77

farther west, at Steamboat Island (See Figure 11), it reappears in easterly
dipping ledges above river level, and outcrops on the island, on the river

bank, and on the valley slopes. Here Beach and Spivak measured the
following section:

Thickness
Feet
Sandstone, crossbedded, platy; plant fragments seecen een eee 75
Sbalesblacktaten Sea. ete rh ARE RS am BRE eee te 60
Sandstone, massive, quartzitic........................00000.. 30
SIG Gos ee aan O GUS TON MOS RCN Camel oie eae eta es nie 75
Sandstone reir ca moe an ae ee on EE DOC A A 5
DRO Ro oR ae CHA OMIS Hic a DOOR SAH MER Meret teen 245

From the uppermost sandstone of this section the geologist of an oil company
collected specimens of marine pelecypods, including species of Ostrea,
Pecten (Entolium), and Arctica?.

On Johnson Creek, Beach and Spivak (1944) measured 430 feet of
sandstone and shale in the Gates formation. On Coalbed Creek, a tributary
of Johnson Creek, they collected Beudanticeras sp. and other fossils from
the Gates or basal Hasler formation.

Little is known of the extension of the Gates formation north of Peace
River. Dresser (1921, 1922) describes exposures of sandstone on Farrell
Creek, near the forks. These overlie the thick section of shale and sand-
stone penetrated in bore-holes at that locality previously referred to in
describing the Moosebar formation. Although no proof of identity, based
on fossils, exists, it is possible that this sandstone is a northern continuation
of the Gates. This formation does not appear to extend as far north as
Sikanni Chief Valley; at least it has not been recognized by Hage (1944).

Although some evidence of non-marine origin has been noted (McLearn,
1918), it is evident, from the entombed marine fossils, that most of the
Gates formation is of marine origin.

Commotion Formation

South of Peace River Valley, the Commotion formation is partly the
equivalent of the Gates, but appears to include higher beds; it contains
beds of coarser texture than the Gates, and consists of about 1,300 to 1,500
feet of marine and non-marine sandstone, conglomerate, and shale, with
rare, very thin coal (Wickenden and Shaw, 1943). It lies conformably
between the shales of the Moosebar below and the shales of the Hasler
formation above.

In early reports on the Pine River and adjacent areas, the beds of the
Commotion formation were placed in the Bullhead group, and the thick
conglomerate exposed in the lower part of Commotion Creek was called
the Boulder Creek Conglomerate member (Spieker, 1921). Later, how-
ever, it was realized by geologists studying the Fort St. John group that they
were not only distinct from any part of the Bullhead, but actually overlay
the Moosebar formation (Williams, 1940; Stelek, 1941; Wickenden and
Shaw, 1943). It was realized also that their stratigraphic position was
much like that of the Gates formation of Peace River Valley, but because
of their greater stratigraphic range and somewhat different texture, it was
inferred that they could not be placed in the Gates, but must be incorporated