The Brigade Creek rhyolite ash and bentonite occurrence is located on an old logging road on the west side of the Deadman River valley access road, approximately 5 kilometres west of Skookum Lake. The area is approximately 45 (air) kilometres north of Savona, and is accessible on a good-quality gravel road which leads north from the Trans-Canada Highway approximately 7.4 kilometres west of Savona. Access is also good on logging roads via Loon Lake to the northwest.
Basalts of the Miocene Chasm Formation (Chilcotin Group) mantle most of the area. However, beneath the basalts, massive rhyolite ash of the Miocene Deadman River Formation (Chilcotin Group) is exposed in cliffs in the Deadman Valley to the east for a length of several kilometres. The rhyolite ash is the predominant lithology in a Miocene channel filling of fluviatile and lacustrine sediments occupying the northwest trending Mio-Snohoosh Channel (Open File 1989-21). The flat lying Mio-Snohoosh channel is more than 200 metres in thickness and the best exposures of the rhyolite ash sections are on the north side of Sherwood Creek (092P 093).
At the Brigade Creek showing, chips of rhyolite ash and diatomaceous earth occur in a cut bank which is underlain and overlain by basalt flows of the Chasm Formation. The distribution of basalt outcrops permits the presence of up to a 10 metre thick rhyolite ash and diatomaceous horizon which belong to unit Mcr of the Chasm Formation (Open File 1989-21).