Ancholme Group

The Ancholme Group is a geologic group in England. It preserves fossils dating back to the Jurassic period. It has previously been referred to as the Ancholme Clay Group. The group consists of predominantly grey, marine mudstone and silty mudstone with beds of argillaceous limestone nodules.
It passes in a North-Eastern line through southern England, passing through Peterborough, Oxford, and the Cotswolds. The rock within it dates to the Callovian - Oxfordian (166.1 - 157.3 million years ago).