The South Mooney's zeolite showing is within volcanic rocks of Eocene age which are correlative with Kamloops Group to the east. These volcanics represent an overlap assemblage on Methow and, east of the Fraser Fault, Cache Creek terranes.

The showing is within a steeply dipping sequence of acid volcanic breccia, and locally layered tuffs. Heating samples at 525 degrees celsius, for 16 hours indicates that the clinoptilolite end member of the heulandite-clinoptilolite series is present. Exchangeable cation analyses expressed in milli-equivalents per 100 grams, is Ca 18.75, Mg 0.53, Na 23.75, and K 18.75. The cation exchange capacity (CEC) 58.5.