Location: Lyme Regis
Rock type: Limestone and dark coloured mudrock
Age: Jurassic, 200 - 195 million years old
Look out for: fossils on the beaches.
Warning: Always follow the fossil collecting code
The geology in detail
The rocks in the cliffs at Lyme Regis represent layers from the oldest part of the Jurassic period and were layed down at the bottom of a deep sea between 200 and 195 million years ago. The shale layers that make up most of the cliffs East of Lyme are known as ‘black' shales because of their dark colour. The colour derives from the high amount of organic material included in the sediment. This tells us that the sea bed at the time must have been stagnant and had very little oxygen. Otherwise we would expect organic material of this kind to rot away and the shale to be a lighter grey colour.
The ancient environment
The nature of the rocks and the fossil contained within them points to a deep sea populated mostly by swimming creatures like ammonites, belemnites, fish, Ichthyosaurs and plesiosaurs. We know that this part of the world was much closer to the equator at the beginning of the Jurassic so it must have been a tropical sea. There were not very many creatures living on the sea bed because it was stagnant and they could not survive there.
Fossils
The important thing about having a stagnant sea bed is that it is a perfect environment to preserve the remains of creatures as fossils. Sometimes fossils from these layers are so well preserved that traces of the skin can still be seen! The quality of fossils and their abundance in these rocks means that the cliffs around Lyme Regis are recognised as the richest source of lower Jurassic giant marine reptiles, fish and insects.
Small fossils are constantly being washed from the soft cliffs by the sea. After a storm it can be quite easy to collect a handful of fossils from the beach including ‘fools gold' ammonites, belemnites, crinoids and even fragments of bone. Regular guided fossil hunting walks run from Lyme Regis Museum.
To the West of Lyme Regis there is a single layer of rock eroded into a wave cut platform that is covered in large ammonites. It is known as the ammonite graveyard or pavement and is a designated Special Site of Scientific Interest.Loading...
Orcombe Point - The beginning of the story
The western end of the World Heritage Site and the oldest rocks on the Jurassic Coast. Striking Red sandstones and mudstones can be seen in the cliff and the ‘geoneedle' on top of Orcombe point marks the start of the ‘walk through time'.
Budleigh Pebble Beds - Mountains and rivers
An incredible river deposit of pebbles from
across the channel and sandstones with ancient plant roots.
Ladram Bay - Sea stacks and the E.Devon AONB
Ladram Bay is a picturesque beach characterised by several
high sea stacks. It is one of the highlights of the East Devon Area of
Outstanding Natural Beauty (AONB)
Sidmouth - Desert dweller in the Otter Sandstone
Sidmouth is a traditional British seaside town bounded
within a wedge of red sandstone.
Beer - A story of stone Part 1
Beer is a picturesque fishing village and a source for
the famous Beer Stone.
Lyme Regis - World famous fossil site
Lyme Regis is famous worldwide for the abundant and
well preserved fossils that are found there eroded from the local cliffs.
Charmouth - World famous fossil site
Charmouth is famous worldwide for the abundant and
well preserved fossils that are found there eroded from the local cliffs.
Golden Cap - The highest view on the south coast
Golden Cap is the highest point on the south
coast and gives a fantastic viewpoint of this western part of the World
Heritage Site.
Chesil Beach - Finest barrier beach in Europe
Chesil Bank is one of the finest examples of a barrier
beach in Europe. Its formation is a direct
result of impact of the Ice ages on the geology and coastal processes of West Dorset.
Osmington Mills - Traces of life
Fantastic trace fossils can be seen on the beach at
Osmington Mills. Some of the best along the whole of the Jurassic Coast.
Durdle Door - The natural arch
Durdle Door, a huge natural rock arc, is an internationally
famous landmark and one of the most characteristic and spectacular features
along the Jurassic
Coast.
Lulworth Cove & Crumple - a geography pilgrimage
Lulworth Cove is a quintessential location for
the study of different rates of erosion in the formation of bays and headlands.
It is also a beautiful and popular tourist destination.
Old Harry Rocks - The end of the story
This is the eastern end of the Jurassic Coast
and where the youngest rocks on the world Heritage Site are exposed. Brilliant
white chalk has been eroded into steep cliffs and the famous collection of sea
stacks known as ‘Old Harry Rocks'.
Copyright 2011 Jurassic Coast