Working out the stratigraphy of the various deposits in Holderness is not easy. The most obvious deposits are the Boulder Clays and here is a table comparing the names used by various authors.

There are other deposits and this is how they fit in to the stratigraphy:

The Geological Society (London) published "A revised correlation of Quaternary deposits in the British Isles" in 1999. In this various author applied modern stratigraphic principles (naming Formations, Members and Beds after stratotypes) to the British Quaternary. I am not sure that this has helped us to understand the Quaternary of East Yorkshire:- some of the names are confusing, one of the names has already been used for part of the Chalk, the bases are not defined, some type localities are vague and it is not clear which Formation the Dimlington Bed is in.

The new names introduced by S G Lewis are listed above and below are some more details.

The Fenland Formation - alluvium and peats from the "Fenland Basin".

Holderness Formation - consisting of seven Members and one Bed; type area is Holderness. These are listed here from the top down:

Flamborough Member - flat lying gravel truncating the top of the Skipsea Member. Stratotype somewhere on Flamborough Head. Should not be confused with the Flamborough Formation (Upper Cretaceous).

Hornsea Member - hummocky glacial deposits. Stratotype - East Holderness.

Withernsea Member - formerly the "Purple Till. Stratotype - Dimlington Cliff [TA376237].

Mill Hill Member - a shoestring body of gravel with diverse marine fauna, overlying Skipsea Member and eroded by Withernsea Member. Stratotype - Dimlington Cliff.

Skipsea Member - formerly the "Drab Till". Stratotype - Dimlington Cliff.

Dimlington Bed - laminated and rippled sand/silt containing Arctic moss remains preserved in hollows above the Bridlington Member. Stratotype - Dimlington Cliff.

Bridlington Member - formerly the "Basement Till", containing inclusions of Bridlington Crag - fossiliferous marine mud and glauconitic mud . Stratotype - Dimlington Cliff.

Sewerby Member - beach gravel, overlain by blown sand, colluvium and coombe rock. Stratotype - Sewerby [TA199686]. Should not be confused with the Sewerby Member (Upper Cretaceous).

Description of the sediments:

Basement Till - Dark grey-brown with erratics of small pieces of Chalk, flint, Magnesian Limestone, Carboniferous Limestone, Scottish and Scandinavian hard rocks (including Larvikite and Rhomb Porphyry), sandstones. Exposed between Kilnsea and Holmpton, also at Sewerby. Contains rafts of marine blue clays and glauconitic sands in places (-Bridlington Crag).

Skipsea Till - dark grey-brown. Contains more erratics of shale, siltstone and limestone than the Withernsea Till.

Withernsea Till - dark brown. Contains more erratics of Triassic, Liassic and Carboniferous age, plus Chalk and grey flint than the Skipsea Till.

References

Catt J 1987 in Ellis S 1987. East Yorkshire Field Guide. Quaternary Research Association, Cambridge.

Lewis SG 1999. Eastern England - chapter 2, p10-27 of Bowen D Q (ed.) A revised correlation of Quaternary deposits in the British Isles. Geological Society Special report no. 23. 176 pp.

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(c) Mike Horne + Hull Geological Society 1999 + 2007

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