The Silver Creek occurrence area is underlain by Lower Paleozoic mica schists, quartzites and small bands of fine grained crystalline limestones cut by numerous dikes, sills and irregular bodies of Devonian gneissic granitic rocks.
In Woolsey (Silver) Creek, about 2.4 kilometres below its confluence with West Woolsey Creek, a highly altered, dark grey, fine-grained "lamprophyre dike" consists of biotite, quartz and calcite. Fluorite and quartz fill amygdules (Geological Survey of Canada Summary Report 1928 Part A, page 149).