By Andy Tenny (neuropteris)

The Yorkshire Coast of England exposes a series of marine and terrestrial rocks ranging in age from the lower Jurassic at Cleveland in the north through to the chalk of the Upper Cretaceous at Flamborough Head in the South. Many of these formations are highly fossiliferous and yield a diverse range of fossils including marine reptiles, ammonites, belemnites, fish, nautiloids, bivalves and brachiopods, corals, crinoids, and in some of the terrestrial deposits, dinosaur foot prints and a wide range of plants. Even Pterosaurs have been found here. One of my favourite places for hunting is the beach at Ravenscar at the southern end of Robin Hoods Bay.


The Geology of Ravenscar

The rocks forming the cliff and rocky platforms exposed at low tide are of the Toarcian stage (the upper stage of the Lower Jurassic) dating from around 182 million years ago and comprise the following members of the Whitby Mudstone Formation (youngest to oldest) :-

Fox Cliff Siltstone (11m)

Peak Mudstone (13m)

Alum Shale (37m)

Mulgrave Shale (31m),

They are overlain by the gritty sandstones and pebble beds of the Dogger and Saltwick formations. The sequence represents a fairly deepwater basin (Mulgrave Shale) which became progressively shallower as time progressed (Alum Shale) until the area was finally filled with deltaic sediments brought in by the rivers running off an encroaching landmass to the north and west.

Collecting at Ravenscar

After parking at the lay by near the National Trust Center the way down to the beach leads through the...
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