King Arthur’s Cave has been the focus of archaeological attention since 1870, when the Reverend Symonds excavated much of the [eastern] main chamber to the bedrock. An assemblage of early and later prehistoric flint tools, along with an array of faunal remains was retrieved. The western chamber was investigated by Taylor (1926-27) where the famous mammoth layer (comprising a stratigraphic sequence that included several hearth layers) was recorded. Again, the chamber was excavated to the bedrock. Much of the deposit that came from this excavation was dumped outside the entrance and survives today as a compacted spoil heap, which was investigated by Professor Nick Barton in 1993. Despite this antiquarian and archaeological activity, the various passages running northwards of the main eastern chamber have never been fully investigated. In 2021, a member of the First Art team (GHN), along with James Nash, discovered two haematite spreads on the wall of the western passage in an area aptly named the Sanctuary. This short paper discusses the discovery and verification processes that claims these two marks were applied to the Sanctuary wall by human agency and, second, both marks are probably of a later prehistoric date.