Cox, B.M. & Sumbler, M.G. 2002. British Middle Jurassic Stratigraphy. Geological Conservation Review Series, No. 26, JNCC, Peterborough, ISBN 1 86107 479 4.
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B.M. Cox
Eastfield Quarry (now known as 'Everthorpe Quarry'), near South Cave in the East Riding of Yorkshire (formerly Humberside)
The following section is based on that recorded by G.D. Gaunt (BGS archives) during the 1:10 000 scale geological survey of the South Cave area in 1969–1971, with additional information, particularly of the beds above and below the Cave Oolite Member, from Sylvester-Bradley (1947), Bate (1967b), Brasier and Brasier (1978) and Gaunt et al. (1992). Bate's (1967b) section, with its extensive lists of ostracod species, is itself based on an unpublished detailed section recorded by Sylvester-Bradley in 1947. As with many sections, there is considerable variance between the different records but the so-called 'shell sands' allow some comparisons
| Thickness (m) | |
| Rutland Formation | |
| Thorncroft Sand Member | |
| Variegated sands and clays; limestone pebbles, shell fragments including occasional belemnites, pisoliths and ooids derived from underlying beds; base cuts down 1.8 m into underlying limestone to produce channel-like profile 8 m wide | seen to c. 1.2 |
| Lincolnshire Limestone Formation | |
| Cave Oolite Member | |
| Upper division | |
| Limestone, pale greyish-brown, pinkish and purplish in parts, massive, poorly sorted, ooidal, with abundant shell-debris and rare wood | 0.48 |
| 'Shell sand', pale yellowish-brown, partially cemented, ooidal | 0.25 |
| Limestone, well sorted, compacted, ooidal, with sporadic fine shell-debris at certain horizons; fine grained, pale greyish-brown, purplish at top and in lowest 0.05–0.10 m; medium-grained and cream-coloured in middle; in places, pale and grey-hearted; middle beds cross-bedded to east, north-east and south-east | 0.84 |
| 'Shell sand', pale-brown, unconsolidated | 0.06 |
| Limestone, pale greyish-brown, pinkish in parts, hard, thin-bedded, well sorted, compacted, very fine-grained, ooidal; thin, shell-debris rich parting near top | 0.28 |
| 'Shell sand', pale-brown, crumbly, with some white bands containing traces of ooidal structure | 0.01 |
| Limestone, pale grey-brown, pinkish in parts, hard, thin-bedded, well sorted, compacted, very fine-grained, ooidal | 0.58 |
| 'Shell sand', pale-brown, unconsolidated | 0.03 |
| Limestone, pale greyish-brown, slightly grey-hearted in middle and upper parts; well sorted, compacted, fine grained, with rare shell- and wood-debris in middle and upper parts; poorly sorted, medium-grained in lower part | 0.76 |
| 'Shell sand', partially cemented, slightly ooidal, with mottled rusty-brown concretionary patches and thin lenses of limestone | 0.25 |
| Limestone, pale greyish-brown; upper part pinkish and purplish, poorly sorted, compacted coarse oolite (pisolithic); lower parts partly grey-hearted, fine- to medium-grained with scattered fine to coarse (pisolithic) ooids, shell fragments and debris; two impersistent partings of 'shell sand' (up to 0.01 m thick) in middle part | 0.91 |
| 'Shell sand', pale-brown and slightly yellowish-orange, unconsolidated, with rare shell-fragments | 0.05 |
| Middle division | |
| Limestone, pale brownish-cream, grey-hearted in upper 0.3–0.45 m, medium sorted, compacted, fine to medium ooidal with rare shell-fragments; fairly massive but weathering into harder and softer bands and with thin impersistent lenses of unconsolidated 'shell sand' | 2.13 |
| Lower division | |
| Limestone, pale yellowish grey-brown mottled, grey-hearted in places, poorly sorted, fine to coarse (pisolithic) ooidal, with abundant shell-debris, sporadic larger fragments, rare whole shells and wood fragments | 0.56 |
| Limestone, pale greyish-cream, poorly sorted, fine to coarse (pisolithic) ooidal, with scattered shell-debris and rare whole shells 0.56 | |
| Limestone, pale yellowish-brown, soft, poorly sorted, fine to medium ooidal, with sporadic shell-debris; grey 'silty' limestones in lower part and thin grey mudstone beds, lenses and laminae in lowest 0.08 m | 0.33 |
| Kirton Cementstone Member | |
| Mudstone, pale-grey and brown, bedded and shaly in places, with rare, white, crumbly shell-fragments; upper 0.10 m contains sporadic thin beds and lenses containing white ooids, and is also slickensided; lower part contains rare ferruginous concretions | 0.41 |
| Limestone, pale-grey and brown mottled, with ferruginous 'earthy' ?silty and/or sandy appearance, and with sporadic shell-debris and ?ooids | seen 0.2 |
The majority of fossils found at Eastfield Quarry are bivalves, including Ceratomya bajociana (d'Orbigny), Gervillella scarburgensis (Paris), Lima, pectinids and Trigonia hemisphaerica Lycett, but the sandier partings often yield quite well-preserved specimens of the echinoid Pygaster semisulcatus (Phillips) (= Plesiechinus ornatus (J. Buckman)). Other echinoderms, in the form of pentacrinoid columnals, are abundant in some beds (Bate, 1967b). The bryozoan Collapora straminea (Phillips) and brachiopods (Acanthothiris) have also been recorded. Although fossils are relatively common, they are difficult to extract, except from the thin, soft, sandy partings between the limestone beds, and are usually fragmentary and poorly preserved (De Boer et al., 1958; Penny and Rawson, 1969). Brasier and Brasier (1978) recorded the trace fossils Arenicolites and Thalassinoides in the Cave Oolite Member as well as oyster-encrusted hard-grounds near its top.
