This Earthcache is not available at high tide. Tides can be checked before your visit https://www.tidetimes.org.uk/watchet-tide-times

Fossil Beach, Helwell Bay, is a great place to find fossils and see the story of Watchet’s geology.

Watchet is very fortunate in its geology, lying on local lias rocks, set down 200 - 215 million years ago. When walking along Helwell Bay, you can easily imagine you are in another world as the ground under your feet can be littered with the remnants of the past. How and why have they been preserved here? 

If approaching from Watchet : follow the footpath from the railway crossing at Goviers Lane along behind the East Quay and up the steps. Take the coast path to Helwell Bay  cross the field and walk down the flight of concrete steps to the beach. 

You can also access the beach from Doniford Road ( trailhead start point N 51 10.732 W 003 18.481 which is closer but VERY limited parking)

From Watchet, the concrete steps down to the beach marks a major fault line, 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 to the older red mudstone. This can be seen most clearly by looking back at the steps as you walk along the beach.

The amazing find of a 200 million-year-old fossil dug up from Doniford beach almost 30 years ago and largely forgotten ever since, has now been hailed as one of the most important palaeontological finds for decades.

The Ichthyosaurus, found by an unknown beach-walker at Doniford in the mid-1990s, is not only the largest ever discovered but was found to be pregnant with a 7cm foetus – another scientific first.

After leaving West Somerset, the fossil eventually found its way into the collection of the Lower Saxony State Museum in Hannover.

It was put into store and remained unstudied for nearly two decades until palaeontologist Sven Sachs recently came across it by accident and realised it was “of absolutely massive importance”.

He contacted fossil expert Dean Lomax, of Manchester University, who confirmed that the reptile belonged to the species Ichthyosaurus Somersetensis, named after the county in which so many reptile fossils have been unearthed.

Mr Lomax said: “It amazes me that specimens such as this can still be ‘rediscovered ‘ in museum collections. You don’t necessarily have to go out into the field to make a new discovery. This specimen provides new insights into the size range of the species and records the only example of one with an embryo. This was still developing but has a backbone, fins, ribs and other bones.”

An excerpt from Watchet Scratch the Surface ( https://www.lovewatchet.co.uk/helwell-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 the 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 Helwell Bay."

Sounds a bit far fetched doesn't it Well, it's true!

A team from the University of Leicester and the Open University, working on a complex study of the red planet, have found that a type of rock found on Mars bears remarkable similarity to the geology of Watchet in West Somerset.

Mudstones found in the Gale Crater are close to the composition of rocks in Watchet and point to the likelihood of water once present on the planet.

The research, by Mars Science Laboratory Participating Scientists at The Open University and the University of Leicester, used the Mars Curiosity rover to explore Yellowknife Bay in Gale Crater on Mars, examining the mineralogy of veins that were paths for groundwater in mudstones.

The study suggests that the veins formed as the sediments from the ancient lake were buried, heated to about 50 degrees Celsius and corroded.

Professor John Bridges from the University of Leicester Department of Physics and Astronomy said: “The taste of this Martian groundwater would be rather unpleasant, with about 20 times the content of sulphate and sodium than bottled mineral water for instance!"

If you're interested in the research findings,more details can be found at www2.le.ac.uk/offices/press/press-releases/2016/august/veins-on-mars-were-formed-by-evaporating-ancient-lakes.

*** Edit by magwai : Marine reptiles, such as ichthyosaurs, and plesiosaurs are not dinosaurs but are often referred to as such. Marine reptiles ruled the waters whilst dinosaurs ruled the land. All marine reptiles could swim and lived in water. Dinosaurs, however, walked on land and had four legs, although some only walked on their hind legs.

Fossil hunting is one of life’s simple pleasures. There’s nothing quite like that feeling of holding a 200 million year old fossil in the palm of your hand and knowing it dates back to the age of the dinosaurs!

Collecting loose fossils from the foreshore is permitted in Watchet, but please never hammer at the rocks or cliffs as they are soft, fragile and the cliffs are very dangerous. There’s always an element of luck when fossil hunting, because it depends on what the last tide brought in, so a good time to come is after a high tide storm. Check tide times first.  Calmness and patience will help you get you ‘fossil eye’ in, so take your time, be slow and enjoy looking at all the treasures of the beach. 

Mudstone is a common sedimentary rock with a very fine-grained texture that it is sometimes called by various other names such as mudrock, argillite, claystone and siltstone. Shale is also a type of mudstone rock but differs from most other kinds of mudstones in that it is made up of visible layers. The geological process leading to mudstone formation begins when sediment like clay, mud and silt is deposited in areas such as lakes, the bottom of the ocean, or tidal zones. This material is then buried under more sediment and becomes lithified, meaning the fluids contained in it are removed while the remaining material is compacted under pressure. This type of rock looks like dried clay, and it comes in a wide variety of colours, including black, orange, white, gray, brown, and green.

Sedimentary rock is common in the outermost layer of the Earth's crust, and an estimated 65% of all sedimentary rock is mudstone. Mudstone is made up of very fine particles no larger than 0.0625 mm in diameter that can only be seen in a microscope. The color of mudstones is determined by its mineral content. Rocks containing iron oxide are commonly red, orange, or yellow, while rocks rich in pyrite or carbon are black

To claim this find, just answer these simple questions and send your answers to me using the Message Centre - Any logged find without answers after SEVEN DAYS will be deleted

1. Take a photo of the ammonite filled rocks at the posted co ordinates with something Geocaching related, it could be your GPS, pen, notepad, trackable or yourself!

2. At GZ, turn around and face the sea, you'll see the sheets of rock (they reminded me of huge sheets of crocodile skin) This is the hardened top of mudstone found in the area. Beneath that layer you will observe two more distinct layers.

Explain what you can see in the three layers of mudstone: 

Describe the variation in colour. What are the differences in particle size in the bottom, middle and top layers and why has this occurred? Describe the texture of these layers. Based on the colours you have observed in the layers, what do you believe the mineral content is ? 

3. Not compulsory and no additional brownie points but you may find it an interesting online search - The fossils in this area are around 201 million years old, what is the common name for this era?