Whitesail Lake Map-Area

quartz-deficient rocks but in southern British Columbia they include such
bodies as the Otter granite in Princeton area (Rice, 1947) and the Coryell
batholith in Nelson area (H. W. Little, personal communication). In central
British Columbia the granitic rocks are most commonly associated with the
Coast Intrusions and though some bodies similar to the less quartzose suite
have been noted, there is no clear separation. In Whitesail Lake map-area
the granitic rocks undoubtedly belong to the Coast Intrusions. Only in one
small group (map-unit 5) is the quartz sufficiently deficient to question its
inclusion with the regular Coast Intrusions. Though this intrusion resembles
the quartz-deficient suite of southern British Columbia, its correlation with
that suite is doubtful. It has, therefore, been included with the regular Coast
Intrusions but is described under a separate heading.

Lithology

Main Mass (8). The plutonic rocks included under map-unit 8
comprise all the granitic rocks in the southwest corner of the area, as well
as related stocks and bosses on Sibola and Chikamin Ranges and in the
region of Morice, Anzac and Tagetochlain Lakes. Also included are two
small cupolas in the Shelford Hills.

These rocks, mainly granodiorite, granite, diorite, and quartz diorite,
are light to dark grey, but may be red or flesh coloured near their contact
with Hazelton group rocks.

In the vicinity of Kitlope Lake, well within the main mass and distant
from any contact, the rock is a light grey, medium- to coarse-grained, fresh
granodiorite. Orthoclase is commonly less than 30 per cent of the total
feldspar and the plagioclase is oligoclase about An, ;. Quartz, which comprises
about 35 per cent of the rock, is clear and occurs as relatively large anhedrons.
Rarely is there quartz-feldspar intergrowth. The ferromagnesian mineral is
commonly biotite, less commonly hornblende. Biotite is present in fine flakes
or well-developed books; hornblende as euhedral crystals or anhedral feathery
masses. Foliation is not common but does occur in the vicinity of faults
and shears.

Southwest of Surel Lake and between there and Seel Lake, the plutonic
rock is a coarse-grained hornblende granite containing large, well-developed
phenocrysts of orthoclase and interstitial greyish white oligoclase and colour-
less quartz. Near Ear Lake the feldspars of this granite are red, due to
contained particles of hematite. The hornblende is a green pleochroic variety.
In thin section the specimens show strain shadows in the quartz anhedrons
and the feldspars are so clouded that identification is difficult. The rock

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