Whitby Mudstone Formation


Lithostratigraphical position of the Staithes Sandstone Formation

Group Stage Formation Member
LIAS Toarcian Whitby Mudstone

Fox Cliff Sandstone

Peak Mudstone

Alum Shale

Mulgrave Shale

Grey Shale


This is a medium and dark grey fossiliferous mudstone and siltstone, laminated and bituminous in part, with thin siltstone and silty mudstone beds and rare fine-grained calcareous sandstone beds; dense, smooth argillaceous limestone nodules are very common at some horizons; phosphatic nodules at some levels. Nodular and fossiliferous limestones occur at the base in some areas.

In the Cleveland Basin around Staithes the base of the mudstone is resting upon the ooidal limestone or Sideritic nodules (Ironstone Doggers) of the Cleveland Ironstone Formation.