Geograph - photograph every grid square

Thanks to information from Mike Simms Link I now know that this bit of coast is the GSSP (Global Boundary Stratotype Section and Point) for the Sinemurian stage of the Early Jurassic epoch. A GSSP is an internationally agreed-upon stratigraphic section as arbitrated by the International Commission on Stratigraphy. In other words this coast at East Quantoxhead is the archetype with which to compare any other cliffs & rock formations for this particular geological period.
The Sinemurian stage commenced 196.5 (+/- 1) million years ago and lasted until 189.6 (+/- 1.5) million years ago. It is therefore very early in the Jurassic period, being the second stage of the 11 that make up the Jurassic. It is sandwiched between the Hettangian and the Pliensbachian stages. This latter stage's GSSP incidentally is at Robin Hood's Bay in Yorkshire (see NZ9505 : Low tide at Robin Hood's Bay).
The Sinemurian's defining marker is the first appearance of the Vermiceras and Metophioceras generas of ammonites. The characteristic spirals of ammonites are to be found in many of the rocks here and just up the coast at Kilve.