11

Pegmatite and aplite dykes were seen at the muscovite occurrence
north of Canim lake; on Timothy mountain; and on the silver-lead claims
on Willow river.

CRETACEOUS.

The Cretaceous as mapped by Dawson lies in a narrow strip trending
north-northwest and following the Fraser from below Lytton to Fountain
ereek. No rocks were recognized in the course of this work as Cretaceous
to the north of Fountain creek afd no mineral deposits were examined
in the Cretaceous. Between Lillooet and Fountain creek the Cretaceous
is described by Dawson as consisting of highly indurated sandstones,
argillites, and conglomerates. Specimens taken from cuts in the railway
21 miles north of Lillooet, on the Big Bend of the Fraser above Bridge
Creek mouth, and at Fountain creek, were banded, very dense, rhyolitic
glassy tuffs; others resembling sandstones proved to be crystal tuffs of
dacitie composition and may correspond to those described by Dawson as
arkosic sandstones. The Cretaceous of Fountain ridge lies in a syncline
bounded by faults and trending about north 25 degrees west.

COLDWATER GROUP.

The Coldwater group was examined in three places, in and south of
the landslide at Pavilion station, and near Clinton. A sample of clay |
derived from the Coldwater at Pavilion was tested in the laboratory but
is not of commercial value. Dawson found traces of gold in certain samples
of conglomerate from this group and advised prospecting for gold in them.
Near Pavilion the outcrops seen consisted of a conglomerate with boulders
of Cache Creek rocks and granites, ‘held in a grey matrix that weathers to a
sticky red clay; with the conglomerates are thin, buff-coloured shales or
tuffs. Dawson states that the main part of this area is occupied by slightly
calcareous, arkosic sandstones. The weathering of the clay on the south
side of the valley caused an immense landslide. Although the upper part
is still moving this slide started at least one hundred and perhaps many
hundred years ago. It is fan shaped and hummocky at the base, and its
papesraphy and composition resemble that of a glacial moraine (Plate

ITA).

Dawson mapped as Coldwater a small area near the epsomite lake at
Clinton (Figure 8, localities 10 and 11). An outcrop of conglomerates,
sandstones, and grey-green shale with plant remains occurs in the hill west
of the lake (Figure 8, locality 11). The conglomerates carry pebbles of
Cache Creek quartzites of uncertain age. Conglomerates occurring on
the road directly south of the lake,and elsewhere near Clinton, are apparently
of later age.

LOWER LAVAS.

Later than the Coldwater are great accumulations of lava placed by
Dawson in the Miocene. He divided them into two portions separated by
a period of sedimentation during which certain fine-grained tuffaceous
oe were deposited. The intermediate sediments are called the Tranquille

eds.