The Watson Bar zeolite showing occurs within poorly exposed felsic volcanic rocks which may be correlated with the Kamloops Group of Eocene age, east of the Fraser River. These rocks form an overlap assemblage on both Methow and Cache Creek terranes. The close spatial relationship of zeolite occurrences and faults of the Fraser fault system suggests that these faults provided channelways for that hydrothermal solutions that caused zeolite alteration of the volcanics.

Heating of a sample, taken from the Watson Bar showing, at 475 degrees celsius for 16 hours indicates that the zeolite mineral is clinoptilolite-rich.