Situated on an abandoned railway siding near Upper Twin Lake is a wide
calcite-
quartz vein mineralized with minor
pyrite,
arsenopyrite and
smaltite. This mineral showing, known as the Upper Twin Lake Occurrence, is hosted in
diabase of a
Nipissing sill just north of a
contact with pebbly
greywackes and
conglomerates of the Coleman Member of the Gowganda Formation. The vein strikes in a southeast direction and is traceable for a distance of . Sampling has indicated low
silver and
copper values with 50 parts per billion
platinum and 30 parts per billion
palladium. ==See also==