Limestone outcrops on the east side of the Columbia River (Upper Arrow Lake) near the mouth of Wallace Creek, just northeast of Sidmouth.

A bed of limestone of the Lower Cambrian Lardeau Group, at least 30 metres thick, is exposed for 400 metres along the steep mountain side. The limestone and overlying dark green amphibolite schist of the Juwett Formation strike 170 degrees and dip 35 to 50 degrees east. A well developed set of joints strike 040 degrees and dip 80 degrees northwest, while a second set strike 120 degrees and dip 80 degrees northeast.

The bed contains fine to coarse grained, mostly white limestone with some sporadic bluish grey banding and brownish streaks developed parallel to the stratification. A 1.2-metre thick band of yellowish magnesian limestone is developed near the centre of the bed. The rest of the rock is high in calcium composition. Two chip samples analysed as follows (in per cent):

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Sample A Sample B

CaO 55.06 54.52

MgO 0.24 0.99

SiO2 - 0.36

Insol. 0.65 -

Al2O3 0.24

R2O3 0.25 -

Fe2O3 0.15 0.12

MnO 0.02 -

P2O5 0.02 -

Sulphur 0.070 trace

Ig. Loss 43.62 -

Water 0.01 -

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Sample A is comprised of chips taken at 1.52 metre intervals across an 18.3 metre wide quarry face (Property File - J.W. McCammon, 1968). Sample B was taken across the full width of the limestone bed, excluding the magnesian limestone band (CANMET Report 811, p. 207, Sample 78).

An unsuccessful attempt was made to quarry the limestone for stucco chips sometime between 1944 and 1968, no production figures are available.