The pipes, and associated dikes of similar composition, intruded the crystalline basement along a northeast structural trend. Both pipes are small with diameters of less than 225 meters. Both dip to the southeast and can be traced down dip approximately 300 meters. The two pipes, termed the East and West pipes, are connected by a narrow arcuate dike of similar composition to the pipes. The Precambrian host rocks have been sheared and altered within 30 meters of the intrusive.
Alteration takes the form of sericite, pyrite and less commonly clays.
The intrusive is mapped as felsite, but geochemistry indicates the rock is a rhyolite. The rhyolite represents the first phase of intrusion. Subsequently, the rhyolite, gneissic host and overlying clastic sedimentary units were brecciated and the fragments incorporated in a second pulse of rhyolitic magma. The West pipe underwent yet a third phase of brecciation which resulted in a rubble breccia of carbonate and clastic sediment clasts in a rock flour matrix. This unit is termed a sediment clast breccia and is easily recognized by the extensive pyrite replacement of the carbonate clasts.