The Triassic and Jurassic Coasts

 

If you're going to Devon, one of the most prominent features that you're likely to want to explore is the famous Triassic coast which you can find along the Devon coast between Exmouth, Budleigh Salterton and Sidmouth.


Indeed, this contrasts with the Jurassic Coast of the Dorset world Heritage area here, on the Triassic coast, the geology records that the coast of Devon was a mixture of desert, sand dunes, rivers, with some interspersed sand dunes and salt lakes between 250 and 200 million years ago.

Devon Coast to Coast Routes From Sustrans

 http://www.sustrans.org.uk/ncn/map/route/devon-coast-to-coast

The spectacular colour of the cliffs on this area of the coast is due to the deposits of iron ore which are found in the minerals and rocks of the area a giveaway sign that apparently these rocks were formed on land in hot conditions.

However, there are different strata of rocks of to see in Devon for example, if you walk around the base of Orcombe Point, you'll find cross bedded sandstones these apparently were formed from sand grains in riverbeds due to the action of the flowing water. Geologist tell us that sand dunes in the nearby desert would be formed by sandwiches eroded from the riverbeds being blown out to form these dunes.

So Budleigh Salterton has one of the oldest and most historic elements in the world Heritage area the pebble beds, composed of hard quartzite, said to be 440 million-year-old rocks formed in a giant river flowing through the Triassic desert hundreds of millions of years ago.

Nowadays these pebbles are lodged loosely in the cliffs, and form much of the bulk of the beach at Budleigh Salterton. In fact, eroded by the salt water and waves, these rocks form much of the material on the beach which is unlike any other in southern England.

Of course one of the joys of the world Heritage site for both visitors and locals is the number of beaches which can be found in the area. You might have come across the phenomenon called "longshore drift" what this means, in effect, is that pebbles will move along the beach when waves strike the beach to certain angle.

Obviously the action of the waves on the pebbles can leave beautiful designs on the beach and you'll see this in the coast around Sidmouth.

But in addition, there's also a lot of geological exploration to be done in the area red rocks, with traces of greensand and white chalk, dominate your view, and strikingly obvious: it is part of the way in which the erosion of the world Heritage site Jurassic rocks has led to the exposure of the Triassic and Cretaceous substructure. And inland, the Hill's former plateau which rises to around 350 m again, a land surface over 40 million years old, produced by erosion in what must have then been a tropical climate.

So fascinating though all of this is, many people are more concerned with the attractions that exist today: picturesque fishing villages, the high cliffs of white chalk, which you can find a near Beer on the East Devon coast.

At Seaton, by comparison, read Triassic rocks can be seen dominating the shoreline.

Of course many of the rocks from this coastline in Devon have gained importance as building materials over the years: so just behind the village of Beer there's an intensely packed band of chalk which has been used as a building material since Roman times.

And of course where chalk is found, so is Flint so the chalk at Beer contains flint which has been used as a local building stone for generations in this area.

You have heard of the under cliff, perhaps at Lyme Regis, walking in the direction of Exmouth, because this part of the coast of Devon is truly famous not only for being a national nature reserve, but actually because of its unusual geological composition.

The whole area is actually formed from landslides and these still occur today, making this an extraordinary mix of habitats and offering a variety of flora and fauna all of which are interesting to the naturalist. English Bature, now known as Natural England, managed this reserve, and it's important that when you visit your bay the rules to protect the local flora and fauna

The original landslide which produced this unusual area known as the under cliff occurred at Bindone in 1839. Since then, the area has been colonised by woodland, and more recent heavy rain has produced smaller landslides nearer the village of Lyme.

Some of the most important and unusual fines fossils were the result of work by Mary Anning, who lived in the area in the 1800s she found the first icthyosaur and first complete plesiosaur found in Britain. Many of her fines are actually recognised as massively important through their display at the Natural History Museum.

So important is this area in terms of biological history, that it may not surprise you to learn that one species of dinosaur which has turned out to be completely unique to Lyme Regis and Charmouth has been found here.


Video - storms at Lyme Regis


You walk along the coast from West Dorset, Lyme Regis, to Burton Bradstock, you see one of the most spectacular coastal landscapes in England, including a hill known as Golden Gap although it's only 200 m or so high, is the highest cliff on the south coast of England. Devon Dorset are fortunate to have the South West Coast Path running through the region, although few walkers complete the entire path because of its extreme length, doubling back around the coast at lands end to traverse right up to North Devon as well.

But although this area is beautiful, it also presents a danger: coastal mudslides have occurred throughout history in this region, and they continue to occur today albeit on a smaller scale will stop both rockfalls and coastal mudslides have taken lives in the 20th and 21st centuries, and you are well advised to follow all warning signs if you decide to explore the beaches.

The Chesil Beach is also very well known location it's called a "barrier beach" and is made up of pebbles and shingles which has withstood the force of the Atlantic for apparently generation upon generation.

Behind it there is a beautiful tidal lagoon full of bird life, and despite the fact that the beach is 28 km long, and the pebble size increases from one end to the other, you can enjoy a difficult but exhilarating walk along its length.

That lagoon, behind the Chesil Beach is known as the fleet lagoon, and whilst it is preserved a mixture of fresh and brackish water species, there is a diverse mix of waterbirds and oceanic species such as seaweed and an enemies. Further down the road is the Abbotsbury's one very, which contains the world's largest managed swan population. There's another one at Bowness in the Lake District.

It's likely that you'll have heard of Portland stone, because many buildings in London were built from this fine white limestone. The most common and well-known example of Portland stone being used in building is in St Pauls Cathedral, the stone being chosen by Sir Christopher Wren because of its high quality and striking appearance.

Further along the coast, to the east of Weymouth, there's an interesting walking route which covers coastal section made up of a complex sequence of rocks mixed together by geological faults, consisting of Jurassic clays, limestones and sandstones. And interestingly enough, there's a natural rift in the seabed, caused by erosion, which has allowed oil naturally occurring underneath the seabed to escape and You Can Apparently Still See This Today near Brant Point.

Another famous place, slightly outside the Devon border, is Lulworth Cove and double door perfect coastal arches, which are famous both as a playground and as a beauty spot.