The Spider showing is located on the northwest of Sleeper Mountain, 5 kilometres due west of Grant Brook on the Canadian National Railway between Tete Jaune and Jasper.

The geology of the area has recieved considerable attention in recent years. Detailed mapping has been primarily conducted by E.W. Mountjoy in the Rainbow Range from 1964 to 1968. M.R. McDonough, more recently conducted detailed mapping in the northernmost Selwyn Range.

Three informal map units have been recognized within the Hadrynian Miette Group of the northernmost Selwyn Range. The lowermost consists of a pelite and quartzite succession assigned to lower Miette status. This strata underlies a thick sequence of massive conglomeratic sandstones (grits) and green pelites belonging to the middle Miette. The upper Miette consists of a sequence of dark calcareous pelites and black limestone with minor sandstone.

North of Sleeper Creek, thick conglomerate and sandstone units form a channel-like feature that cuts into and eliminates the underlying pelite unit. Thick conglomerates were deposited by mass gravity processes, likely representing debris and grain flows, and developed channels in an anastomosing submarine fan complex.

The structure of the area is dominated by a series of large, upright F2 folds that form an anticlinorium in the Moose Lake Thrust, which truncates in the west limb of the Mount Robson Synclinorium. Pelites of the lower and upper Miette are thickened primarily by folding and foliation development. Middle Miette strata are thickened by folding and thrust faulting. Pre F2 folding, bedding parallel thrusts also thicken middle Miette strata. This was first recognized by McDonough and Simony (Geological Survey of Canada Paper 88-1D, pp. 105-113).

Metamorphic grade, in the area, decreases to the north and northeast into the biotite zone with scattered chloritoid of greenschist grade.

At about 1402 metres, the massive conglomeratic sandstone beds of the middle Miette unit, host small quartz veins. A vein 15 centimetres wide is well mineralized with galena and lesser sphalerite. A sample from one of these mineralized veins assayed trace gold, 360 grams per tonne silver, 62 per cent lead and 1 per cent zinc (Minister of Mines Annual Report 1927).