Although it’s only about 25 minutes’ drive from my house, Branscombe is one of the few local beaches I’ve never visited. Today was a very low tide so I planned a trip with a friend. We were expecting to spend time rockpooling, but discretion was the better part of valour, since neither of us fancied breaking a leg amongst the seaweed-fringed boulders at the base of the beach. We weren’t disappointed though, as there is lots else to see.
Hooken Cliff to the east is the face of a jumbled undercliff that would send Victorian romantic poets and painters wild, calling to mind a monumental cathedral perched high up! It was formed by a large landslide in 1790, where the Cretaceous chalk and greensand (both marine deposits) slid down some 75m over the much older red Triassic Mercia mudstones that make up most of the cliffs to the west.
West of the nameless stream that flows across the pebbles, the full glory of the Trias is evident. These dark red rocks, which were laid down in desert conditions, are streaked, veined and bobbled with deposits of gypsum; some as massive milky blobs*, others as delicate salmon-pink sheets of brittle satin spar. Huge boulders have fallen from the cliffs so you can admire the patterns close to. The cliffs tower imposingly (into a blue sky the day I was there), topped by chalk or greensand.
(* Some of the white concretions I spotted look very like anhydrite nodules, which form in saline flats and lagoons by evaporation. Anhydrite is CaSO4 (calcium sulphate), and usually requires dry conditions to survive, hydrating to gypsum, CaSO4.2H2O, when weathered.)
The beach is littered with boulders like some natural sculpture park, each one waterworn or jaggedly fresh from the cliffs. Couple that with smooth golden sand sloping down to a sparkling sea, and you have the perfect venue for a beach walk, even if you aren’t interested in geology.
This section of the coast has yielded two useful products: the Beer Stone is a hard shelly limestone that was mined extensively inland at what’s now called Beer Quarry Caves, and used in building Exeter and Winchester Cathedrals amongst others; and gypsum which was, for a while, milled at the mouth of the river to make plaster.
As a geological aside, there’s a large bank of rock armour protecting a row of beach chalets at the foot of the red cliffs. Rather than the usual dour pile of black larvikite, this is a riotous jumble of granite, aplite, limestone, chalk and sandstone (and probably lots of others I didn’t spot). If we’re still around in a few million years, it will be a nice puzzle for the geologists of the future, since all but the chalk has come a long way from different locations! I probably give them more prominence here than they deserve, for purely decorative reasons.
PS If you decide to visit, don’t be put off by complaints online about being fined for overstaying in the car park. They’ve just installed a pay on exit system so you won’t be caught out.