24

The tuffs are interbedded with fine-grained argillites. Several poorly pre-
served fossil shells were seen in tuffaceous sandstones along the trail to
the camp at elevation 2,450 feet, and some shells are reported to have been
found in the mine workings.

LEGEND

Bedded tuffs,
argillite

Vein on
surface

Vein
underground

SCALE OF FEET
200 °

I
=
w
0)
nar
23.0
ys
ig
ar

Figure 4. Plan of part of American Boy group.

Five quartz veins occur along fault fissures traversing the tuffs and
argillites. Four of these veins strike roughly north and dip from 40 to 70
degrees east. The fifth and most southerly vein strikes northeast and dips
80 degrees southeast. The veins range from 4 inches to 4 feet in width,
and consist of quartz with occasional carbonate stringers, and with both
banded seams and irregular patches and bunches of sulphides scattered