Gypsum, with interbedded limestone, is exposed along the Bull River 4 kilometres upstream from the town of Bull River. Outcrops are restricted to the banks of the river, although a few sinkholes are present to the north and south.

The host rocks are believed to be Lower Mississippian Banff Formation sediments. Limestone outcrops extensively in the area, but contacts with the gypsum are not exposed. Black, nodular limestone, 5 to 15 centimetres thick, with shaly horizons, occurs north of the river. This limestone is lithologically similar to the Harrogate Formation in the Stanford Range (see 082JSW004, 082JSW021, 082JSW022, 082JSW028).

The gypsum is reported to be highly folded with local brecciation and faulting south of the river. The gypsum, exposed in old workings, is light grey to white-streaked in the upper part, grading to darker shades of grey towards the bottom.

About 317 tonnes of gypsum were shipped for testing in 1937 but no further development is recorded. The material analyzed approximately 30.5 per cent CaO, 39.20 per cent SO3, 18 per cent H2O, 2.5 per cent MgO, and 0.80 per cent Fe2O3 and Al2O3 (Reference undefined). A sample of gypsum collected in 1926 from across the face of the quarry analyzed 30.72 per cent CaO, 39.36 per cent SO3, and 19.36 per cent H2O (Ministry of Annual Report 1968, page 308).

In 1997, the Pleasant Surprise mineral claim was staked to cover three historical Crown Grants that came open for staking (Assessment Report 25678). The claims were owned by Charles Claude Downie. The claims consisted of 6 units and cover a package of Devonian to Mississippian limestones and dolomites and Precambrian Aldridge Formation argillite and quartzite. The claims straddle the lower part of the Bull River. One day was spent prospecting and 4 rock samples were collected in 1998. The Pleasant Surprise claims covered, in part, the Bull River gypsum deposit located on historical lease 7806. The deposit saw production in 1937 when 317 tonnes of gypsum was shipped for testing. The material analyzed approximately 30.5 per cent CaO, 39.2 per cent SO3,18 per cent H20, 2.5 per cent MgO, and 0.8 per cent Fe203 and Al203. The host for the gypsum is Lower Mississippian Banff Formation limestone. The historic Bull River mine (082NW002) is located about 1 kilometre east of the northeast boundary of the Pleasant Surprise claims. In 2000, Downie completed a one-day field program consisting of soil, rock and silt sampling, as well as 1:1000 scale geological mapping (Assessment Report 26323).