Fossil Beach, Helwell Bay, is a great place to find fossils and see the story of Watchet’s geology.
Grid ref: ST 076 434
From Harbour Road, take the footpath from the railway crossing along the quayside and up the steps to Splash Point. Follow the coast path to Helwell Bay car park. From the car park cross the field and walk down the flight of concrete steps to the beach.
The concrete steps down to the beach marks the line of a major fault, called the Watchet Fault. The red and green striped rocks on your left are Mercia Mudstones, dating from a time when the landmass was part of an ancient desert near the hot equator, similar to the Sahara today; on your right are grey mudstones belonging to the Helwell Marls. These marls are the youngest Jurassic rocks exposed on the Somerset coast and date from around 200 million years ago, when sea levels rose and Watchet was submerged in shallow seas. Here you will find some of the earliest ammonite fossils recorded in Britain. An ancient earthquake at this faultline pulled grey shale and mudstone down around 200m level to the older red mudstone. This can be seen most clearly by looking back at the steps as you walk along the beach.
Did you know?
- There’s oil in them there cliffs! In 1916 it was discovered that some of the dark bands of shales were bituminous (containing high quantities of organic matter) and oil-rich. The Shalime Company was set up and the ‘Somerset oil rush’ began. However it did not receive sufficient financial backing to make the venture successful. One brick oil retort still stands at the northern end of the car park at Kilve Pill a couple of miles down the coast.
- Scientists have concluded that rocks in craters on Mars are most similar to mudstone found in Watchet Bay. This points to the likelihood of there (once) being water on mars.
- Ancient sea dinosaur (technically marine reptile) fossil bones have been found on the Watchet coast. Watchet’s museum contains displays of local finds. Plesiosaurs, whose bones have been found, could grow up to 15m, roughly the length of the whole museum.
- The oldest ammonites in Britain are Psiloceras planorbis at 201 million years old. Their smooth, coiled shells along with their younger ancestors can be found preserved near the cliffs of Watchet’s Hellwell Bay.
- The diversity and local importance of geology in Watchet is commemorated in the Watchet Jubilee Geological Wall located on the railway station platform where local stone, minerals and fossils are displayed.