The Big Bend deposit is located on Lot 6182 along the east side of the Fraser River at the big bend, 12.8 kilometres north of Quesnel. The largest diatomite deposits in British Columbia occur in this area.

The area has been disrupted by faulting and the diatomite occurs as rather small disconnected blocks at various elevations. It is likely that the diatomite was originally laid down at the same elevation in lakes formed by obstructions in the Tertiary Fraser River. The diatomite, believed to be lower Upper Miocene in age, overlies older Tertiary clays, sands and gravels. The diatomite consists almost exclusively of various sizes of Melosira granulata diatoms, usually very small, with variable amounts of clay, silt and volcanic ash. The diatomite ranges in colour from white to grey to buff.

There are three major exposures of diatomite on Lot 6182. Small lots of the diatomite have periodically been shipped to Vancouver for making insulating brick.

A 3 to 6 metre bed of white stoneware clay underlies the diatomite. The deposit occurs close to water level at the downstream end of the big bend. The clay is interstratified with other clay and sandstone members of the Tertiary Fraser River series and is exposed for about 440 metres along the river. The clay deposit is on average 3 to 3.5 metres thick and dips gently to the south.

A sample of the clay had good plasticity and dried safely at 85 degrees Celsius. It fired to a hard cream body at cone 2, had a softening point at cone 16 and was classified as suitable for the production of sewer-pipe, flue-linings etc.