The Mowich Lake/Moose Creek diatomite showings are located between Mowich Lake and Moose Creek on the west side of Deadman River, 60 (air) kilometres northwest of Kamloops. Access is by secondary and old logging roads.

Read (Open File 1989-21) has described four occurrences of diatomite in a north-trending zone within 1 kilometre of each other. The occurrences are hosted within interlayers in Miocene flows of the Miocene Chilcotin Group plateau basalts. Comments on the individual occurrences follow: At the Moose Creek South 1 occurrence, blocks of diatomaceous earth occur in a ripped-up landing in a logged area. Oil immersion mounts were made of samples from blocks of diatomaceous earth to confirm the nature of the occurrence. The dimensions of the occurrence are not known, however, it is located between basalt flows of the Chasm Formation (Chilcotin Group).

The Moose Lake South 2 occurrence is also hosted by an interlayer within basalts of the Chasm Formation. It is exposed in a cut-bank about 13 metres high filled with diatomaceous chips. Chips of bedded rhyolite tuff and diatomaceous earth form a layer of bedded tuff and diatomaceous earth which is at least 15 metres thick.

The Mowich Lake 1 occurrence is located at the end of an old logging road, where the roadcut exposes the diatomaceous earth. The interflow layer lies within 10 metres of the top of the Deadman River Formation (Chilcotin Group). The thickness of the layer is unknown, but the same layer probably outcrops 300 metres distant at the Mowich Lake 2 occurrence.

The Mowich Lake 2 occurrence is also exposed in a roadcut in an old logging road. It also is hosted by the Deadman River Formation. The petrography of the showing was identified in oil immersion grain mounts. The thickness of the occurrence is not known.

No work is known to have been undertaken on the occurrences.