Abstract
Galena and sphalerite occur in many places in eastern Ontario. A common type of occurrence is in well defined veins which cut vertically through beds as late as Ordovican. The veins show a decided banding with many vuggy openings along the central part. The greater part of the vein-filling is calcite in which the galena commonly occurs in crystals arranged more or less continuously along certain planes, but the planes are not themselves continuous. Sphalerite is intergrown with galena in varying proportions. The vuggy openings in the central part of some of the veins show a variety of minerals of the later vein stages. At the old Frontenac lead mine at Perth Road, Frontenac County, the openings in the vein contain well formed crystals of sky-blue celestite up to two inches in length. Marcasite is one of the late minerals to crystallize.