Gaunt et al. (1992) believed that, for descriptive and correlative purposes, the Cave Oolite Member was best divided into lower, middle and upper parts (see above). At Eastfield Quarry, the lower part was referred to by the quarrymen as the 'Bottom Blue'. This is Unit B of De Boer et al. (1958) and probably beds 5–7 of Bate (1967b). The middle part comprises cross-bedded oolites with some pisoids, scattered shell-debris and a few wood fragments, and equates mainly with Unit C of De Boer et al. (1958) and beds 8–11 of Bate (1967b). The upper part of the Cave Oolite Member comprises mainly closely compacted, moderately to well-sorted oolites and contains shell debris especially in 'marly shell-sand' partings. In Eastfield Quarry, these oolites form the highest 4 m of limestone and exhibit low-angle cross-bedding dipping predominantly to the northeast (Gaunt et al., 1992).
According to Gaunt et al. (1992), close inspection of the apparently 'channelled' base of their Thorncroft Sand Member (= the lower arenaceous part of the Upper Estuarine Beds of previous authors) shows that the thin bedding, laminations and small-scale cross-bedded layers within that member are parallel to the junction with the Cave Oolite Member. From this, they deduced that these features are not part of a channel-fill but, having originally been deposited on a level surface, the beds have subsided into a hollow at the top of the Cave Oolite Member, presumably owing to solution of the limestone by acidic groundwater. Within the quarry, three large masses of Thorncroft Sand Member have been reported with their bases down to 3 m below the general top of the Cave Oolite Member, and Gaunt et al. (1992) suggested that these probably also occupy solution hollows. The Thorncroft Sand Member is now classified with the Rutland Formation, and is probably equivalent to the Stamford Member thereof (see
Although found loose, the specimen of Hyperlioceras
De Boer et al. (1958) reckoned that their units A and B could be compared with the upper part of the Lower Lincolnshire Limestone, and units C to I could be compared lithologically with the Upper Lincolnshire Limestone, and Gaunt et al. (1992) included the Cave Oolite as a member of that formation. The latter authors correlated it with the upper part of the Kirton Cementstone Member and the Hibaldstow Limestone Member of the succession south of the Humber (see Cliff House Pit GCR site report, this volume). They believed that the lower division (the so-called 'Bottom Blue') was the lateral equivalent of the Scawby Limestone (see Manton Stone Quarry GCR site report, this volume). Since they considered that the Cave Oolite Member was equivalent in part to the upper part of the Kirton Cementstone Member, above the Scawby Limestone, they queried the zonal implications of the Hyperlioceras found at Eastfield Quarry (see above), which conflicted with the zonal evidence of other rare ammonite specimens found south of the Humber (see
The relative stratigraphical position and the macrofaunal assemblage, including the bryozoan Collapora (formerly Millepora), have led to a correlation of the Cave Oolite Member with the unit known as the 'Millepore Bed' (Wright, 1860) on the Yorkshire coast (Clough-ton Formation, Lebberston Member) (see Chapter 5).
The fauna and lithologies are suggestive of deposition in a warm, shallow sea. Dune bed-forms suggest strong tidal conditions, the high-energy environment of which did not favour the preservation of ammonites.
The Eastfield Quarry site provides one of the last, and certainly the best, existing exposure of the Cave Oolite Member. It has also yielded the only known ammonite from that unit. It is a key site for establishing the correlation of the Cave Oolite Member with its lateral equivalents — the Lebberston Member of the Cloughton Formation in the Cleveland Basin, and the Kirton Cementstone and Hibaldstow Limestone members of the Lincolnshire Limestone Formation farther south into Lincolnshire.