A single coal seam is present in an unnamed unit of Eocene to Oligocene age, interbedded with shale and sandstone (Unit Tsh, Geological Survey of Canada Paper 90-10, pages 31 to 50, Figure 9). The seam is lenticular (merging along strike into black shale and ironstone) and varies in thickness from 0 to 1.8 metres (average 0.9 metre). The seam is repeated by faulting so that at the Hooper workings two exposures of the seam, 0.76 metre and 0.15 metre thick, occur stratigraphically above the main seam. The coal is a bright semi-anthracite.

The strata are close to vertical and faulting is common with local disturbances of the strata. The coal occurs in close proximity to the underlying volcanics.

A coal seam approximately 1.5 metres thick occurs on King Creek, 0.4 kilometre northeast of the Hooper Creek openings. The coal is anthracite and is fairly clean. The seam here occurs 152 metres above the base of the Haida Formation and may be a continuation of the Hooper Creek or Slatechuck (103F 016) seams. Dips are steep in the area.

Analyses from the Cowgitz coals indicate volatile matter ranging from 4.77 to 8.14 per cent, fixed carbon 74.09 to 85.76 per cent, ash 6.69 to 14.16 per cent and sulphur 0.89 to 1.53 per cent.

Work done includes three major adits, three short adits, three small shafts - a total of 335 metres of crosscutting and 152 metres of drifting on coal with only a few hundred tons of coal shipped. British Pacific Coal Company, Limited produced 32 tonnes in 1912.

The showing, located at an elevation of 305 metres near the headwaters of Hooper creek in the vicinity of Skidegate inlet, was discovered in 1859.

In 1865, the showing was opened up along a 0.6-metre seam by the Queen Charlotte Coal Mining Company, Limited. The property was abandoned in 1872.

In 1912 the caved workings were examined by The British Pacific Coal Company, Limited.

Analysis of the 0.6 metre seam showed: water 1.6 per cent, volatile matter, 5.02 per cent; fixed carbon, 83.09 per cent; ash 8.76 per cent; sulphur, 1.53 per cent ; and a fuel ratio of 16.5. A preliminary estimate of probable mineable reserves by Mackay for the Royal Commission on coal, in 1946, was 3,3609000 tons.

Based on an average coal seam thickness of 1.8 metres (from at least three different seams) underlying an area of 2.6 square kilometres, the coal reserve of the Cowgitz prospect is about 3.25 million tonnes (Geological Survey of Canada Summary Report 1912, page 37).