Durlston Bay

If you are interested in microfossils, tiny mammal remains, turtle shell fragments, crocodile skin fragments and fish remains, Durlston Bay is ideal. It is also a good location to take samples for wet sieving. Don’t forget your field lens when visiting.

DIRECTIONS

♦ Take the A351 to Swanage. Stay on this road until you get to the seafront. Then, turn right into Shore Road and then into Institute Road. From this road, turn into Seymer Road and finally turn into Durlston Road. You will need to park down Belle Vue Road.
♦ Park in this road and take the footpath that is signposted as the ‘Zig-Zag’ path. This goes between the flats.
♦ The Zig-Zag path will take you to the shore, where you can immediately start looking for fossils.
♦ Ref: 50.60475°N, 1.95079°W

PROFILE INFO

FIND FREQUENCY: ♦♦♦♦ – Durlston does yield many fossils, but most of these are very small and are for the fossil enthusiast, rather than a beginner.
CHILDREN: ♦ – This location can have unpredictable tide conditions. Double tides frequently occur and the sea can be very powerful. The foreshore is also very rocky and access to the beach is difficult. Therefore, this location is not suitable for families with children.
ACCESS: ♦♦♦ – Access to this location is fairly easy, if you use the Zig-Zag path. This has now been re-opened after being closed as a result of a landslide.
TYPE: – Most fossils can be found on the foreshore, especially after storms, but they are also commonly found in the cliff. In particular, they can be found in the Mammal Bed, which is at the base of the cliff. Take home samples for analysing later.

FOSSIL HUNTING

This site is part of the Jurassic World Heritage Coastline, so please follow the Fossil Code of Conduct. This is also a SSSI, so no hammering of the cliff or bedrock is allowed. Damage has already been caused to the heritage site by people using power tools. This is strictly against SSSI rules and any attempt to ignore them may result in prosecution.

Within the dark banded freshwater Mammal Bed, fragments of bone are common, which are compacted within the soft black and grey layers. Fragments of crocodile, fish and turtle are very common, with other mammals also being found here. However, the bones are extremely fragile, so it is best to leave them within the shale and then extract and preserve them when home. An ideal way to collect here is to take several bags of samples home and wet sieve. Small teeth can also be found using this method, but make sure you sieve at 0.5mm, since many of the teeth will fall through anything wider than this mesh.

At the west side of Durlston Bay, the hard limestone rocks yield crocodile, turtle, mammal, fish and reptile remains and the occasional crustacean. Although less common than in the shales of the Freshwater Marly Bed, fossils in the limestone are much better preserved. They also tend to be less fragmented.

The beds are rich in microfossils, including some very rare small mammals, and also forams and ostracods. You can take back samples for sieving at home, but you will need a microscope and sieve with a 500 micron mesh.

Towards the middle of Durlston Bay, the Mammal Bed reaches the foreshore. This can be seen sandwiched between two hard limestone layers. There is then a thin black layer, followed by a grey layer, then a very thick second black layer and a lighter grey layer resting on top of the lower limestone.

Mammal remains can be found within the harder limestone, but these are rare. It is much easier to search through the shale. The Mammal Bed can easily be recognised by the colour and the number of freshwater shells in it. Note that the beds suddenly dip in the middle of Durlston Bay and run for a while along the foreshore. This is the point at which the Mammal Bed reaches the level of the beach.

To the west of Durlston Bay, mammal remains are more common within the hard limestone rocks on the foreshore. Sharks and fish remains can also be found, along with crustaceans and reptiles.

GEOLOGY

The 2 km stretch of coastal sea cliffs between Peveril Point and Durlston Head near Swanage, Dorset, displays the finest sections of the Purbeck Limestone Group in Britain and comprise the type locality for the Formation. The strata of the Purbeck Limestone Formation here are famous for their exceptionally diverse fauna, which includes mammal remains unique to the early Cretaceous of Britain and important reptilian material.

