 In these locales, it occurs as thick beds of Paleoproterozoic pebble conglomerate within the medial part of a geologic formation that is named the Lorrain Formation of the Cobalt Group.The jasper conglomerate consists of subrounded pebbles of red jasper, black chert, white quartzite, hematite, and semi-transparent quartz in a matrix of coarsely grained quartzite.It contains circa 30% to 90% of pebbles.