90

The available evidence thus indicates that the Ingenika group is in
part, possibly in large part, of Lower Cambrian age. There is no further
evidence to indicate whether all of the rocks mapped in the group are of
the same age, or what range of age is represented. If the coral-like fossils
found west of the Beveley mineral claims are of Silurian or Devonian
age, as tentatively suggested by Dr. Okulitch, the rocks from which they
come should not be included in the Ingenika eroup.

As previously described, the Ingenika group rocks lie with angular
conformity on the Tenakihi group rocks, the contact between the two
groups being drawn below the stratigraphically lowest unit containing the
distinctive conglomerates characteristic of the Ingenika group. The top
of the group is nowhere exposed, and the overlying unmetamorphosed
rocks of late Paleozoic and younger age are faulted against the Ingenika
group beds.

CorRELATION

The Ingenika group rocks can be traced southeast from Aiken Lake
map-area to the valley of Omineca River, where McConnell (1896, p. 24)
correlated the conglomerate, quartzites, and slates with the Bow River
series of Lower Cambrian and Precambrian age, and the limestones with
the Castle Mountain group of Middle Cambrian to Cambro-Silurian
(Ordovician) age. McConnell found no fossils, and based his correlation
with the type area, some 450 miles to the southeast, on lithological
similarity alone.

The archaeocyatha in Tenakihi Range indicate a correlation with the
Donald formation, the uppermost Lower Cambrian formation of the
Purcell Mountains (Evans, 1933, p. 122), and the equivalent of beds in the
lower part of the series of formations now considered to correspond with
the Castle Mountain group of McConnell. Okulitch (1949) has summar-
ized the relations between lithological equivalence and fossil correlation
of the Precambrian and Cambrian rocks of that part of the Cordillera 300
miles southeast of Aiken Lake map-area, and his suggestion of an east-
ward-migrating geosyncline in Late Precambrian and Cambrian time,
supplied mainly by sediments from a retreating eastern shore of fairly
high relief, is compatible with the meagre evidence regarding the origin
of the Tenakihi and Ingenika groups.

In the Cariboo Mountains, about 250 miles southeast of Aiken Lake
map-area and in much the same regional geological setting, beds of
quartzite and limestone contain a Lower Cambrian trilobite fauna (Lang,
1938, p. 14).1 These beds may be correlative with the Ingenika group
beds, and they overlie with apparent conformity the Cariboo series, which
may correspond with the Tenakihi group, and which like it is, presumably,
of Precambrian age.

In the Toad River-Muncho Lake area along the Alaska Highway,

130 miles due north of Aiken Lake map-area, Williams (1944) and
Laudon and Chronic (1949) found a thin series of tan quartzites and sand-

1In 1953, archaeocyatha ‘similar to those found in the Ingenika group were collected from similar
beds in the Cariboo Mountains by A. Sutherland-Brown of the British Columbia Department of
Mines (V. J. Okulitch, personal communication, 1953).