Durlston Bay represents a transition between the Jurassic and the Cretaceous periods. During this time, a large lagoon stretched along the coast; on the land were large numbers of dinosaurs and mammals, and in the shallow waters were crocodiles, sharks, fish and turtles. Both freshwater and marine forms of fish occur as fossils here, including abundant holostean material and teleost fishes. Durlston Bay is the type and only locality for two species of early teleost, Thrissops molossus and Pachythrissops laevis. It is also the type location for the coelacanth Holophagus purbeckensis.

The Purbeck Limestone Group has been split into two formal lithostratigraphical formations, the Durlston Formation above, and the lower, Lulworth Formation.

The Durlston Formation (previously Upper Purbeck Beds) succession is as follows:

Peverill Point Member

  1. Upper Cypris Clays and Shales: including the Marble Beds, largely composed of the freshwater gastropod, Viviparus.
  2. Unio Beds with the bivalve Unio
  3. Broken Shell Limestone (Soft Burr): a bioclastic limestone with fragmentary fish and turtle remains, along with the gastropods, Neomiodon and Viviparus, ,

Stair Hole Member

  1. Chief Beef Beds: Paper shales with Neomioden
  2. Corbula Beds: insects, fish, turtles and the bivalves Corbula and Protocardia
  3. Scallop Beds: thin beds yielding bivalves
  4. Intermarine Member (previously the Upper Building Stones): thin layer of bioclastic limestone with Viviparus, fish, turtles, amphibians, reptiles including lizards, turtles, crocodiles and dinosaurs and coprolites.
  5. Cinder Bed forms the base of the Durlston Formation, which is full of oyster shells and bivalves, including Praeexogyra distorta, Protocardia major, Laevitrigonia cineris and Nanogyra bulla. Spines and plates of the echinoid Hemicidaris purbeckensis.

 The Lulworth Formation (previously Lower Purbeck Beds)

Worbarrow Tout Member

  1. Cherty Freshwater Member: Limestones with chert, interbedded with mudstones and shales, with a diverse microvertebrate assemblage including gastropods, (Valvata and Hydrobia). fish, amphibians, reptiles and mammals
  2. Marly Freshwater Beds: Calcareous mudstones with a fauna of gastropods and ostracods. Included in the middle section is the Mammal Bed (‘Dirt Bed’): has yielded plant remains, mammal teeth and jaw fragments, turtles and crocodiles.
  3. Soft Cockle Bed: Micritic limestone, with the upper part consisting of mudstones and shales.. There is some 22m of this bed, which contains a large amount of gypsum. Insects are well known in this bed.
  4. Hard Cockle Bed: Calcareous shales totalling 4m thickness, in which cockles (mainly Protocardia) are tightly compacted.

Ridgeway and Mupe Members

  1. Cypris Freestones: Limestones interbedded with softer mudstones and clays. Ostracods and some insects. Marks the Jurasssic/Cretaceous boundary at Durlston Bay (i.e. the Tithonian/Berriasian boundatry)
  2. Broken Beds and Caps: mostly seen towards Durlston Head

Durlston Bay.jpg

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SAFETY

Common sense when collecting at all locations should be used and prior knowledge of tide times is essential. There are four tides a day here. Care should be especially taken at the two headlands. The sea nearly always reaches the cliffs and the rocks can be very slippery. Care should also be taken of falling rocks, as the cliffs are extremely unstable. Landslips are always possible here and the ground beneath your feet, if climbing the slopes, could give way at any time.

EQUIPMENT

There are two different rock types that fossils can be collected from – the dark shale and hard limestone. For that reason, it is best to take a range of tools, including hammers and, most essentially, a field lens. It is also worth taking some preserving liquid for fragile fossils.

ACCESS RIGHTS

This site is an SSSI and forms part of the UNESCO World Heritage Jurassic Coast. This means you can visit the site, but hammering the bedrock is not permitted. For full information about the reasons for the status of the site and restrictions please download the PDF from Natural England – SSSI Information – South Dorset

It is important to follow our ‘Code of Conduct’ when collecting fossils or visiting any site. Please also read our ‘Terms and Conditions

LINKS

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