- Email: [email protected]
Palaeoecology of a reworked, Late Cretaceous inoceramid bivalve: Crimplesham, East Anglia, UK
G Model
PGEOLA-501; No. of Pages 4 Proceedings of the Geologists’ Association xxx (2016) xxx–xxx
Contents lists available at ScienceDirect
Proceedings of the Geologists’ Association journal homepage: www.elsevier.com/locate/pgeola
Palaeoecology of a reworked, Late Cretaceous inoceramid bivalve: Crimplesham, East Anglia, UK Nigel R. Larkin a, Stephen K. Donovan b,* a b
Cambridge University Museum of Zoology, Downing Street, Cambridge CB2 3EJ, UK Taxonomy and Systematics Group, Naturalis Biodiversity Center, Darwinweg 2, 2333 CR Leiden, The Netherlands
A R T I C L E I N F O
A B S T R A C T
Article history: Received 8 January 2016 Received in revised form 22 February 2016 Accepted 24 February 2016 Available online xxx
A flint erratic slab bearing a shell of the large inoceramid bivalve Volviceramus involutus (J. de C. Sowerby), with the valves oriented in a post-mortem ‘butterfly’ association, was collected from glacial float in an area of superficial deposits at Crimplesham, west Norfolk. This mollusc is typical of the Chalk and may be confined to the Coniacian. The shell is infested by encrusting oysters, Pycnodonte (Phygraea) vesiculare (Lamarck), and bryozoan borings, Foraripora pesavis Voigt and Soule. Infestation was most probably post-mortem. ß 2016 The Geologists’ Association. Published by Elsevier Ltd. All rights reserved.
Keywords: Taphonomy Norfolk Coniacian Volviceramus Pycnodonte Foraripora
1. Introduction Reworked fossils are part of the palaeontological record that may provide unexpected, even quirky data. For example, the Cretaceous rudistid bivalve Bournonia sanctmariae Chubb, 1967 (see Chubb, 1971, p. 195, pl. 40, fig. 13), was described from a single specimen reworked into and collected from the Eocene Richmond Formation of Jamaica; it remains unknown from any in situ occurrence. Glacial and fluvial erratics give the Netherlands a Palaeozoic palaeontology that it otherwise lacks in surface outcrop (such as Rhebergen, 2014; Donovan et al., 2016). Collecting Chalk erratics on Norfolk beaches can provide new insights into modern and ancient trace fossils or be a way to introduce children to palaeontology (Donovan and Lewis, 2010; Gee, 2013, p. 97). The most famous erratics in the British geological record were a forgery made to look like Pliocene relicts in Pleistocene gravels; we refer, of course, to Piltdown Man and its associated Crag fauna (Millar, 1972, p. 203; Donovan, 2015). Herein, we describe a Late Cretaceous fossil erratic of unusual size and completeness from which certain palaeoecological and taphonomic inferences are possible. Flints and cherts are among
* Corresponding author. Tel.: +31 71 568 7642. E-mail address: [email protected] (S.K. Donovan).
the most robust of clasts. In areas of chalk and adjacent regions, fossils in flint may be found in the overlying drift deposits (Donovan and Fearnhead, 2015), and cherts and flints may be transported by fluvial action for hundreds of kilometres (Donovan, 2010; Donovan et al., 2016). The glacial erratic described herein may not have been transported a great distance; its preservation is unusually fine, despite transport. 2. Locality and horizon Crimplesham Quarry (Frimstone Ltd. [The Dickerson Group], Main Road, Crimplesham, Downham Market, Norfolk, PE33 9ED) is located to the east of the village of Crimplesham in west Norfolk (Fig. 1; NGR TF 66267 03782). This is a large pit where aggregates are extracted; it is also used for landfill. The quarry contains a wide mixture of geological materials from a variety of ages from Holocene deposits, chalky till and large glacial erratics (including Cretaceous specimens) to Jurassic sedimentary rocks, comprising the Oxford Clay and Kimmeridgian Clay formations with ammonites and septarian nodules (www.crimplesham.ukfossils.co.uk; accessed 21 December 2015), examples of which can be found in the geology collection of Norwich Castle Museum. Other than the Holocene deposits, no well-defined strata are apparent in this pit due mainly to intensive glacial scouring and erosion. Cretaceous fossils are common, including belemnites, brachiopods, bivalves
http://dx.doi.org/10.1016/j.pgeola.2016.02.011 0016-7878/ß 2016 The Geologists’ Association. Published by Elsevier Ltd. All rights reserved.
