Dorset and East Devon Coast World Heritage Monitoring

GCR Site: 794 Charmouth

Interest: Lower Lias Insects

GCR Block: Palaeoentomology

SSSI: West Dorset Coast

Site Boundaries: Grid Reference 335900, 93100 - 349600, 89200

Date of Assessment: Trial

Date of last assessment: N/A

Surveyor (s): Richard Edmonds

Statement of Significance:

The Woodstones and Flatstones at Black Ven and Stonebarrow are the most productive source of Lias insects in Britain. Five species unique to the site have already been described; many specimens collected have yet to be studied or described. The fauna includes representatives of the Odonata, Hemiptera, Coleoptera and Orthoptera, associated with a normal Lias Marine fauna. This derived but well-preserved insect fauna constitutes the richest accumulation known from the British Lower Jurassic.

Physical description:

The Woodstones and Flatstones are layers of round limestone nodules within the Black Ven Marls. Within the cliffs of Black Ven, the nodules, for the most part, lie within a bench that is largely obscured under slipped materials. At times, large numbers of nodules can be contained in ex situ landslipped blocks where the strata are still largely in sequence, and in mudslides. Along Stonebarrow only the flatstones are found (apart from a few woodstones at the western end of the cliff) and they are exposed in a vertical or near vertical cliff face before descending to sea level at the eastern end of their outcrop.

Health and Safety:

The cliffs contain deep and dangerous mudflows, especially during or after wet weather. The mudflows may spill onto the beach and can prevent access or exacerbate the risk of becoming cut off by the rising tide. Cliff falls are a further hazard and cliff falls can occur at any time. The incoming tide floods the beach below the old sea wall just east of Lyme Regis shortly after low tide and it is possible to become cut off here. Always aim to pass this point around low tide and beware, especially in rough weather. The beaches are often rough and boulder strewn. Green weed from the middle shore downward can make the boulders highly slippery.

Access:

The foreshore car park at Charmouth provides access to both Black Ven and Stonebarrow

Conservation Objectives, on site:

Key Scientific Important Specimens are recovered That the flatstones and woodstones and other nodule horizons are accessible in situ for scientific study as natural conditions allow

Conservation Objectives, off site:

Key scientifically important specimens are accessible to the scientific community Key scientifically important specimens are placed in registered museums

Success indicators:

Number of key scientifically important specimens (KSIS) recorded recorded specimens: 4 Number of specimens entering museum collections: 0 A further 34 specimens have been donated to the Natural History Museum (November 2003) including a number of KSIS to be registered Flatstone nodules accessible in situ: See GCR 87 Lower Lias Stratigraphy Woodstones are generally obscured by slipped material

Fixed Point photography:

See GCR 87

Scientific publications and ongoing research:

The Palaeontological Association 'Guide to the Fossils of the Lower Lias' is due to be published in spring 2004 Otherwise unknown

Natural Change:

Over the last 10 years the yield of nodules from the landslides, particularly at Black Ven, have greatly reduced in numbers due to erosion of the 1958/9 landslide (the principal ex-situ source).

Man made change:

The West Dorset Fossil Collecting Code of Conduct has brought about a reduction of digging in situ along the principal fossil bearing horizons.

ENSIS unit summary:

Unit 6 Favourable

Unit 8 Favourable

Unit 9 Favourable

Unit 10 Favourable

Comments:

Collecting effort is high in regard to these fossiliferous nodules (mostly for the ammonite fauna) and limited digging continues in the cliff. However, all horizons are accessible or can be readily made accessible. The resource is infinite

Other comments:

One criticism is that more insects should have been recorded than have been A second comment has been that the flatstone bed is better accessible than has been in the past

Sensitivity: High

Recommended survey period:

Ongoing through West Dorset fossil code of conduct

Overall Assessment:

Favourable

Actions:

Investigate inclusion of topstone and intermediate nodules within the GCR Promote collection of topstone and intermediate nodule insect faunas More effort should be made to encourage collection of all insect remains and greater communication should be encouraged between experts/researchers and collectors (appears now to be starting through a new contact Andrew Ross at the Natural History Museum).

Related GCR Blocks:

GCR 87 Pinhay Bay to Fault Corner Lower Jurassic Stratigraphy CGR 916 Lyme Regis Jurassic Reptilia GCR 2952 Lyme Regis Fish GCR 1321 Black Ven Mass Movement GCR 2109 Golden Cap - Lyme Regis Coastal Geomorphology of England

Comments and discussion

The Natural History Museum have just received numerous insect specimens from a local collector. 26/11/03 Chris Pamplin.