of the valley-fill. In the main valleys of Lightning and Slough Creeks, however, the
present creeks have not yet cut down to bedrock and are flowing on top of a consider-
able thickness of drift. On the lateral tributaries, depending upon the thickness of
the drift and upon the longitudinal profile of the creeks, the creeks may be flowing on
bedrock along part of their course and upon a variable thickness of drift along the
remainder. Postglacial streams, through the erosion of glacial material in which some
gold-bearing gravel has been incorporated or through the erosion and concentration
of gold-bearing gravel in earlier-formed stream deposits, have concentrated gold on
bedrock and in shallow surface gravels lying on glacial drift.

The gold-bearing gravel lying on bedrock below the level of Lightning Creek has
been mined from LaFontaine shaft, below the mouth of Anderson Creek, up-stream to
the foot of the canyon below the junction of Houseman Creek (see accompanying map,
also Fig. 1). The depth of bedrock below creek-level is indicated by the depths of the
various working shafts: LaFontaine, 165 feet; Costello, 100 feet; Vulcan, 90 feet;
lower Victoria, 72 feet; upper Van Winkle, 60 feet; and Ross, 36 feet. The deep
channel of Lightning Creek extends eastward from the Edinburgh tunnel, but in that
section was not profitable and has not been mined. Lightning Creek itself swings
north-eastward and flows on bedrock in a canyon below the mouth of Houseman Creek.
Shallow gravel was mined in the creek in the canyon section.

Bedrock benches along the sides of Lightning Creek, representing one or more of
the earliest levels of the creek, were mined on the south side of the creek, extending
down-stream from Last Chance Creek past Ah Quay Creek, on the south side between
Grub Gulch and Van Winkle Creek, on Nason Point, Kelly Point, Butcher Bench, on
benches on the north side of the creek up-stream from the mouth of Amador Creek,
and at Dunbar Flat.

The lower stretches of certain tributaries, such as Anderson, Davis, Last Chance,
Chisholm, and Perkins Creeks, are graded to the deep bed-rock level of Lightning
Creek. Consequently, drifting ground lying below creek-level and worked from shafts
existed at their mouths and for some distance up-stream. Others, such as Grub Gulch,
Van Winkle, Amador, and Houseman Creeks, were graded initially to a level of Light-
ning Creek higher than the present. Upon rejuvenation of Lightning Creek these
tributaries did not maintain a profile graded to the deep level of Lightning Creek, and
at short distances back from their mouths bedrock in these creeks is at or above the
present level of Lightning Creek. Consequently, bedrock gravel near the mouths of
these creeks was found that could be worked by hydraulicking or drifting from adits.

Deeply buried gravel at the mouth of Anderson Creek was prospected or mined
from a shaft near the mouth of the creek. Up-stream, gravels were washed fairly
extensively as far as the top of the Trelease workings near the south-west corner of
Lot 11404, beyond which scattered shallow workings extend almost to the intake of the
Jones ditch leading to Donovan Creek. Shallow gravel is being worked on the west
branch of Anderson Creek by Emil Falck.

Deeply buried bedrock gravel at the mouth of Davis Creek was mined from an old
low-level drift. Up-stream, as the bedrock of the creek rose above Lightning Creek,
bedrock gravel beneath 25 feet and more of boulder-clay was hydraulicked. The top
end of the worked section of Davis Creek is on the east branch 400 feet north-east of
the north-west corner of Lot 1670.

A hydraulic pit extending about 1,300 feet south on Ah Quay Creek was worked
to bedrock that rises above a bedrock bench extending along the south side of Lightning
Creek.

Most of the deeply buried gravel at the mouth of Last Chance Creek was mined
from shafts. A small remnant of unworked ground, possibly a bench flanking the
channel, was found recently by Alf Brown, of Stanley, through drilling. He has sunk
a shaft about 500 feet south of Lightning Creek, from which he proposes to drift the
bedrock gravel. The lower section of Last Chance Creek, including a section pre-

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