Please cite this article in press as: Larkin, N.R., Donovan, S.K., Palaeoecology of a reworked, Late Cretaceous inoceramid bivalve: Crimplesham, East Anglia, UK. Proc. Geol. Assoc. (2016), http://dx.doi.org/10.1016/j.pgeola.2016.02.011
G Model
PGEOLA-501; No. of Pages 4 2
N.R. Larkin, S.K. Donovan / Proceedings of the Geologists’ Association xxx (2016) xxx–xxx
is now in the Natuurhistorisch Museum Maastricht, the Netherlands, registration number NHMM 2016 001. 3. Description
Fig. 1. Outline map of northern East Anglia, UK, showing the boundary of the county of Norfolk and the location of Crimplesham in relation to some of the major settlements. Inset map shows the position of the main map (=box) in the British Isles.
and sponges, but they are all glacially transported; no in situ Cretaceous stratum is exposed at Crimplesham Quarry. In a pile of disturbed material in the middle of this quarry, a well-preserved internal mould of the shell of the unusuallyshaped inoceramid bivalve Volviceramus involutus (J. de C. Sowerby, 1828) (Fig. 2) was found by the senior author in October 2004. Examples of this species preserved in flint with such fine detail are rare (but compare Fig. 2 with Cleevely and Morris, 2002, pl. 19, fig. 2). Further, this specimen preserved both valves in a ‘butterfly’ association (compare with, for example, Selover et al., 2005, fig. 3; Komatsu et al., 2007, p. 136; Skawina, 2013, fig. 2A) as well as an epifauna including boring bryozoans and a cementing bivalve mollusc. Although the specimen was not found in situ, the site manager confirmed that no material has ever been imported to the site. Therefore, until recently, it must have formed part of the glacially derived deposits within the quarry. The specimen was donated to Norwich Castle Museum and has the Accession Number NWHCM: 2006.627. A cast of the specimen
The two valves of V. involutus have very different shapes. The morphology of the coiled (left) valve (Fig. 2) in fact very much resembles a nautilid shell rather than a traditional inoceramid. Cobban (1983, p. 7) described this taxon thus: ‘‘V. involutus is a moderate-sized species that is inequilateral and extremely inequivalve. The left valve is much larger than the right valve, very inflated, spirally coiled, and nearly smooth. The right valve has a nearly oval outline and a very low convexity; it is ornamented with conspicuous concentric rugae’’ (Fig. 2; see also Cleevely and Morris, 2002, pp. 115, 117). The Crimplesham specimen, NWHCM 2006.627, corresponds to this description in all details and a new assessment of this species, based on a solitary shell, is considered unwarranted. The preservation of the shell is considered good because both valves are still in close association. Silicification has replaced both valves which are embedded in a flint nodule which weighs about 18 kg. However, the shell is crossed by cracks and pits (Fig. 3B) on the surface. These were the result of early biostratinomic mechanical damage, the products of the silicification process or both. On the right valve (lower in Fig. 2) cracks are essentially radial, whereas on the left valve they are radial but, because of the nautiloid-like shape of the shell, are sub-parallel and curve around the venter, away from the observer. The shell bears a fauna of episkeletozoans (sensu Taylor and Wilson, 2002) and borings which are worthy of further comment. The larger bivalve attached to the coiled left valve of the inoceramid (towards the right of this valve in Fig. 2) is possibly a juvenile of the pycnodonteine oyster, Pycnodonte (Phygraea) vesiculare (Larmarck) (pers. comm. to N.R.L. by Ireneusz Walaszczyk; see Cleevely and Morris, 2002, pp. 147–148, pl. 24, figs 8–10) (Fig. 3A). This has maximum dimensions of about 20 mm 20 mm and represents one valve, depressed on the surface of the inoceramid, presumably exposing the internal surface of the attached valve, although no muscle scar is apparent. At least one other specimen is present on the left valve, also showing the internal surface of the attached valve, but much smaller, about 4 mm 5 mm. The right valve appears to preserve a small free valve (presumably originally the whole episkeletozoan shell) with concentric growth lines, but preservation is poor (Fig. 3D). Other concentric surface markings may either be conspecific or are sports of the preservation or silicification process. The inoceramid also bears flint casts of ctenostome bryozoan borings, probably Foraripora pesavis Voigt and Soule, 1973 (Fig. 3C), previously described from the upper Campanian (Upper Cretaceous) of northern Germany (Paul D. Taylor, pers. comm. to N.R.L., 16 January 2008). This is the only species within this genus. These borings are infilled with silica, darker in colour than the inoceramid left valve except where both are obscured by strong staining and preserved flush with the shell surface. Borings are slender, crosscutting and twig-like, and are only apparent on the left valve, although the right valve has a uniform dark stain that would conceal any such trace. John W.M. Jagt (written comm. to S.K.D., 22 January 2016) has also identified a colony of cheilostome bryozoans, close to where both valves meet, on the cast NHMM 2016 001. 4. Discussion 4.1. Provenance
Fig. 2. Late Cretaceous inoceramid bivalve Volviceramus involutus (J. de C. Sowerby, 1828) from Crimplesham Quarry, west Norfolk (NWHCM 2006.627) with both valves clearly visible, left (upper, strongly curved) and right (lower right, more gently convex). The museum label towards the bottom of the specimen is about 30 mm in length. Specimen uncoated.
