THE GEOLOGY AND FAUNA OF THE SOUTH CAVE STATION QUARRY, Map No. O.S. 106 Grid Ref. SE 919330

By F. Whitham

In the past the division between the Middle and Upper Jurassic succession has been drawn at the junction of the lower and upper boundaries of the Cornbrash, lying stratigraphically below the beds of Kellaways strata and coinciding with the base of the English Callovian system.

More recently B. M. Cox in a Monograph of the Palaeontographical Society (1988), places the Kellaways beds within the Middle Jurassic sequence, based on the ammonite faunas. The Callovian strata includes three main lithostratigraphical units:- Upper Cornbrash, Kellaways Beds and Lower & Middle divisions of the Oxford Clay (see Fig. 1 Cox 1988). Reproduced below by kind permission of the author.

FIGURE 1

The outcrop of Kellaways Beds and Oxford Clay in the South Cave and South Newbald area of North Humberside consists of white and grey sandrock overlain by fine, soft micaceous sands with two rows of lime rich doggers about 1.5 metres below the top of the sandy beds. The sands above the doggers to the base of the rock formation, consist of several thin highly ferruginous bands. At South Newbald the doggers are much more massive than those found in South Cave Station Quarry, attaining a maximum size of approximately 2 metres in diameter and 1 metre in thickness. They consist of an intensely hard crystalline limestone and are usually packed with well preserved fossils - a sledge hammer is required to break open these concretions.

At the top of the ferruginous bands two conspicuous shell beds occur, the lower bed consists largely of many perfect specimens of the oyster Gryphaea bilobata along with numerous casts of bivalves, gastropods and ammonites, only in rare instances are the shells preserved in these beds. The large belemnite Cylindroteuthis puzosiana is also present in large numbers and very well preserved. The upper bed is more variable and in places grades into the base of the Kellaways Rock forming impersistent bands of almost black fairly hard rock packed with many species of bivalves and other fossils, in some instances with excellent shell preservation. Extremely hard patches of light coloured limestone occur in these black beds, in which, perfect specimens of ammonites (some of large size), bivalves, gastropods and brachiopods are to be found.

The succeeding beds of Kellaways Rock are approximately three metres thick and comprise of dark orange ferruginous sandstone varying in thickness and matrix, from locally consolidated sand and soft friable rotten stone to extremely hard limestone, with occasional very hard patches packed with numerous ammonites and nests of the ribbed brachiopod Rhynchonella socialis. The remainder of the rock formation yields an immense Callovian fauna in varying states of preservation. The top beds are highly crystalline and overlain by a band of eroded belemnites.

About two metres of Lower Oxford Clay overlies the belemnite bed and are said to belong to the Kosmoceras jason Zone, based on ammonites obtained from the lowest beds exposed in the Drewton Cutting during the construction of the railway in 1881. (de Boer, Neale & Penny 1958). More recently the writer has obtained examples of Gryphaea lituola, Pleuromya sp. the belemnites Cylindroteuthis puzosiana, Hibolites hastatus, and Legonobelus beaumontianes from these clays. In addition the sections of the Jurassic worm Hamulus vertibralis are also recorded.

Oxford Clay. Zone of Kosmoceras jason ? Middle Callovian

Gryphaea lituola

Pleuromya sp.

Cylindroteuthis puzosiana

Hibolites hastatus

Legonobelus beaumontianes

Hamulus vertibralis

Ammonite sp.

Kosmoceras jason ?

Kellaways Rock and Sands. Zone of Sigaloceras callovience

Cadoceras sublaeve J. Sowerby.

Cadoceras (Pseudocadoceras) ? laminatum Buckman.

Cadoceras (Pseudocadoceras) concinnum (Buckman)

Pseudocadoceras grewinki whithami geogr, subsp, nov. (Callomon)

Homoeoplanulites difficilis (Buckman)

*Choffatia recuperoi (Gemmellaro)

*Choffatia cardoti (Petitclerc)

Proplanulites sp.

Sigaloceras (Catasigaloceras) enodatum (Nikitin)

*Kosmoceras (Gulielmites) nodosum (Callomon)

*Kosmoceras (Gulielmites) medea (Callomon)

Kosmoceras (Gulielmiceras) gulielmi (J. Sowerby)

*Kosmoceras sub sp. anterior (Brinkman)

*Nautilus hexagonus

*Nautilus sp.

Cylindroteuthis puzosiana (d'Orbiny)

*Pachyteuthis semiredivia

Astarte duboise (d'Orbigny)

Astarte nummus (Savage)

Astarte multiformis (Roeder)

Astarte extensa (Phillips)

Anisocardia tenera (J. Sowerby)

Anisocardia sp. indef.

Anisocardia (Antiquicyprina) loweana (Morris & Lycett)

Arcomya unoniformis (Morris & Lycett)

Arca sp.

Copyright Hull Geological Society.