14

level of Kinskuch lake the rocks are much altered, contain much pyrite
and magnetite, and have been greatly shattered and break into small, angu-
lar pieces. Some appear to be tuffaceous sediment and some are fine
grained and are either a lava flow or an intrusive. West of Kinskuch lake
although the rocks are chiefly fragmental types with augite porphyrite
fragments there are also some fine-grained, amygdaloidal, purplish, ande-
sitic lava flows, and very fine-grained rocks and felsites.

The felsitic tuffs and breccias of the part of the Theophilus body east
of the head of Illiance river lie in a northerly striking anticline at least
1 mile wide. The anticline has not been traced to the south end of the
body. To the north it flattens and east of Kinskuch lake near the north
end of Theophilus body the rocks dip gently east. Along the northerly
trending part of Illiance river the rocks are sheared and appear to be
sharply flexed. The prevailing dips along the valley are steep to the west.
Farther west in the central part of the body the felsitic breccias are well
bedded and over a width of 2 or more miles have gentle southerly dips.
Still farther west the felsitic tuffs and breccias of Theophilus mountain and
those of the mountain to the north dip east at moderate angles. Farther
north in the vicinity of Kinskuch lake the dips are gentler to the east.
Along the west side of the body the rocks are augite porphyrite breccias.
They also dip east at moderate angles and pass under the felsitic frag-
mentals. The contact between the augite porphyrite breccias and the
felsite breccias, etc., is very difficult of access and consequently has been
examined in detail in only a few places, but there can be no doubt that the
augite porphyrite breccias are the older. In the southwestern part of the
Theophilus body sediments lie between the two types of voleanic rocks,
but farther north the felsite breccias directly overlie the augite porphyrite
breccias. Immediately west of Theophilus mountain the band of sedi-
ments is about 1,200 feet thick, but it narrows to the north and ends 2
miles north. While these sediments were being deposited it is probable
that volcanic rocks were being accumulated farther north. Judging from
the admixture of felsitic rock in the breccias of the augite porphyrite
type, particularly near their top, it appears that there was a gradual change
in type of volcanic extrusive from an early predominantly augite por-
phyrite type to a late dominantly felsitic type. The small stock of augite
porphyrite on the south slope of Theophilus mountain intrudes the basal
members of the felsite breccias and shows that although the predominant
eruptive at that time was felsitic there were still local eruptives of augite
porphyrite.

West of the Theophilus body, between it and the Kitsault body, are
four small bodies of igneous rock. Two lie immediately south of Clear-
water lake near the north end of Alice Arm district and consist of rudely
bedded, felsitic, fragmental rocks. These two bodies appear to overlie the
adjacent sediments and probably were formerly joined to the nearby
breccias of the Kitsault body. The thickness of volcanic rocks in the
bodies probably does not exceed 300 feet. Erosion has cut through them
exposing the sediments below and separating these bodies from the Kit-
sault mass to the west. The third body lies near the western edge of the
Theophilus body at the head of Dak river. This body is an intrusive stock