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GENERAL GEOLOGY AND DESCRIPTION OF THE ORE OCCURRENCES!

. “The rocks underlying the limonite deposits are an assemblage of
basaltic flows and pyroclastics with some quartz diorite porphyrite dykes
and sills .. . . of Tertiary age . . (and overlie) un-
conformably the previously eroded surface of the great batholith of the
Coast mountains . . . . (from which they dip away) at angles
up to 25 degrees. . . . The Tertiary volcanic rocks also unconformably
overlie another voleanic series which is apparently cut by the batholith’.

“The deposits . . . . (of bog-iron ore) are situated in seven
different localities. They consist of sheets of brown limonite of varying
shape, size, and thickness, built up of thin layers of brown, cellular, and
generally loose-textured limonite, lying parallel to the surface of the
ground on which they rest. . . . The iron is derived from finely
divided pyrite which impregnates greatly silicified and sericitized tuffs
of the . . . . (Tertiary) formation. The iron sulphate solutions
formed by the oxidation and leaching of this pyrite trickle down the
mountain slopes and deposit (the iron) at the first favourable locality,
building up a bed of limonite.”’

“The limonite deposits in Taseko valley are . . . . ; the Forrest

deposit, located 6 miles from the source of Taseko river . . . . and
half amileeast of theriver . . . 3 Denain Creek deposit eee
on Denain creek 4 miles above its junction with Taseko river; Feo, Rae,
and Battlement Creek deposits . . . . ; the McC lure Mountain
deposits. . . . In area they vary from a few hundred to nearly a
million and a half square feet, and each deposit as designated above, com-
prises several separated areas of limonite. . . . In thickness the
limonite sheets range from a few inches to an ascertained dimension of
9 feet . . . . and it is probable that in some instances a thickness
of from 12 to 15 feet may be attained. . . . The surface of the limo-
nite beds where free from vegetation and not subjected to the action of
one of the numerous streamlets which characterize the deposits, is covered
with a loose . . . . gravelly ore layer. . . . up to a foot in
thickness and . . . . doubtless due largely to the disintegrating
action of frost. Below the loose surface layer the limonite lies in a coherent
mass . . . in layers slightly thicker with depth. . . . No
minerals other than earthy limonite have been recognized in any con-
siderable amount in these beds . . . . (which) are for the most
part bare of vegetation. . . . The range in Mle 5 5 o o (Or
the individual deposits) is from an elevation of 5,500 feet to over 7,300
feet . . . 3; no large beds are found above 8,400 feet.
Most of the beds lie on hill-sides of less than 15 degrees slope, many of
them much flatter than this. They usually occur on the valley walls
below where the steeper slopes flatten out into the more gently inclined
bottom of the valley. 2%

Te eats Miwa ce “Jimonite beds occur as patches lying on top of
the ground ... . and... . their deposition is still in
progress. . . . Their surface expression is such that they may readily
be distinguished from areas under by til . . . . (and it is'relat-
ively easy to accurately determine) the outlines of the deposits”. .

1 The quotations are from the report by J. D. MacKenzie.

17135—8