Lilstock Formation

Late Triassic (Rhaetian)

Lithology
Includes Cotham Member (grey and grey-green shales and siltstones) and Langport Member (porcellanous limestone below, calcareous mudstone above).

Upper Boundary
Placed at top of Langport Member, where there is a sharp but conformable junction with the overlying 'paper shale' of the "Blue Lias".

Lower Boundary
Placed at base of Cotham Member, sharp, commonly channeled on the Westbury Formation.

Representative Sites
Garden Cliff
Wainlode Cliff

Information on lithology and boundaries taken from the British Geological Survey Lexicon of Named Rock Units