Volviceramus Stoliczka, most commonly V. involutus, is widely distributed. It is reported to occur in the Coniacian to Santonian of southern England and East Anglia (Cleevely and Morris, 2002,
Please cite this article in press as: Larkin, N.R., Donovan, S.K., Palaeoecology of a reworked, Late Cretaceous inoceramid bivalve: Crimplesham, East Anglia, UK. Proc. Geol. Assoc. (2016), http://dx.doi.org/10.1016/j.pgeola.2016.02.011
G Model
PGEOLA-501; No. of Pages 4 N.R. Larkin, S.K. Donovan / Proceedings of the Geologists’ Association xxx (2016) xxx–xxx
3
Fig. 3. Late Cretaceous inoceramid bivalve Volviceramus involutus (J. de C. Sowerby, 1828) from Crimplesham Quarry, west Norfolk (NWHCM 2006.627). Images show details of left valve apart from (D). (A) Inner surface of attached valve of the encrusting oyster Pycnodonte (Phygraea) vesiculare (Lamarck). (B) Detail of the curved edge of the left valve showing sub-radial cracks curving over the venter and small, circular pits, all probably post-mortem, but pre-silicification. (C) Bryozoan borings Foraripora pesavis Voigt and Soule, 1973. (D) Right valve, circular structures (*) assigned, uncertainly, to Pycnodonte (Ph.) vesiculare; alternately, they may be attachment scars of anomiid bivales. All scale bars represent 10 mm. Specimen uncoated.
p. 117), although other reports limit it to the Coniacian. For example, it is recorded from the lower to middle Coniacian chalk (e.g., Mortimore et al., 2001, fig. 3.124) including Lincolnshire and Yorkshire (Wilson, 1948, p. 69; Sumbler, 1999, p. 15), also France, the Czech Republic and as a middle Coniacian zone fossil in southern Poland (Remin, 2004), and the Coniacian of the Niobrara Formation of Colorado, Montana, Nebraska and North Dakota (Cobban, 1983, p. 7; Walaszczyk and Cobban, 2007), and New Jersey and New Mexico, USA. John Lord (pers. comm. to NRL, 22 May 2007) considered most of the flint found at Crimplesham Quarry, which is commonly bluish-white internally when broken, to be similar to cobbles found in Lincolnshire, in the vicinity of The Wold (near the Youth Hostel known as Woody’s Top). Here it was similarly ex situ, but had been moved there glacially. These blue-white flints took on iron staining from the gravels in which they are preserved at Crimplesham. They became both externally and internally a redbrown to cafe´-au-lait or parchment colour, with fine banding running throughout, commonly, but not invariably, parallel to the natural surface of the flint. Lord had never seen this sort of regularly banded flint in situ anywhere in the UK and thinks it may have been brought from off-shore or abroad to the area by ice movement; he had seen similar flint in Poland. A sedimentary unit found approximately 8 m below what appears to be the natural land surface at Crimplesham is comprised of sediment identical to that amongst which NWHCM 2006.627 was found, containing flints identical to the inoceramid in both size and colour, as well as both flints of smaller sizes and sand. Above this layer is a debris flow of similar, but finer-grained, material containing red sands, box-stones (=ferruginous concretions; Neuendorf et al., 2005, p. 80), some quartzite and vein quartz pebbles, and large orange flints. Cross-bedding is evident, moving south, overlain by about 6.5 m of fine-grained laminated sands and gravels.
4.2. Preservation Although it may be thought unlikely that such a well-preserved specimen V. involutus specimen should survive as a reworked fossil, Cleevely and Morris (2002) figured a second example. Both of these specimens are notable for preserving both valves of V. involutus in a ‘butterfly’ association. That is, fossilization occurred after the adductor muscle(s) had rotted away, but before the ligament linking the valves in the umbonal region had broken. To open the shell in such an orientation the shell was presumably on the sediment surface – not unexpected, as V. involutus was an epifaunal bivalve – and thus indicates the orientation of bedding within the flint slab. In this orientation the shell was buried and subsequently chertified. The shell of NWHCM 2006.627 has been replaced by flint. This is in contrast to, for example, the more commonly encountered flint steinkerns and external moulds of echinoids such as Echinocorys Leske (for example, see Donovan and Lewis, 2011). 4.3. Palaeoecology It is difficult to determine with full confidence whether the shell was infested by encrusting oysters and boring bryozoans before or after death. The butterfly condition of NWHCM 2006.627 indicates that V. involutus was only recently dead at the time of burial and might, therefore, suggest infestation was most likely pre-mortem. However, denser infestations of skeletobionts than these have accumulated post-mortem on all shell surfaces of some bivalves, both internal (after soft tissues had rotted) and external (Donovan et al., 2014). That there are borings and skeletobionts on the larger (left) valve, which would be the part of the shell expected to be in contact with the sediment surface in life, may be indicative of postmortem infestation. Unfortunately, the iron staining which coats
Please cite this article in press as: Larkin, N.R., Donovan, S.K., Palaeoecology of a reworked, Late Cretaceous inoceramid bivalve: Crimplesham, East Anglia, UK. Proc. Geol. Assoc. (2016), http://dx.doi.org/10.1016/j.pgeola.2016.02.011
G Model
PGEOLA-501; No. of Pages 4 N.R. Larkin, S.K. Donovan / Proceedings of the Geologists’ Association xxx (2016) xxx–xxx
4
much of the surface of the shell and the inability to examine the inner surfaces of the valves act together to preclude further, more informed assessment. 5. Conclusions A large shell of the Late Cretaceous (Coniacian?) inoceramid bivalve V. involutus (Sowerby) is preserved in a large slab of flint (c. 18 kg) recovered as a reworked fossil from superficial deposits at Crimplesham, west Norfolk, East Anglia, UK. The shell shows ‘butterfly’ preservation, and is infested by encrusting oysters, P. (Phygraea) vesiculare (Lamarck), and bryozoan borings, F. pesavis Voigt and Soule.
