Geological Guide to Durlston

Marly Freshwater Bed

The top beds at Durlston are from the Purbeck, large boulders can be seen all over the foreshore. These are the Marble Beds and these dig at Peveril Point. At this point, the Broken Shell Limestone can often be seen on the foreshore. This is a hard, massive limestone with fragments of fish and turtles along with Neomiodon, Viviparus and Unio. This bed forms part of the Cypridea setina bed and continues at the Hotel Grosvenor. Below the Broken Shell Bed, the Middle Purbeck Chief Beds, there is approximately 8 meters of this bed, limestone's separated by shale. The first meter of this bed is full of gastropods of Promathildia, Hydrobia and Procerithium. The Scallop beds follow this.

Below the Chief and Scallop beds follows the Intermarine Beds, these are over 15m thick and include many limestone's and thinner alternating shale. The Shale yields fish and turtle remains. Below this, the Cinder bed forms the base of the Durlston Formation, full of oyster shells and bivalves. Below this, the Cherty Freshwater beds from the Lulworth formation yields many gastropods and beneath this the Marly Freshwater beds mark the location for the Mammal Bed. This freshwater bed which is 4m thick is full of gastropods of Valvata and Hydrobia, the mammal bed is in the middle of this section where turtle crocodile and fish remains can be found. Insects have also been recorded. The Soft Cockle Bed follows, there is some 22m of this bed with a large amount of Gypsum. The Hard cockle Bed follows, 4m of this, cockles here and tightly compacted.