The Brassington Formation is a geological formation in the United Kingdom, and the country's most significant onshore Miocene deposit. it is preserved as around 60 inliers in karsts of Carboniferous limestone, specifically the , in a triangular region on the borders of the Staffordshire and Derbyshire counties. The lithology largely consists of unconsolidated sand with clay and minor silt components. Pebble beds are also a significant component. It is divided up into three members, which are in ascending order the Kirkham Member, Bees Nest Member and the Kenslow Member. The Kenslow Member is dated to the Serravallian to Tortonian stages based on palynology.