Scarborough geological watching brief : Toll House Shaft site, Castle Hill SSSI

This report presents the results of a study by the British Geological Survey (BGS) to carry out a ‘Geological Watching Brief’ for the Scarborough Revised Bathing Water Directive works at the Toll House Pumping Station shaft site, Scarborough, a designated geological Site of Special Scientific Interest (SSSI). The research was carried out on behalf of Arup for Yorkshire Water Services Ltd. during the sinking of the Toll House shaft in spring/summer 2013, and included conjunctive studies of site investigation borehole cores and gamma-ray logs drilled at the site and the surrounding area in 2011. Study of the site investigation boreholes cores, ganmma-ray logs and shaft geology provided new information on the Jurassic Callovian-Oxfordian succession, only part of which is currently exposed at the South Toll House Cliff geological SSSI.The geological findings have both scientific and historical-scientific value, because the lower part of the Callovian succession on the lower foreshore, which was studied by pioneering 19th century geologists, has not been visible since the construction of Marine Drive (1897-1907) and more recent rock-armouring of the foreshore. Site investigation borehole cores from the site were slabbed and curated at BGS Keyworth. The following succession (up to 41 m thick) was proved in the boreholes, in downward sequence: the lower part of the Lower Oxfordian Oxford Clay Formation (Weymouth Member); the Callovian Osgodby Formation, including the Hackness Rock, Langdale and Red Cliff Rock members); the Early Callovian Cayton Bay and Cornbrash formations, and in one borehole, the underlying Bathonian Scalby Formation. The slabbed core was sampled for palynology, macrofossils and petrology.