Acknowledgements N.L. thanks the following for their help and interest in this project: Ireneusz Walaszczyk (Institute of Geology, University of Warsaw); Paul D. Taylor (Natural History Museum, London); John W.M. Jagt (Natuurhistorisch Museum Maastricht); and the late Paul Whittlesea. Peter Hoare and John Lord are thanked for useful discussion about the provenance of the flints found at Crimplesham. The Dickerson Group and Frimstone Ltd. (owners of Crimplesham Quarry), and the staff on site, are thanked for their kindness in allowing access. We thank John Jagt and a second, anonymous reviewer for their considered comments. References Chubb, L.J., 1967. New rudist species from the Cretaceous rocks of Jamaica. Journal of the Geological Society of Jamaica 9, 24–31. Chubb, L.J., 1971. Rudists of Jamaica. Palaeontographica Americana 7 (45), 161–257. Cleevely, R.J., Morris, N.J., 2002. Introduction to molluscs and bivalves. In: Smith, A.B., Batten, D.J. (Eds.), Fossils of the Chalk, vol. 2. second ed. Palaeontological Association Field Guides to Fossils, pp. 99–160. Cobban, W.A., 1983. Molluscan Fossil Record from the Northeastern Part of the Upper Cretaceous Seaway, Western Interior. U.S. Geological Survey Professional Paper 1253-A, iv+52 pp. Donovan, S.K., 2010. A Derbyshire screwstone (Mississippian) from the beach at Overstrand, Norfolk, eastern England. In: Donovan, S.K., Van den Hoek Ostende, L.W. (Eds.), Palaeontological Papers in Honour of Dr. Cor F. Winkler Prins, Scripta Geologica Special Issue 7, pp. 43–52.
Donovan, S.K., 2015. A field guide to Charles Dawson’s discredited sites implicated in the Piltdown hoax. Proceedings of the Geologists’ Association 126, 599–607. Donovan, S.K., Cotton, L., Van den Ende, C., Scognamiglio, G., Zittersteijn, M., 2014. Taphonomic significance of a dense infestation of Ensis americanus (Binney) by Balanus crenatus Bruguie`re, North Sea. Palaios 28 (for 2013), 837–838. Donovan, S.K., Fearnhead, F.E., 2015. Exceptional fidelity of preservation in a reworked fossil, Chalk drift, South London, England. Geological Journal 50, 104–106. Donovan, S.K., Jagt, J.W.M., Deckers, M.J.M., 2016. Reworked crinoidal cherts and screwstones (Mississippian, Tournaisian/Visean) in the bedload of the River Maas, south-east Netherlands. Swiss Journal of Palaeontology 135,, 6 pp. Donovan, S.K., Lewis, D.N., 2010. Notes on a Chalk pebble from Overstrand: ancient and modern sponge borings meet on a Norfolk beach. Bulletin of the Geological Society of Norfolk 59 (for 2009), 3–9. Donovan, S.K., Lewis, D.N., 2011. Strange taphonomy: Late Cretaceous Echinocorys (Echinoidea) as a hard substrate in a modern shallow marine environment. Swiss Journal of Palaeontology 130, 43–51. Gee, H., 2013. The Accidental Species: Misunderstandings of Human Evolution. University of Chicago Press, Chicago xiii+203 pp. Komatsu, T., Huyen, D.T., Jinhua, C., 2007. Bivalve assemblages in north Vietnam and south China following the end-Permian crisis. New Mexico Museum of Natural History and Science Bulletin 41, 134–136. Millar, R., 1972. The Piltdown Men. St. Martin’s Press, New York 264 pp. Mortimore, R.N., Wood, C.J., Gallois, R.W., 2001. British Upper Cretaceous Stratigraphy. Geological Conservation Review. Joint Nature Conservation Committee, Peterborough 558 pp. Neuendorf, K.K.E., Mehl Jr., J.P., Jackson, J.A., 2005. Glossary of Geology, fifth ed. American Geological Institute, Alexandria, VA. Remin, Z., 2004. Biostratigraphy of the Santonian in the SW margin of the Holy Cross Mountains near Lipnik, a potential reference section for extra-Carpathian Poland. Acta Geologica Polonica 54, 587–596. Rhebergen, F., 2014. A new Late Ordovician erratic anthaspidellid sponge (Porifera) originating from Baltica. Scripta Geologica 146, 1–15. Selover, R.W., Gastaldo, R.A., Nelson, R.E., 2005. An estuarine assemblage from the Middle Devonian Trout Valley Formation of northern Maine. Palaios 20, 