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are products of the early stages of deformation. As stated above, in very
many places quartz stringers of the A vein type occur in and adjacent to
sills of Proserpine quartz porphyry; and this fact, together with the occur-
rences of sheared and unsheared sills, suggest a genetic relationship between
the A quartz and the Proserpine sills.

B Veins

The B veins are quartz-siderite-ankerite fillings of the northeasterly
trending cross-range fissures and faults, and although they are, relatively
to the A veins, inconspicuous features of the geology on account of their
narrowness, they are important features because of their mineralogy and
abundance.

Northeasterly trending fissures and faults occur in all parts of the area
and cross all the bedrock formations, but only where they are found cross-
cutting the Cariboo series and the Proserpine sills are they mineralized with
quartz and metallic sulphides. The resulting veins vary in thickness from a
fraction of an inch up to about 5 feet, and there are very many of them over a
foot thick. Their average strike is north 25 degrees to 35 degrees east, but
a few of them strike nearly north, whereas others trend north 60 degrees to
65 degrees east. As a rule they are quite continuous along their strike, as
far as can be judged from their relatively unsatisfactory exposures. They
are characteristically cross-faulted, so that each vein contains several minor
sidewise offsets of a few feet, but none of these is of sufficient magnitude to
interfere with the general continuity and exploration of the vein. In many
places, B veins occur in closely-spaced parallel groups cutting across the
foliation of the members of the Cariboo series, as at the Black Jack open-cut
on Williams creek, where twenty-five of them from 2 to 10 inches thick
were counted in a total width of 50 feet. The fractures in which the veins
occur not only traverse the Cariboo series, but pass through the A veins,
and produce in the latter the cross-vein, sheeted, or platy structure com-
monly seen in the A quartz.

The minerals of the B veins are quartz, siderite, and ankerite, with
galena, arsenopyrite, pyrite, scheelite, and minor amounts of sphalerite,
and pyrrhotite. The quartz is not sheeted or platy like the A type, and has
not been subjected to the same intense shearing stresses. Arsenopyrite and
galena occur in many of the veins in considerable quantities, and scheelite
is commonly disseminated in grains or collections of grains as large as
walnuts, especially in the northwestern and southeastern parts of the area.
Pyrrhotite was found to be sparingly present in a few of the veins in the
Mosquito Creek hydraulic pit; sphalerite has been recognized from some
of the B veins on Proserpine mountain.

Both the arsenopyrite and pyrite are auriferous. Assays of selected:
material show the pyrite to carry as much as $10 to $12 a ton; the
arsenopyrite contains gold values as high as 140 ounces a ton of pure
mineral. (For details of these samples, See description of ledges on Proser-
pine mountain, pages 195-205.) The galena contains on the average about
one-half ounce of silver to the unit of lead.

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