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Photos from the Somerset coast (Lilstock to Shurton)

These are photos I took during a trip in early 2007. On this part of the coast most of the Penarth Group can be seen, as well as the base of the Blue Lias Formation. There's a lot of faulting, but this brings different parts of the succession to a level where the geology can be easily seen. As you walk east from the access at Lilstock the rocks get gradually younger, but due to the faulting this trend is frequently reversed locally. However, by the time you've walked the best part of the way to the power station you're well into the Lias. This first picture is of the oldest rocks exposed here: The Blue Anchor Formation. It's believed to have been deposited during a transition between sabkha, and shallow marine conditions.

The Blue Anchor formation

This is a rockfall from the base of the Blue Lias Formation. The Pre-planorbis beds are at the base of the Lias, and theses appear as the light brown flaggy rock in the top part of the cliff. If you look to the left you can see a light grey band that's the Cotham Member of the Lilstock Formation, and the black material below is the top of the Westbury Formation. The Westbury Formation is thought to have been deposited in marine conditions, though there is evidence of shallow water at some levels.

Westbury formation through to Blue Lias formation

An erosion surface between the top of the Westbury Formation, and underside of the Cotham Member of the Lilstock Formation. The Cotham member is a more calcareous deposit believed to be from a tidal flat environment.

Erosion surface

An annotated view of the succession.

Westbury formation through to Blue Lias formation

The top of the Langport member of the Lilstock Formation, and the base of the Pre-planorbis beds of the Blue Lias Formation. The Langport member shows evidence of a return to shallow marine conditions prior to the onset of fully marine deposition in the Lias.

Top of the Lilstock formation

2007