Eocene volcanic rocks near the eastern margin of the Chilcotin Plateau but west of the Fraser River are correlative with the Kamloops Group to the east of the river. Although most of the volcanic rocks comprise breccias and tuff, in some areas glassy volcanic flows are exposed. The volcanic glass, both in hand specimen and thin section has the characteristics of perlite.

The Mooney's Farm occurrence is a road exposure of volcanic glass isolated by drift from another outcrop of volcanic glass (Ward Creek - 092O 105) with which it may connect under the drift cover Chemical analysis shows that this glass contains about 9 per cent H2O but is not expandable upon heating.