Ninety-nine Ordovician oil shale localities have been found on Southampton Island, extending from Duke of York Bay south to Sixteen Mile Brook and east to the East and Junction Bay areas, a distance of about 200 mi (322 km). The shales tend to occur in a linear belt near the Ordovician/Silurian contact. In almost all cases the shales occur as minor constituents of carbonate rubble. Outcrops and/or drilling indicate that the shale is interbedded with carbonates over a 50 ft (15 m) interval in high Richmondian strata at or near the top of the Churchill River Group. Analyses up to 35 gallons of oil per ton have been determined, with analyses averaging about 13 gallons per ton. Oil shales have also been reported from a slightly lower horizon, between the Churchill River and Bad Cache Rapids Groups — approximately Edenian and/or Maysvillian. Analysis and areal extent of these are not known.