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CHAPTER II

GENERAL GEOLOGY

The accompanying table of formations and the geological map of
Barkerville area (No. 2046) show the nature and distribution of the rocks.
The consolidated rocks, consisting of various igneous, sedimentary, and
metamorphic types, form ridges and valleys trending northwest and with
the associated northeast cross-range structures control the somewhat
rectilinear drainage pattern seen on the map. Unconsolidated sediments,
of Tertiary, Pleistocene, and Recent times, obscure a considerable part of
the bedrock surface, but the general simplicity of regional structure enables
the geologist to exterpolate or project rock boundaries beneath the veneer
of regolith.

The only solid rock formation of determined geological age found in
the area is the crinoidal limestone of the Greenberry formation, which is
allocated to the Mississippian period. Basic sills and dykes, whose age is
tentatively assigned to the Jurassic, are in intrusive contact with the
uppermost member of the Slide Mountain series (which includes the
Greenberry formation). Below the Slide Mountain series, and separated
from it by an unconformity, is the well-known Cariboo series of doubtful
age, to the weathering of parts of which the formation of the gold of the
placer deposits is attributed.

Table of Formations

: ; Thick-
Period Formation Lithology ness
feet
Recent Sand, gravel, silt, muck, peat
Quaternary :
Pleistocene Glacial Boulder clay, morainic accum-

ulations, stratified five sand
and silt (‘‘slum”’), stratified
gravel and bouldery deposits.
cemented gravel

—EE

Interglacial Soil, gravel, lignite (?), strati-
fied glacial silt, and sand,
oxidized gravel

5 Tes
Unconformity

ee

Tertiary, gavel partly cemented, slide
roc

SSS et