John P Green (UK)
The large working quarry at South Ferriby, North Lincolnshire (SE991204) is a well known and productive source of Late Jurassic and Cretaceous fossils, exposing beds from the Upper Oxfordian stage, Upper Jurassic (Ampthill clay, Ringsteadia psuedocordata zone) to the Terebratulina lata zone of the Turonian stage (Welton Chalk Formation, Upper Cretaceous). Research on the stratigraphy and palaeontology of the site has been carried out by many authors, and a generalised section detailing the overall stratigraphy and macrofossil occurrences was published by the local amateur geologist, Dr Felix Whitham (1992). However, in recent years, access to the quarry for geologists has been relatively curtailed due to health and safety concerns. In light of this, my research at South Ferriby has shifted to the nearby geological exposures on the easily accessible foreshore, on the southern banks of the Humber Estuary.
In general terms, the beds exposed on the South Ferriby foreshore tilt eastward, exposing the older (Jurassic) rocks to the west and the younger (Cretaceous) rocks to the east. The exposures are largely wave-cut platforms, accessible only at low tide, and are often covered with sand and estuarine sediments, as well as a large variety of erratic rocks and fossils. Especially prominent among the latter are carboniferous corals and limestones, Cretaceous flints, the Jurassic oyster, Gryphaea, and specimens of the Cretaceous (Late Campanian) belemnite, Belemnitella mucronata, most likely derived from chalk of this age that floors the North Sea. The low cliffs at the top of the beach consist largely of quaternary deposits and these are often overlain by waste material from former quarry workings located near the river. Due to the intermittent and transient nature of the exposures, a comprehensive review of the geological succession is not possible and descriptions are limited to the exposures currently accessible.
The Jurassic Ampthill Clay Formation has not been observed by me in the shore exposures. However, the belemnite, Pachyteuthis abbreviata, and specimens of the large bivalve, Gryphaea dilotata (both characteristic of this deposit) commonly occur in the beach debris to the extreme west of the outcrops, suggestive of the presence of small exposures that could possibly lie below water level. However, minor exposures of the overlying Kimmeridge Clay Formation are exposed and have yielded the oyster, Deltoideum delta, belemnites and small ammonites in concretions, possibly (and mainly) ?Rasenia sp. Co-occurring within these concretions is a rich bivalve fauna, notably Oxytoma expansum, pholadomya sp. and small oysters. Of particular interest is the record of a well-preserved dorsal fin spine of the hybodont shark, Asterocanthus sp.
The Carstone formation (Albian stage, Early Cretaceous) uncomfortably overlies the Kimmeridge Clay, but here, again, exposures are not present due to the overburden of sand and mud. However, at extreme low tide, the overlying Hunstanton Formation (Red Chalk, Albian stage) is exposed, which is a highly fossiliferous deposit yielding the brachiopods, Moutonithyris dutempleana and Platythyris capilatta, the small belemnite, Neohibolites minimus, and the inoceramid bivalve, Birostrina concentricus. Very rare fragmentary ammonites have also been recovered, although identification is hindered due to their poor preservation. Better preserved ammonites recorded from the Red Chalk at the South Ferriby quarry have been found, and these invite correlation with the Albian Gault Clay of Southern England.
The overlying white chalk (Upper Cretaceous) forms the majority of the exposures present. It is referred to as the Ferriby Chalk Formation, with the area under discussion representing the type locality (Wood and Smith, 1978). The succession as exposed at the nearby quarry is around 25m thick and extends from the erosion surface at the top of the Hunstanton Formation up to the erosion surface at the top of the Holaster trecensis zone of the Upper Cenomanian. A prominent clay layer, the so called “Black Band’’, overlies this erosion surface and represents the Cenomanian/Turonian stage boundary.
The basal chalk beds represent the lower Cenomanian stage, consisting of hard, thin bedded chalks, containing marl wisps and streaks, and belong to the zone of Holaster subglobosus. The lower beds are hard, platy chalks, extensively exposed on the rock platforms and yield abundant Inoceramus crippsi and related species, as well as common body whorls of the ammonite, Schloenbachia varians; very rare complete specimens can also be found. Of particular interest is the record of a single specimen of Scaphites equalis, a heteromorphic ammonite that is abundant in the corresponding Chalk Marl of Southern England, but which is very rarely recorded in the Northern Chalk Province. Other fossils present within these lower beds include rare brachiopods, the zonal echinoid, Holaster subglobosus, and very large body chambers of the ammonite, Hypoturrilites acutus.
