13

From this point west the material is mostly covered except for outcrops of a few
beds of comparatively unaltered lava.

21. Two or three hundred yards to the southwest, down a gully, there are nearly
flat-lying outcrops of a dacitic ash of the same character and probably the sam
bed as No. 16. This is in the trough of the fold.

Although the Tranquille beds were not seen in this part of the area,
the Upper Volcanics, consisting of nearly flat-lying basalts, occur.

From Soda Creek to a point above Quesnel, a similar succession can be
observed, namely, disturbed and folded lavas overlain by a sedimentary
series and this, in turn, by flat-lying basalts.

A series of volcanic flows that dip at high angles and are much brec-
ciated in places, outcrops in Fraser canyon just north of Soda Creek,
where they are apparently of great thickness. About 5 miles north of
Soda Creek near the road, are platy olivine basalts striking from north
67 degrees east to north 80 degrees east with dips of 55 to 70 degrees to
the north. Four miles farther up, from a cliff of much brecciated basaltic
rock, large blocks have rolled from the railway cut to the road. Stringers
of epidote and chalcedonic silica cut through the rock which has in places
a pisolitic texture. Farther north on the east side of the road, a volcanic
rock shows columnar structure. Just below the mouth of Australia creek,
on the west bank of Fraser river, isan amygdaloidal basalt, much brecciated
and altered to clay. Beds of clay derived from this basalt are interbedded
with lignitiferous clay or sand at this place. A bed of lignite is said to out-
crop nearby but was covered at the time of our visit and its relation
to the basalt could not be observed. About 14 miles below
Quesnel, on the west bank of Fraser river, there is a series of augite
andesites and other lavas of nearly the same composition, occurring with
white, finely banded, dense, glassy lavas (Figure 12, locality 12). The
rocks are much faulted and brecciated, and altered to clay, while nearby
are beds of arkosic sandstone derived from them and carrying carbonaceous
material. Similar lava beds outcrop on the west bank of the river about
2 miles farther down (Figure 12, locality 14) and in the road west of the
river between these two localities. The very much faulted, brecciated,
and altered condition of these lavas indicates that they are much older
than the much less disturbed, topographically higher, strata of the Fraser
River formation. This conclusion is strengthened by the finding of clay
and carbonaceous beds of undoubtedly later age close to the lava outcrops.

FRASER RIVER FORMATION.

Sediments of Tertiary age were observed along Fraser river from the
Big Bend 8 or 9 miles above Quesnel, to and beyond Australia creek (Figure
1). They outcrop also on the river below and above Prince George. Daw-
son! mentions occurrences on Blackwater river about 30 to 40 miles north-
west of Quesnel and there are probably other occurrences of the same age
near the main Fraser valley. The sediments consist of gravels, sands,
and clays, and beds of lignite and diatomaceous earth.

The gravels of this formation are yellow to brownish and in many
cases well cemented. Their pebbles are well rounded and composed for
the most part of quartz and of metamorphosed sediments and lavas. The
clays are generally grey in colour; some of them are nearly white, and

1Dawson, G. M., Geol. Surv.. Cau., Rept. of Pears 1875-76, pp. 255-256.
5172—2