The Mercia Mudstone Group is an early Triassic lithostratigraphic group which is widespread in Britain, especially in the English Midlands—the name is derived from the ancient kingdom of Mercia which corresponds to that area. It is frequently encountered in older literature as the Keuper Marl or Keuper Marl Series.

Cheshire is a ceremonial county in North West England. It is bordered by Merseyside to the north-west, Greater Manchester to the north-east, Derbyshire to the east, Staffordshire to the south-east, and Shropshire to the south; to the west it is bordered by the Welsh counties of Flintshire and Wrexham, and has a short coastline on the Dee Estuary. Warrington is the largest settlement, and the city of Chester is the county town.