192–197. Skawina, A., 2013. Population dynamics and taphonomy of the Late Triassic (Carnian) freshwater bivalves from Krasiejo´w (Poland). Palaeogeography, Palaeoclimatology, Palaeoecology 379–380, 68–80. Sowerby, J. de C., 1826–1829. The Mineral Conchology of Great Britain, London, vol. 6. , 236 pp. Sumbler, M.G., 1999. The Stratigraphy of the Chalk Group in Yorkshire and Lincolnshire. British Geological Survey Onshore Geology Series, Technical report WA/99/02 30 pp. Taylor, P.D., Wilson, M.A., 2002. A new terminology for marine organisms inhabiting hard substrates. Palaios 17, 522–525. Voigt, E., Soule, J.D., 1973. Cretaceous burrowing bryozoans. Journal of Paleontology 47, 21–33. Walaszczyk, I., Cobban, W., 2007. Inoceramid fauna and biostratigraphy of the upper Middle Coniacian–lower Middle Santonian of the Pueblo Section (SE Colorado, US Western Interior). Cretaceous Research 28, 132–142. Wilson, V., 1948. British Regional Geology, East Yorkshire and Lincolnshire. HMSO, London iv+94 pp.
Please cite this article in press as: Larkin, N.R., Donovan, S.K., Palaeoecology of a reworked, Late Cretaceous inoceramid bivalve: Crimplesham, East Anglia, UK. Proc. Geol. Assoc. (2016), http://dx.doi.org/10.1016/j.pgeola.2016.02.011
PGEOLA-501; No. of Pages 4 Proceedings of the Geologists’ Association xxx (2016) xxx–xxx
Contents lists available at ScienceDirect
Proceedings of the Geologists’ Association journal homepage: www.elsevier.com/locate/pgeola
Palaeoecology of a reworked, Late Cretaceous inoceramid bivalve: Crimplesham, East Anglia, UK Nigel R. Larkin a, Stephen K. Donovan b,* a b
Cambridge University Museum of Zoology, Downing Street, Cambridge CB2 3EJ, UK Taxonomy and Systematics Group, Naturalis Biodiversity Center, Darwinweg 2, 2333 CR Leiden, The Netherlands
A R T I C L E I N F O
A B S T R A C T
Article history: Received 8 January 2016 Received in revised form 22 February 2016 Accepted 24 February 2016 Available online xxx
A flint erratic slab bearing a shell of the large inoceramid bivalve Volviceramus involutus (J. de C. Sowerby), with the valves oriented in a post-mortem ‘butterfly’ association, was collected from glacial float in an area of superficial deposits at Crimplesham, west Norfolk. This mollusc is typical of the Chalk and may be confined to the Coniacian. The shell is infested by encrusting oysters, Pycnodonte (Phygraea) vesiculare (Lamarck), and bryozoan borings, Foraripora pesavis Voigt and Soule. Infestation was most probably post-mortem. ß 2016 The Geologists’ Association. Published by Elsevier Ltd. All rights reserved.
Keywords: Taphonomy Norfolk Coniacian Volviceramus Pycnodonte Foraripora
1. Introduction Reworked fossils are part of the palaeontological record that may provide unexpected, even quirky data. For example, the Cretaceous rudistid bivalve Bournonia sanctmariae Chubb, 1967 (see Chubb, 1971, p. 195, pl. 40, fig. 13), was described from a single specimen reworked into and collected from the Eocene Richmond Formation of Jamaica; it remains unknown from any in situ occurrence. Glacial and fluvial erratics give the Netherlands a Palaeozoic palaeontology that it otherwise lacks in surface outcrop (such as Rhebergen, 2014; Donovan et al., 2016). Collecting Chalk erratics on Norfolk beaches can provide new insights into modern and ancient trace fossils or be a way to introduce children to palaeontology (Donovan and Lewis, 2010; Gee, 2013, p. 97). The most famous erratics in the British geological record were a forgery made to look like Pliocene relicts in Pleistocene gravels; we refer, of course, to Piltdown Man and its associated Crag fauna (Millar, 1972, p. 203; Donovan, 2015). Herein, we describe a Late Cretaceous fossil erratic of unusual size and completeness from which certain palaeoecological and taphonomic inferences are possible. Flints and cherts are among
* Corresponding author. Tel.: +31 71 568 7642. E-mail address: [email protected] (S.K. Donovan).
