=L0=

Jurassic. Wo further information. regarding their poriod of
intrusion was obtained in the Manson Creek map-area, but in
the Takla map-area to the west the intrusions are apparently
of late Jurassic or early Cretaceous age. Wear Takla Landing
@ conglomerate of the Sustut group is composed in part of
pebbles and boulders of intrusive rocks lithologically similar
to the Omineca intrusions. Interbedded shales contain flora
of lower Upper Cretaceous age. On Kwanika Creek, a similar
conglomerate ea on the Omineca batholith. Wo fossils were

- found in it.

ae
A stock of medium- to coarse-grained pink syenite
intrudes the Omineca batholith north of Chuchi Lake. The.

rock is composed mainly of pink orthoclase and dark green
hornblende, and,.in part, is porphyritic.

This stock may represent a late phase of the
Omineca intrusions, or it may be much younger, possibly of
Tertiary age.

Tertiary

Dykes, sills, and flows of white and lavender
trachyte and rhyolite outcrop in séveral isolated localities.
They carry phenocrysts of biotite and feldspar in a fine-
grained groundmass. As these rocks cut all others in the
map-area they are probably of Tertiary age.

" STRUCTURAL GEOLOGY
Introduction

The sequence of sedimentary and “ail Gabe formations
of the Cache Creek and Takla groups has been established in
only 2 very general way in the Manson Creek map-area.
Lithological similarities in formetions of different ages,
scarcity of fossiliferous beds, great thicknesses of
structureless volcanic flows, paucity of outcrops: below
timberline, widespread extensive major and minor faulting,
and repeated folding resulting in steep, partly overturned
- beds have presented difficulties in the matter of stratigraphic
and structural interpretation that can only be solved by more
detailed studies than were possible on the Seater NOES
scale.

Folding

The regional trend of the formations of the Cache
Creek group and of the Wolverine complex is northwesterly.
Takla group rocks exhibit two regional trends: north of
Germansen Lake and east of Baldy Mountain road they strike
northwesterly, and north and south of Nation Lakes, westerly.

The rocks of the Wolverine complex, where examined
along Granite Creek and south to Manson River, strike from
north 35 degrees west to north 70 degrees west and. dip
southwest from 60 degrees to vertical. Drag-folding in
these beds indicates that the folds plunge to the northwest.

The regional trend of the Cache Creek formations
varies from north 30 degrees west to north 70 degrees, a Ue