![]() At low tide boulders on the beach can be slippery and at high tide some parts of the exposures on the shore may be submerged. There have been major mudslides to the east of Black Head and wet deeply boggy patches may occur in these in which you could get stuck. In wet weather clay and other material may slump down the cliff. However, it is still possible and hard-hats should be worn. The moderate angle of the cliff here means that in dry weather, the risk of injury from falling debris is low. Of course, two knowledgeable sub-leaders would be needed for the two sub-groups. When visiting Osmington Mills with a large party of students on a general visit it can sometimes be useful to split the group with some proceeding east and others using this as an alternative locality. A useful student exercises can involve the graphic logging and measurement of parts of the Corallian sequence at both sites. Comparison of the upper part, however, can be made to the relevant section east of Osmington Mills (Bran Point etc). The lower part is in the reefs and most of it is not accessible. With regard to the Corallian (of the Upper Jurassic System), the Black Head section is most useful for the good exposures of the upper part. There are interesting aspects of coast erosion, mudsliding, fossils and sedimentology in this area, and if the various features en route are studied in detail, it may take an hour or more to reach the headland. There is a walk of about 30 minutes over the fallen Cretaceous and Kimmeridge boulders (fossiliferous and of interest) on the beach to reach the Corallian and Kimmeridge Clay cliff section at Black Head. It is easily reached by descending to the beach at Osmington Mills by the steps alongside the steep slipway and by turning right (westward) in the direction of Weymouth. It takes its name from the black or really, dark grey, Kimmeridge Clay which forms the upper, rather slumped, parts of the cliff. At one time it was probably larger and extended southward protected by a rampart of Corallian sandstones and limestones which have since been eroded to a series of low reefs. It is not at present a very prominant headland. Black Head (map reference SY 726819) is a cliff feature about a kilometre west of the Osmington Mills slipway. The photographs above show the location in relation to local features and to Osmington Mills, where there is a car park and pub (Smugglers Inn). Redcliff Point to the west will dealt with separately. It is specifically for the coast from Osmington Mills westward to Black Head and a short distance beyond (at Shortlake). This field guide is for a part of the "Jurassic Coast" World Heritage Site. Index to this Part of the Osmington Corallian Field Guide ![]() Osmington Mills - Geological Bibliography. | Osmington - Osmington Mills to Ringstead School of Ocean and Earth Science, Southampton University, Southampton Oceanography Centre Osmington Mills - Black Head: Geology of the Dorset Coast (part of the Jurassic Coast - World Heritage Site). Geology Field Guide - Osmington Mills - Pt.
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