A horizon from the Cambrian of British Columbia which has yielded an exceptionally preserved fauna. Originally discovered by C. D. Walcott in 1909, it has been redescribed by H. B. Whittington and other authors (1967–8). Apparently the fauna was deposited in deep water on or near a submarine fan. Arthropods of various types account for more than 30% of the fauna, but other groups are also represented, many of them bizarre. It is probable that in terms of its diversity (140 species in 119 genera) this was a typical Cambrian fauna, but it is unusual in that the soft-bodied forms are preserved.