the most robust of clasts. In areas of chalk and adjacent regions, fossils in flint may be found in the overlying drift deposits (Donovan and Fearnhead, 2015), and cherts and flints may be transported by fluvial action for hundreds of kilometres (Donovan, 2010; Donovan et al., 2016). The glacial erratic described herein may not have been transported a great distance; its preservation is unusually fine, despite transport. 2. Locality and horizon Crimplesham Quarry (Frimstone Ltd. [The Dickerson Group], Main Road, Crimplesham, Downham Market, Norfolk, PE33 9ED) is located to the east of the village of Crimplesham in west Norfolk (Fig. 1; NGR TF 66267 03782). This is a large pit where aggregates are extracted; it is also used for landfill. The quarry contains a wide mixture of geological materials from a variety of ages from Holocene deposits, chalky till and large glacial erratics (including Cretaceous specimens) to Jurassic sedimentary rocks, comprising the Oxford Clay and Kimmeridgian Clay formations with ammonites and septarian nodules (www.crimplesham.ukfossils.co.uk; accessed 21 December 2015), examples of which can be found in the geology collection of Norwich Castle Museum. Other than the Holocene deposits, no well-defined strata are apparent in this pit due mainly to intensive glacial scouring and erosion. Cretaceous fossils are common, including belemnites, brachiopods, bivalves
http://dx.doi.org/10.1016/j.pgeola.2016.02.011 0016-7878/ß 2016 The Geologists’ Association. Published by Elsevier Ltd. All rights reserved.
Please cite this article in press as: Larkin, N.R., Donovan, S.K., Palaeoecology of a reworked, Late Cretaceous inoceramid bivalve: Crimplesham, East Anglia, UK. Proc. Geol. Assoc. (2016), http://dx.doi.org/10.1016/j.pgeola.2016.02.011
G Model
PGEOLA-501; No. of Pages 4 2
N.R. Larkin, S.K. Donovan / Proceedings of the Geologists’ Association xxx (2016) xxx–xxx
is now in the Natuurhistorisch Museum Maastricht, the Netherlands, registration number NHMM 2016 001. 3. Description
Fig. 1. Outline map of northern East Anglia, UK, showing the boundary of the county of Norfolk and the location of Crimplesham in relation to some of the major settlements. Inset map shows the position of the main map (=box) in the British Isles.
and sponges, but they are all glacially transported; no in situ Cretaceous stratum is exposed at Crimplesham Quarry. In a pile of disturbed material in the middle of this quarry, a well-preserved internal mould of the shell of the unusuallyshaped inoceramid bivalve Volviceramus involutus (J. de C. Sowerby, 1828) (Fig. 2) was found by the senior author in October 2004. Examples of this species preserved in flint with such fine detail are rare (but compare Fig. 2 with Cleevely and Morris, 2002, pl. 19, fig. 2). Further, this specimen preserved both valves in a ‘butterfly’ association (compare with, for example, Selover et al., 2005, fig. 3; Komatsu et al., 2007, p. 136; Skawina, 2013, fig. 2A) as well as an epifauna including boring bryozoans and a cementing bivalve mollusc. Although the specimen was not found in situ, the site manager confirmed that no material has ever been imported to the site. Therefore, until recently, it must have formed part of the glacially derived deposits within the quarry. The specimen was donated to Norwich Castle Museum and has the Accession Number NWHCM: 2006.627. A cast of the specimen
The two valves of V. involutus have very different shapes. The morphology of the coiled (left) valve (Fig. 2) in fact very much resembles a nautilid shell rather than a traditional inoceramid. Cobban (1983, p. 7) described this taxon thus: ‘‘V. involutus is a moderate-sized species that is inequilateral and extremely inequivalve. The left valve is much larger than the right valve, very inflated, spirally coiled, and nearly smooth. The right valve has a nearly oval outline and a very low convexity; it is ornamented with conspicuous concentric rugae’’ (Fig. 2; see also Cleevely and Morris, 2002, pp. 115, 117). The Crimplesham specimen, NWHCM 2006.627, corresponds to this description in all details and a new assessment of this species, based on a solitary shell, is considered unwarranted. The preservation of the shell is considered good because both valves are still in close association. Silicification has replaced both valves which are embedded in a flint nodule which weighs about 18 kg. However, the shell is crossed by cracks and pits (Fig. 3B) on the surface. These were the result of early biostratinomic mechanical damage, the products of the silicification process or both. On the right valve (lower in Fig. 2) cracks are essentially radial, whereas on the left valve they are radial but, because of the nautiloid-like shape of the shell, are sub-parallel and curve around the venter, away from the observer. The shell bears a fauna of episkeletozoans (sensu Taylor and Wilson, 2002) and borings which are worthy of further comment. The larger bivalve attached to the coiled left valve of the inoceramid (towards the right of this valve in Fig. 2) is possibly a juvenile of the pycnodonteine oyster, Pycnodonte (Phygraea) vesiculare (Larmarck) (pers. comm. to N.R.L. by Ireneusz Walaszczyk; see Cleevely and Morris, 2002, pp. 147–148, pl. 24, figs 