Hull Geological Society

Excursion to South Ferriby 9^th May 1970

Report

The object of the excursion was principally to study the succession of the Lower Chalk (Cenomanian) and obtain typical fossils of the North Lincolnshire Facies. There are now three large quarries in the “Cliff” between Barton and South Ferriby. The party first examined the exposure of the Lower Chalk on the foreshore below the most westerly of the three (in which the Turonian Middle Chalk only is exposed).  Here were found several loose ammonites which have yet to be identified, and a small in situ example of Schloenbachia which should be specifically identifiable and will be a useful indicator of the horizon.

After examining the large slabs of calcrete which form between the Boulder Clay and the Chalk, we went into the middle quarry, the larger of the two as listed as in South Ferriby. Here there is a great thickness of nearly barren Middle Chalk, but at the western side are some twenty feet of Lower Chalk and a good exposure of the Actinocamax plenus sub-zone. This belemnite, whilst widespread in Britain, is nowhere near common, and had been recorded only once from South Ferriby and once also from Melton Bottoms north of the Humber. Mr. B. Latham was fortunate to find a typical example, complete with the distinctive alveolar end but lacking its point. The sea-urchin Discoidea cylindrica was also found and a few small brachiopods, but none of the Ornatothyris which used to be obtainable in the quarry, often in clusters of a dozen or more. A small ammonite from a boulder of Middle Chalk may be identifiable as Pachydiscus.

On the return to the village the party looked at the spring which bubbles out onto the foreshore at the junction of the Chalk and the underlying clay a few hundred yards east of South Ferriby village. T. Sheppard, who was born in South Ferriby, said that these springs were known locally as ‘Chaddles’, a corruption of ‘St. Chad’s well’. There were traces of grey clay on the foreshore nearby among the shingle, which suggest the possibility of precise determination of the horizon of the clay below the Red Chalk at this point, about which there had been some doubt in the past.

In the afternoon the party went to the very large quarry worked by the Rugby Portland Cement Co. Ltd. for their South Ferriby plant. Here we found approximately 100 feet of Cenomanian Grey Chalk exposed up to the A. plenus Band and above that perhaps 200 feet of Turonian White Chalk (with flints). The collecting became brisker and there was a fair haul of identifiable ammonites, including a 3 foot Austeniceras, several Mantelliceras, an Acanthoceras and a Baculites. Lamellibranchs were common, especially Ostrea, Inoceramus and Spondulus; single examples of Camptonectes and Chlamys were also obtained. The typical echinoids were hard to find and were limited to Holaster ?subglobosus; but there was probably a new record for the North of England in a specimen of the little Discoidea subucula which is common at the same horizon in the south.

Potentially of great interest were the weathered contents of two twelve-inch bore-holes in the floor of the quarry which showed traces of Red Chalk, Carstone and the underlying clay. Macrofossils in the clay included small belemnites and serpulids. Samples were obtained for the study of the microfauna, and if this proves to be diagnostic of the horizon it will be a valuable additional record of the contact along the unconformity.

If not quite as comprehensive as the leader had hoped, the ‘bag’ was good and suggests that with such regular collecting in the vast exposures available the list can be extended greatly.

The following fossils have been sent to the Museum as the first contribution to the Society’s planned collecting scheme*.

*Editors’ notes –this was probably the plan to collect Chalk specimens for Hull Museum associated with the reprinting of 200 copies of the Wright brothers’ 1942 paper about “the Chalk of the Yorkshire Wolds” by Percy Gravett.   Also, the reader should be aware that the details of the stratigraphy and fossil nomenclature may have changed since 1970.

 [Transcribed by Mike Horne and edited by Paul Hildreth, June 2021]

copyright Hull Geological Society 2021