Fossil worm burrows & scallops at Bran Point

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Trace fossils, also called ichnofossils, of tunnels and burrows made by small marine invertebrate creatures like crabs, million years ago in rocks at Bran Point, Ringstead Bay, Dorset, UK, on the Jurassic Coast (1) 

Incredibly, on the Jurassic Coast, which is famous for its fossils, you can  also see evidence of the way marine creatures lived – like the burrows and tunnels that they dug in the soft sediments long in the past. An example of this phenomena is the layer of Arenicolites worm burrows  buried in rocks from over 135 million years ago.

Fossils are usually formed from the hard parts of dead animals and plants. The parts could be the shells or bones of the animals. These become transformed through time into stone replicas of  the original structures. This happens most frequently through the action of minerals in the surrounding sediments gradually replacing, molecule by molecule, the  original components of the animal skeleton.

Fossils can also be formed when the original dead animal decomposes whilst at the same time leaving a perfect mould of its shape in the burial sediments. This mould can either remain hollow or eventually it may fill up with other percolating minerals or sediments; these harden to form a fossil that looks just like the original structure but is actually a cast of it – without any interior details and made of entirely different materials.

The Arenicolites beds at Ringstead are not the fossilised remains of the worms themselves by either of the two processes described above. They represent a third kind of preservation called trace fossilisation – that is, the preservation of evidence of the activities of the living animals such as the remains of burrows, tunnels, and tracks. Trace fossils are also known as ichnofossils.  The photographs in this post show preserved burrows and tunnels made by marine invertebrates like crabs and worms that can be seen in a section of rock jutting out from the base of the cliff nearest to Bran Point. [Bran Point marks the junction between the most western edge of Ringstead Bay and neighbouring Osmington Bay].  

Trace fossils, also called ichnofossils, of tunnels and burrows made by small marine invertebrate creatures like crabs millions of years ago, in rocks at Bran Point, Ringstead Bay, Dorset, UK, on the Jurassic Coast (2)

Fossil worm burrows: Trace fossils, also called ichnofossils, of tunnels and burrows made by marine worms millions of years ago, in the Arenicolites Beds in rocks at Bran Point, Ringstead Bay, Dorset, UK, on the Jurassic Coast (3)

Fossil worm burrows: Trace fossils, also called ichnofossils, of tunnels and burrows made by marine worms millions of years ago, in the Arenicolites Beds in rocks at Bran Point, Ringstead Bay, Dorset, UK, on the Jurassic Coast (4) 

Nearby to the worm burrow fossils are small fossil scallop shells (similar in appearance and size to the ones I have photographed at Studland Bay – see the posts of Sea shell from Studland & Scallop shells from Studland Beach) are embedded in the strata of the adjacent Bran Point ledge. These scallop shells give their name to this rock layer, the Chlamys qualicosta Bed.

Jurassic Coast fossils: Fossil scallop, Chlamys qualicostata, on the surface of rocks, surrounded by modern day growing acorn barnacles, at Bran Point, Ringstead Bay, Dorset, UK, on the Jurassic Coast (5)

Revision of a post first published 30 April 2009

COPYRIGHT JESSICA WINDER 2011

All Rights Reserved

5 Replies to “Fossil worm burrows & scallops at Bran Point”

  1. We have a beautiful fossil here on the ranch. Can anyone help us identify it?
    Can’t Cut and Paste here – write me if you are interested.

    Like

  2. Hello, Henry
    If you would like to send a picture of your beautiful fossil to winderjssc@aol.com, I will see if I can tell what sort of fossil it is – but I don’t think I will be able to give you a specific name – you would probably need a local expert for that.

    Like

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