Humberside Geologist no 2
published 1977
The cliffs immediately South of Bridlington, although grassed over are apparently composed of varved clays and as one proceeds down the coast these became better exposed, at first capped with a thin chalky gravel, well water-worn and then in places by a gravel of mixed erratics whose source is matter for speculation. Eventually the underlying Drab Till is exposed. Its upper few feet lack large erratics presumably indicative of gradual melting, one suspects, in water-logged conditions. The large melt-water lake must have stretched from round Skipsea northwards to Bridlington and was held up at its easterly side either by ice or a moraine which has long since been consumed by the encroachment of the sea.
Interesting bedding phenomenon in the clays are seen in various places and these near Barmston Drain were demonstrated to us by Mr C. Renn (in Journal of the Harker Geological Society, Spring 1975 for further details).
Peaty lake deposits are first seen some distance north of the Drain and continue to the south, the thickest deposit occurring just south of Skipsea village when it is several feet thick. Marly clays grade upwards into lake peats with numerous tree trunks and branches. Members were also able to extract acorns and hazel nuts. These deposits were studied many years ago in detail by Godwin (Antiquity, 7, 1933).
The remaining cliffs down to Hornsea are composed of Drab Clay the lower part of the cliff being typical compacted Boulder Clay with large erratics, although there is a thin peaty lake deposit near the top of the cliff just north of Atwick.
At the base of the cliff runs the "red-band" and also present are masses of squashed and smeared chalk. These features occur South of Hornsea and are also very evident at Dimlington. Near the highest point of the Atwick cliffs we encountered a very large erratic boulder (about 7' x 5' x 2') of crinoidal (Carboniferous) limestone, at the base of the cliff. The cliffs from Atwick down to Hornsea consist of Drab Clay only and the upper few feet exhibit a distinct weathering to a paler colour with a blueness in the vertical fissures resembling that in the "Hessle" Clay which caps the Purple Clay to the South of Hornsea showing convincingly that its distinction as a separate Till is an erroneous interpretation of a weathering phenomenon. Particularly, around Barmston the old wartime concrete blocks now resting on the beach measure for us the high rate of erosion - about a yard a year - which has taken place in the last 30 years.
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