The type section of the junction of the Otter Sandstone Formation and the Mercia Mudstone Group (mid Triassic) at Pennington Point, Sidmouth

An almost complete section through the Otter Sandstone Formation and the Mercia Mudstone Group is exposed in the cliffs between Budleigh Salterton and Axmouth on the south Devon coast. This is the most complete succession at this stratigraphical level in Britain and has been proposed as the type section for the formation and the group. The conformable junction of the Otter Sandstone Formation and the overlying Mercia Mudstone Group (Sidmouth Mudstone Formation) is wholly exposed in the cliffs at Pennington Point, Sidmouth over a distance of 250 m. The shingle beach that fronts this section of cliff is subject to seasonal variations in thickness of up to 5 m. The cliff and foreshore sections are continually refreshed by wave action at times of low beach level. They expose about 15 m of interbedded sandstone and mudstone, for which the new name Pennington Point Member of the Otter Sandstone Formation is proposed, overlain by the uniform mudstones of the Mercia Mudstone Group. The member marks the transition from the predominantly fluviatile environments of the Otter Sandstone Formation to the arid environments of the Mercia Mudstone Group. Concentrations of fossil material in winnowed deposits in the Pennington Point Member at Pennington Point have yielded a more diverse assemblage of vertebrate fossils than at any other Triassic locality in Devon. This includes genera previously known only from Russia and central Europe, and the type material for two new species. The section is nationally important for correlation at this stratigraphical level and internationally important for magnetostratigraphical comparison with sections in southern Europe.