The Similkameen Bentonite prospect is 400 metres east of the Similkameen River, 7 kilometres south-southwest of Princeton.

The deposit is situated near the eastern margin of the Princeton Basin, a northerly striking fault-bounded trough filled by Eocene volcanic rocks of mainly intermediate composition, comprising the Lower Volcanic Formation, and an overlying Eocene sedimentary sequence of sandstone, shale, waterlain rhyolite tephra (tuff) and coal, up to 2000 metres thick, comprising the Allenby Formation.

The bentonite is hosted in a shale member in the upper part of the Allenby Formation (Princeton Group), known informally as the Ashnola shale (Open File 1987-19). The bentonite contains several thin sandstone beds in surface exposures. Drilling encountered a zone of sandy bentonite, 9 metres thick, at shallow depth. Two samples collected from drill holes averaged as follows (in per cent) (Paper 1983-3, page 20):

____________________
SiO2          70.20
Al2O3         13.78
Fe2O3 + FeO    3.59
MgO            1.84
CaO            2.03
Na2O          <0.30
K2O            0.20
TiO2           0.197
MnO            0.017
P2O5           0.036
H2O (105 C)   8.00
H2O (>105 C) 10.00
____________________

This prospect was geologically mapped and drilled (3 holes) by Benpel Industries Ltd. in 1973. Western Industrial Clay Products operated the Bud bentonite quarry in 1999. Absorbent Products Ltd. operated the quarry in 2010.