Table 2.

Typical descriptions of geological units and corresponding slope morphology observed on the Broadway escarpment (adapted from Mott Macdonald Ltd 1992).

FormationDescriptionSurface morphology
Birdlip Limestone FormationOolitic and sandy ferruginous LIMESTONESteep scarp face (260 m OD) and Cotswolds plateau. Cambering and multiple rotational landslides.
Bridport Sand FormationFine to medium grained SANDSTONE.Cambering and landsliding.
Whitby Mudstone FormationDark grey CLAY with some oolitic LIMESTONEGentle angle slopes with remains of degraded rotational landslides.
Marlstone Rock FormationStrong brown closely jointed oolitic and fossiliferous LIMESTONE.Cap rock to midslope lithological bench (170–180 m OD).
Dryham FormationModerately weak orange brown SANDSTONE and SILTSTONE with subordinate bands of SILT and CLAY.Steep scarp faces below the lithological bench. Occasional large rotational landslides (Colliers Knap).
Charmouth Mudstone FormationDark grey CLAY with occasional bands of argillaceous limestone. Grades at depth into weak mudstone.Foot slopes and valley base. Mantled by superficial deposits and solifluction deposits.