The sandstone quarry, located east of Nanaimo Harbour on Jack Point, produced building stone used to construct the Nanaimo Post Office (CANMET Report 452). No production figures are available.

The area is underlain by the Upper Cretaceous Nanaimo Group, Deadman River Formation.

The sandstone ranges from medium to dark blue-grey in colour and is medium-grained (0.6 to 2.0 millimetres). Cherty pebbles (up to 2 centimetres) and large sand concretions (up to 1.4 metres in dia- meter) disrupt an otherwise uniform texture.

In thin section, angular to subangular quartz grains between 0.25 and 1.5 millimetres in size comprise 50 per cent of the rock. A cloudy green chlorite cement is visible between grains of orthoclase which are often partially altered to sericite. Other constituent minerals include plagioclase, biotite and an unidentified isotropic mineral.

The original sandstone quarry described by Parks (1917) was not well exposed but recent excavations have removed large volumes of sandstone and exposed a 520 metre long face between 5 and 7 metres high. Distinct sets of joints are exposed, with the main set strik- ing northeast and dipping steeply northwest. Irregular west-north- west joints dip steeply to the northeast. Bedding planes strike par- allel to the face and dip moderately east. Greater than 60 per cent of the joints and fractures are spaced over 3.0 metres apart.

Reserves of sandstone, similar in appearance to the stone de- scribed extend 40 to 50 metres west of the worked face.