67
CLAY LOCALITIES EXAMINED.
REFRACTORY AND SEMI-REFRACTORY CLAYS.

Clays of this type were examined at Chimney Creek bridge (Figure 2,
locality 15), at Baker Creek canyon opposite Quesnel (Figure 1, localities
7 and 8), at a point 8 miles north of Quesnel (Figure 1, locality 6), and at
another place 30 miles above Prince George (Figure 1, locality 2). All
these localities lie close to the west bank of Fraser river.

Chimney Creek Bridge.

Samples 1 to 4 were taken from a point 1,400 feet in elevation above
Chimney Creek bridge, west of Fraser river and within sight of the bridge
(Figure 2, locality 15). The bridge is about 26 miles by road from 150
Mile House and 15 to 16 miles over a high grade from the railway at
Williams lake. The clays occur as residual masses produced by the altera-
tion of a series of Cache Creek fine-grained quartzites and argillites. The
clay-bearing zone is much crumpled and faulted, whereas the undisturbed
beds below and to the side are hard, fresh, and free from clay. Figure 11
shows the mode of occurrence. Over the clay there are silts and basalts
of Tertiary age.

A section from the top down is as follows (Figure 11).

Thickness
in feet.
(a) Black basalt nearly flat-lying and forming the summit of the slope. -
The lower 15 feet is broken up and consists of broken basalt
fragments mixed With: Clay eet... oo oe ee et ee oe 40
(b) Fine silt, unconsolidated and well-bedded, probably of Tertiary age 10
(c) Fine-grained argillite or quartzite, yellowish white, partly altered to

GIB ko Seioe te mea te ee AE PT Oe ee aa ke ee 30
(d) Bluish, fine-grained quartzite, the bed much crumpled and appar-
ently wholly changed to clay, although the sample carried 50
er cent of non-slaking material. Sample tested............ 2 to 4
(e) Silty argillite or quartzite changed to yellowish white clay, 15 to 20
er cent of fresh rock present. Sample tested..... Dials see 25
(f} Sear: of white clay with pinkish streaks, showing in places only,
in a much crumpled and faulted bed. This is the best clay in
thie bank. -oampie tested: <3. 2 2 ee ee ae os 2 to 3
(g) Resembles (e) with seams of white clay through it, percentage of fresh
rock about the same as in (e). Sample tested...... Ses 25

(h) Alternate bands of silty argillite or quartzite varying slightly in
texture and colour, largely altered to clay but with more fresh
Tock present than in: (d); Ce), (), (@). 22 oe ee ee 85

(j) Black, carbonaceous argillite somewhat altered to clay

(k) Alternations of argillite and quartzite exposed for 800 feet down
the slope. These beds are not changed to clay.

The beds from (k) downward strike along the slope and are practically
undisturbed; those from (c) to (g) are very much crumpled, twisted, and
appear in all attitudes, and the bed from (h) is less disturbed. The altera-
tion to clay of beds (c) to (g) is very pronounced; (h) is partly altered to
clay and from (k) down the beds are quite fresh. Beds (c) to (k) belong
to the Lower Cache Creek series.

Samples 1, 2, 3, and 4 correspond to beds (d), (e), (f), (g), in the above
section.