Of additional note is the record of the echinoid, Hemiaster griepenkerli. Whitham (1991) described this rare echinoid from the quarry at South Ferriby and also from the quarry at Melton Bottoms (SE 973273) north of the Humber, and he considered it to exhibit similarities to Cenomanian forms previously described from Russia. This is one example demonstrating the faunal differences between the chalk of Southern England and that of the north, in that many faunal elements present in the north show affinities with those of Germany, Poland and Russia, rather than with Southern England, as would perhaps be expected.
Above the Schloenbachia beds are a sequence of relatively poorly fossiliferous chalks, about 5m thick, but minor shore exposures of a stratigraphically higher and prominent, 1m-thick bed of light grey, fossiliferous chalk – the Totternhoe Stone – have yielded abundant terebratulid brachiopods and echinoids, including Camerogalerus cylindrica and Holaster subglobosus. The top of the Totternhoe Stone has yielded large specimens of the ammonite, Parapuzosia (austiniceras) austeni, as well as a single specimen of the ammonite, Turrilites ?schuezerianus. If the latter identification is correct, it is of particular interest, in that this latter species has been rarely recorded in the Northern Chalk Province.
The overlying beds of chalk, about 8m thick, are poorly exposed on the foreshore and, where present, yield sporadic inoceramids and sparse echinoids, as well as fragments of large ammonites (Parapuzosia). The Black Band (a prominent layer of dark clay) at the top of these beds is not exposed, but is of interest in that it represents not only the Cenomanian/Turonian stage boundary, but also a major extinction event during mid-Cretaceous times. However, a more in-depth account of this horizon and its global implications lies beyond the scope of this article; further information can be found in Mitchell (1995) and Horne (1995).
The beds overlying the Black Band represent the Lower Turonian stage and belong to the Welton Chalk Formation. In the lower 2m to 3m, this consists of coarse, gritty, shell detrital chalks, characterised by abundant specimens of the inoceramid bivalve, Mytiloides Labiatus; the highest beds yield variants of this species. These beds have also yielded the small echinoid, Conulus subrotundus, and the brachiopods, Orbirhynchia sp. and Gibbithyris sp.
Within these inoceramid-rich beds, above the Black Band, I have also recovered the large ammonite, Lewesiceras Peramplum, and the very distinctive, spiny Mammites Nodosoides. This latter ammonite occurs together with Mytiloides Labiatus worldwide at this horizon and is therefore of great biostratigraphical significance. The beds above these shelly chalks, exposed on the shore and in loose debris, belong to the Terebratulina lata zone. These consist of hard, clean-looking chalk, with nodular and burrow form flints with marl bands and are very poorly fossiliferous, yielding only very sparse brachiopods (Gibbithyris semiglobosa) and sporadic inoceramid bivalves of the Brogniarti/Cuvieri/Lamarcki groups. The index fossil is very rare within this zone and, at the present locality, has yet to be observed by me.
The chalk dips below beach level further to the east, as one heads towards the Humber Bridge, and becomes obscured beneath both estuarine sediments and quaternary deposits, as well as the usual erratic rocks and fossils. However, it is of interest to note that many of these same erratics occur on the Humber coastline and on down the Lincolnshire coast towards the Wash. As noted previously, these erratic rocks and fossils, are of particular interest and indeed are worthy of a future article in their own right.
Horne, M.J. 1995. The Black Band Member.
Humberside Geologist 11, 40 – 41.
Mitchell, S.F. 1995. The Black Band at Speeton.
Humberside Geologist 11, 42 – 43.
Whitham, F. 1991. The Stratigraphy of the Upper Cretaceous Ferriby, Welton and Burnham Formations north of the Humber, north east England.
Proceedings of the Yorkshire Geological Society 48, 227 – 254.
Wood, C.J., and Smith, E.G., 1978. Lithostratigraphical Classification of the Chalk of North Yorkshire, Humberside and Lincolnshire, Proceedings of the Yorkshire Geological Society 42, 263 – 288.