The geology and history of Lyme Regis.


The Dorset coast is a very special place for its history of geology - so special in fact that it is being considered for World Heritage Site status along with the East Devon coast.

You can view this area from the coastal walks and boat trips from the Cobb.
Between Exmouth in Devon and Old Harry Rocks, Swanage in Dorset can be found one of the most complete sequences through the Triassic, Jurassic and Cretaceous periods of geological time anywhere in the world. The reason for this is simple, the overall dip of the rocks is gently to the east and this brings successively younger rocks to sea level along the coast with the oldest in the west and the youngest to the east.
The cliffs of West Dorset are formed from rocks of Lower Jurassic age and are capped by younger sandstone of Cretaceous age that give Golden Cap its cap.
Lyme Regis lies at the point where the Triassic rocks disappear below the sea and the oldest Jurassic rocks, thick clays and thin limestone of the 'Lias', form the cliffs. These rocks were deposited in a moderately deep tropical sea that was packed with marine life and as a result fossils are very common. Some, such as pencil shaped belemnites and coiled ammonites, are easy to find but others, like ichthyosaurs (marine reptiles) and fish are far rarer. The rocks also contain evidence of life on the land in the form of fossil wood, insects and even dinosaurs that were washed into the sea some 200 million years ago.

Giant landslides are active, especially during the wet winter months and cause huge mudflows to spill onto the beaches. The Black Ven Landslide, between Lyme Regis and Charmouth beaches is the site of the largest coastal mudflow in Europe that happened in the winter of 1958/9. The sea washes away the mud to leave countless fossils scattered in the sand.	The clay cliffs either side of Lyme Regis are formed from rocks of the Lower Jurassic age and are some 200 million years old. During the formation of the world, Lyme has been a desert as well as being deep under the sea.
A new species of Ichthyosaur found below Golden Cap in 1995. Despite over two hundred years of collecting, remains new to science continue to be discovered each year.	People have been collecting fossils for at least the last two hundred and fifty years, the most famous being Mary Anning who was born in Lyme in 1799. She extracted the first complete ichthyosaur, plesiosaur and the finest flying reptile among many other significant finds. But even today, collectors continue to make new discoveries; indeed one of the great attractions about collecting is that you never know what is out there waiting to be found.
Giant ammonites can be found on Monmouth Beach, just west of Lyme. They are far too large to extract and attempts to do so only lead to damage. They are best left where they are for all to enjoy and photograph.	The rocks around Lyme Regis and Charmouth are famous for fossilised remains such as this beautiful fish that lived in a tropical sea that once covered the area in the early Jurassic period.
If you do want to try your luck at collecting, there are some very important points to bear in mind. The best and safest time to collect is when the tide is going out. The tide floods the beach just east of Lyme shortly after low tide so always aim to pass this point around low tide. The cliffs are dangerous and prone to cliff falls at any time while the landslides contain treacherous mudflows so stay well clear. Anyway, the very best place to look is on the beach below the landslides. Monmouth Beach, just west of the famous harbour, the Cobb, contains huge ammonites. They are impossible to collect but if you cannot find any fossils elsewhere, at least you can take a picture of some home to show your friends. If you are still desperate to find fossils, come back in the depths of winter! The beaches around Lyme Regis are the best and safest places to search for fossils; the cliffs are not safe.
There are guided walks organised by the Charmouth Heritage Coast Centre, as well as the organisations mentioned below, and this is probably the way to get a head start.
Dinosaurland contains a large number of local specimens; the Philpot Museum has fossils and information about Mary Anning. Charmouth Heritage Coast Centre is very much a 'hands on' visitor centre with specimens, interactive displays and the 'Jurassic Theatre' with its audio-visual programme. The centre also manages a fossil collecting code of conduct and web site record of recent important discoveries. Several Fossil shops are to be found in Lyme and Charmouth. They contain both local fossils and geological specimens from around the world.