64

Pine River and Peace River Foothills

Table of Eastern Formations

Group Formation | Thickness Lithology

Feet

Gething 1,400+ Non-marine sandstone and shale; coal seams

Bullhead =

Dunlevy 3,000 Non-marine conglomerate, sandstone, and to shale; thin coal seams above; partly ma- 3,200 rine?, massive, thick-bedded sandstone;

some shale below.

Dunlevy Formation

The Dunlevy formation is well exposed in the eastern part of the Peace River Foothills, on Portage Mountain, on Butler Ridge, in the upper part of Peace River Canyon (See Plate VI A), on the lower slopes of Mount Gething, on Branham Ridge, and in the ridges and cliffs of Rainbow Rocks. For the purpose of description it may be divided into two parts, a lower and an upper.

A section of the lower part was measured by Beach and Spivak (1944) on the lower slopes of Mount Gething, where it consists of 2,440 feet of mostly thick-bedded, very hard, fine-grained, quartzitic sandstone inter’ edded with dark, carbonaceous shale. Some sandstones are massive, others are b dded, and some are crossbedded. Some are brown and somewhat carbonaceous. The sandstone beds are from 10 to more than 100 feet thick. The shale beds are thinner, and vary from very thin to beds more than 25 feet thick; an exception, however, is a bed or zone of shale 143 feet thick, about 700 feet above the base of this section. Beach and Spivak note that at least 200 feet should be added to the thickness of this part of the formation at this locality to account for concealed beds between the top of the section described and the base of the upper and conglomerate-bearing part of this formation. The contact with the underlying Fernie group is gradational.

The upper part of the Dunlevy formation differs from the lower part in the presence of conglomerates and thin coal seams. Beach and Spivak (1944) record 400 to 600 feet of “massive, crossbedded, coarse-grained, grey to reddish weathering, conglomeratic sandstones and grits, in beds 5 to 20 feet thick, interbedded with 6-inch to 2-foot beds of buff weathering, fine-grained sandstones, carbonaceous shales, and thin coal seams. Some beds consist entirely of conglomerate with pebbles up to 2 inches in diameter and averaging 3 inch. The pebbles are angular to subrounded, and consist of green and black chert, white quartz, and quartzite. Individual con- glomerate beds are commonly lenticular and wedge out rapidly along the strike of the beds”. Beach and Spivak measured 400 feet of the con- glomerate member on Mount Gething and at least 600 feet on Butler Ridge. McLearn and Irish (1944) record conglomerates, fine sandstones, siltstones, dark shales, and thin coal seams. Some of the fine sandstones and silt- stones in this upper part are ripple-marked, and carry fossil wood fragments and fine plant debris. The toal thickness of the Dunlevy formation is estimated by Beach and Spivak to range from about 3,000 to 3,200 feet.