8–10) (Fig. 3A). This has maximum dimensions of about 20 mm 20 mm and represents one valve, depressed on the surface of the inoceramid, presumably exposing the internal surface of the attached valve, although no muscle scar is apparent. At least one other specimen is present on the left valve, also showing the internal surface of the attached valve, but much smaller, about 4 mm 5 mm. The right valve appears to preserve a small free valve (presumably originally the whole episkeletozoan shell) with concentric growth lines, but preservation is poor (Fig. 3D). Other concentric surface markings may either be conspecific or are sports of the preservation or silicification process. The inoceramid also bears flint casts of ctenostome bryozoan borings, probably Foraripora pesavis Voigt and Soule, 1973 (Fig. 3C), previously described from the upper Campanian (Upper Cretaceous) of northern Germany (Paul D. Taylor, pers. comm. to N.R.L., 16 January 2008). This is the only species within this genus. These borings are infilled with silica, darker in colour than the inoceramid left valve except where both are obscured by strong staining and preserved flush with the shell surface. Borings are slender, crosscutting and twig-like, and are only apparent on the left valve, although the right valve has a uniform dark stain that would conceal any such trace. John W.M. Jagt (written comm. to S.K.D., 22 January 2016) has also identified a colony of cheilostome bryozoans, close to where both valves meet, on the cast NHMM 2016 001. 4. Discussion 4.1. Provenance
Fig. 2. Late Cretaceous inoceramid bivalve Volviceramus involutus (J. de C. Sowerby, 1828) from Crimplesham Quarry, west Norfolk (NWHCM 2006.627) with both valves clearly visible, left (upper, strongly curved) and right (lower right, more gently convex). The museum label towards the bottom of the specimen is about 30 mm in length. Specimen uncoated.
Volviceramus Stoliczka, most commonly V. involutus, is widely distributed. It is reported to occur in the Coniacian to Santonian of southern England and East Anglia (Cleevely and Morris, 2002,
Please cite this article in press as: Larkin, N.R., Donovan, S.K., Palaeoecology of a reworked, Late Cretaceous inoceramid bivalve: Crimplesham, East Anglia, UK. Proc. Geol. Assoc. (2016), http://dx.doi.org/10.1016/j.pgeola.2016.02.011
G Model
PGEOLA-501; No. of Pages 4 N.R. Larkin, S.K. Donovan / Proceedings of the Geologists’ Association xxx (2016) xxx–xxx
3
Fig. 3. Late Cretaceous inoceramid bivalve Volviceramus involutus (J. de C. Sowerby, 1828) from Crimplesham Quarry, west Norfolk (NWHCM 2006.627). Images show details of left valve apart from (D). (A) Inner surface of attached valve of the encrusting oyster Pycnodonte (Phygraea) vesiculare (Lamarck). (B) Detail of the curved edge of the left valve showing sub-radial cracks curving over the venter and small, circular pits, all probably post-mortem, but pre-silicification. (C) Bryozoan borings Foraripora pesavis Voigt and Soule, 1973. (D) Right valve, circular structures (*) assigned, uncertainly, to Pycnodonte (Ph.) vesiculare; alternately, they may be attachment scars of anomiid bivales. All scale bars represent 10 mm. Specimen uncoated.
p. 117), although other reports limit it to the Coniacian. For example, it is recorded from the lower to middle Coniacian chalk (e.g., Mortimore et al., 2001, fig. 3.124) including Lincolnshire and Yorkshire (Wilson, 1948, p. 69; Sumbler, 1999, p. 15), also France, the Czech Republic and as a middle Coniacian zone fossil in southern Poland (Remin, 2004), and the Coniacian of the Niobrara Formation of Colorado, Montana, Nebraska and North Dakota (Cobban, 1983, p. 7; Walaszczyk and Cobban, 2007), and New Jersey and New Mexico, USA. John Lord (pers. comm. to NRL, 22 May 2007) considered most of the flint found at Crimplesham Quarry, which is commonly bluish-white internally when broken, to be similar to cobbles found in Lincolnshire, in the vicinity of The Wold (near the Youth Hostel known as Woody’s Top). Here it was similarly ex situ, but had been moved there glacially. These blue-white flints took on iron staining from the gravels in which they are preserved at Crimplesham. They became both externally and internally a redbrown to cafe´-au-lait or parchment colour, with fine banding running throughout, commonly, but not invariably, parallel to the natural surface of the flint. Lord had never seen this sort of regularly banded flint in situ anywhere in the UK and thinks it may have been brought from off-shore or abroad to the area by ice movement; he had seen similar flint in Poland. A sedimentary unit found approximately 8 m below what appears to be the natural land surface at Crimplesham is comprised of sediment identical to that amongst which NWHCM 2006.627 was found, containing flints identical to the inoceramid in both size and colour, as well as both flints of smaller sizes and sand. Above this layer is a debris flow of similar, but finer-grained, material containing red sands, box-stones (=ferruginous concretions; Neuendorf et al., 2005, p. 80), some quartzite and vein quartz pebbles, and large orange flints. Cross-bedding is evident, moving south, overlain by about 6.5 m of fine-grained laminated sands and gravels.
