Within Eocene volcanic rocks on the eastern margin of the Chilcotin Plateau are deposits of volcanic glass which, in both hand specimen and thin section has the characteristics of perlite. Most of the volcanic rocks of the region are breccias and tuffs but in some areas volcanic flows in which the matrix is mainly glass have been extruded.

The Ward Creek glass showing is a subvertical flow which yields about 9 per cent H2O but is not expandable upon heating. To the northwest, there is no outcrop between this occurrence and that of Mooney's Ranch (092O 104). It is likely, however, that both occurrences are part of the same, mainly drift covered, flow.