Loss Creek flows west along the Leech River Fault, which separates Jurassic to Cretaceous Leech River Complex (Formation) slates and schists to the north, from Tertiary Metchosin Volcanics to the south. The metasediments strike nearly west and dip steeply northeast.

The topography shows that the Loss Creek has cut down through the bedrock, leaving a series of gravel covered benches. Placer gold, found in the gravel, is believed to have been derived from small, but numerous, gold-bearing quartz stringers hosted by the Leech River rocks.

Bulletin 21, from 1946, states that placer miners have worked the following rivers and streams of Vancouver Island: China and Loss creeks, and Leech, Gordon, Jordan, Sooke, Sombrio, San Juan, Bedwell, Nanaimo, Gold, and Zeballos rivers.

The Spaniards first identified gold in the area in 1792 (see Sombrio Point Placers, MINFILE 092C  044). The placer deposits were re-discovered in the late 1800’s in association with placer gold exploration on the island, following the discovery of the Leech River Placers (MINFILE 092B   078) in the 1860’s. Minor work by local prospectors has continued through to present. The lower part of the creek is located in Juan De Fuca Provincial Park.