :diameter. .

Near the junction of Silver and Kenny Creeks lenticular beds
of reddish tuff, up to 50 feet thick, are interbedded with argillaceous
quartzite and limestone.

Bands of greenstone, up to 1,500 feet wide, and lenticular
bodies of greenstone, up to 3 square miles in area, are intercalated
with the Permian sedimentary rocks. They consist mainly of grey-green

to dark green, fine- to medium-grained, chloritioc andesites, amphibolites,
and chlorite schists. In places they cut across adjacent Permian strata;

in other places they appear to be interbedded with them. They probably
comprise flows, tuffs, and minor intrusive rocks. ;

Southeast of the mapearea the limestones carry the diagnostic

‘fossils Neoschwagerina, Cancellina, Parafusulina, Verbeekina, and
Misellina, of Middle Permian ager The following fossil collections \

Geol. Surv., Canada, Paper 42-11, ie: Ge

were made during 1943 and identified by A. B. Wilson of the Geological
Survey:

Collection 1FA, from limestone outcrop at first bend of Nation River be-
low Indata Lake; includes Dielasma n. sp. Age: probably late Carbonif-
erous or Permian.