The Stratigraphy of the deposits in Picken's Hole. (UBSS Proceedings v.27(3))

Abstract: The nature and sequence of deposits encountered during the excavation of Picken's Hole are described based on field observations during excavation and available records. Six units are recognised from Unit 6 at the base to unit 1 at the top which includes the present-day soil. Unit 6 presents an irregular top surface and a range of deposits from clays and free sandy material to densely cemented limestone breccia sometimes with significant voids, but often transitional to in situ bedrock. Unit 5 is a relatively thin unit and becomes patchy or absent to the south. It comprises a variable assemblage of reddish clay loams in places with weathered limestone, and generally abundant heavily mineralised and very broken bone. Species present include brown bear, wolf, red fox, reindeer and a large bovid, but hare, gregarious vole, northern vole, bird and frog bones also occurred. Unit 4 comprises an angular limestone breccia with limited weathering, and a grey yellow to brown sandy matrix. Where it overlay Unit 5 the base contained blackish animal bones and teeth, including wolf, red and arctic fox and reindeer. Elsewhere, Unit 4 rested directly on Unit 6, from which it contained cemented clasts. Unit 3 is a maximum of 80 cm thick and comprises yellowish clay to sandy loams as matrix within highly weathered limestone breccias. There is evidence for local topographic control of some contexts, with dips towards the south, and infill of a depression formed against the cliff. Substantial amounts of fragmented yellowish and largely un-weathered animal bone and teeth were present, mainly in the lowest 50 cm of the unit. Finds were dominated by spotted hyaena, woolly rhinoceros and horse, but apparently included 2 human teeth. Unit 2 comprises a variable sequence of matrix rich breccias and more clast free reddish brown clay silts. The angular limestone clasts lie horizontally and are more weathered at the top of the unit. In square D the unit overlies a thin yellow silt over bedrock. Unit 1 includes the modern soil. Unit 1 lies unconformably over the eroded remains of Unit 2 and 3 to the west and north of the site, but appears to be conformable on Unit 2 in the south of square B. The soil comprises turf and topsoil above a somewhat bleached horizon, with a brown more clay rich unit including weathered limestone clasts at depth. The deposits have been affected by the burrowing activity of badgers, the distribution of which is described in an Appendix.