The Hallidie occurrence is underlain by west striking, 15 degrees south dipping conglomerate and greywacke of the Lower Cretaceous Queen Charlotte Group. Locally, a 1.5 metre coal seam was encountered while drilling in Coal Harbour. Another 0.60 metre wide coal seam of fair quality is reported on the west side of Coal Harbour (Geological Survey of Canada Paper 74-8, page 73). The same seam also outcrops 3.6 kilometres northeast of Hankin Point on Rupert Inlet, 5.5 kilometres east of the Hallidie occurrence. At that location, three coal seams are 15 centimetres, 15 centimeters and 2.5 centimeters thick and are separated by about 1 metre of shale. The location hosts Albian microflora fossils. The grade of the coal is not reported.