Within Eocene volcanic rocks on the eastern margin of the Chilcotin Plateau, equivalent to the Kamloops Group volcanics to the east, are deposits of volcanic glass which, in both hand specimen and thin section, have the characteristics of perlite.

The Moore Lake showing consists of flow banded, slightly porphyritic (plagioclase, hornblende, biotite) flows containing about 9 per cent water but not expandable upon heating. Farther to the northwest along the sample zone one of the samples collected is expandable upon heating to about 50 per cent of that of Aurun Mines perlite deposit near Empire Valley (Open File 1988-29).