4.2. Preservation Although it may be thought unlikely that such a well-preserved specimen V. involutus specimen should survive as a reworked fossil, Cleevely and Morris (2002) figured a second example. Both of these specimens are notable for preserving both valves of V. involutus in a ‘butterfly’ association. That is, fossilization occurred after the adductor muscle(s) had rotted away, but before the ligament linking the valves in the umbonal region had broken. To open the shell in such an orientation the shell was presumably on the sediment surface – not unexpected, as V. involutus was an epifaunal bivalve – and thus indicates the orientation of bedding within the flint slab. In this orientation the shell was buried and subsequently chertified. The shell of NWHCM 2006.627 has been replaced by flint. This is in contrast to, for example, the more commonly encountered flint steinkerns and external moulds of echinoids such as Echinocorys Leske (for example, see Donovan and Lewis, 2011). 4.3. Palaeoecology It is difficult to determine with full confidence whether the shell was infested by encrusting oysters and boring bryozoans before or after death. The butterfly condition of NWHCM 2006.627 indicates that V. involutus was only recently dead at the time of burial and might, therefore, suggest infestation was most likely pre-mortem. However, denser infestations of skeletobionts than these have accumulated post-mortem on all shell surfaces of some bivalves, both internal (after soft tissues had rotted) and external (Donovan et al., 2014). That there are borings and skeletobionts on the larger (left) valve, which would be the part of the shell expected to be in contact with the sediment surface in life, may be indicative of postmortem infestation. Unfortunately, the iron staining which coats
Please cite this article in press as: Larkin, N.R., Donovan, S.K., Palaeoecology of a reworked, Late Cretaceous inoceramid bivalve: Crimplesham, East Anglia, UK. Proc. Geol. Assoc. (2016), http://dx.doi.org/10.1016/j.pgeola.2016.02.011
G Model
PGEOLA-501; No. of Pages 4 N.R. Larkin, S.K. Donovan / Proceedings of the Geologists’ Association xxx (2016) xxx–xxx
4
much of the surface of the shell and the inability to examine the inner surfaces of the valves act together to preclude further, more informed assessment. 5. Conclusions A large shell of the Late Cretaceous (Coniacian?) inoceramid bivalve V. involutus (Sowerby) is preserved in a large slab of flint (c. 18 kg) recovered as a reworked fossil from superficial deposits at Crimplesham, west Norfolk, East Anglia, UK. The shell shows ‘butterfly’ preservation, and is infested by encrusting oysters, P. (Phygraea) vesiculare (Lamarck), and bryozoan borings, F. pesavis Voigt and Soule.
Acknowledgements N.L. thanks the following for their help and interest in this project: Ireneusz Walaszczyk (Institute of Geology, University of Warsaw); Paul D. Taylor (Natural History Museum, London); John W.M. Jagt (Natuurhistorisch Museum Maastricht); and the late Paul Whittlesea. Peter Hoare and John Lord are thanked for useful discussion about the provenance of the flints found at Crimplesham. The Dickerson Group and Frimstone Ltd. (owners of Crimplesham Quarry), and the staff on site, are thanked for their kindness in allowing access. We thank John Jagt and a second, anonymous reviewer for their considered comments. References Chubb, L.J., 1967. New rudist species from the Cretaceous rocks of Jamaica. Journal of the Geological Society of Jamaica 9, 24–31. Chubb, L.J., 1971. Rudists of Jamaica. Palaeontographica Americana 7 (45), 161–257. Cleevely, R.J., Morris, N.J., 2002. Introduction to molluscs and bivalves. In: Smith, A.B., Batten, D.J. (Eds.), Fossils of the Chalk, vol. 2. second ed. Palaeontological Association Field Guides to Fossils, pp. 99–160. Cobban, W.A., 1983. Molluscan Fossil Record from the Northeastern Part of the Upper Cretaceous Seaway, Western Interior. U.S. Geological Survey Professional Paper 1253-A, iv+52 pp. Donovan, S.K., 2010. A Derbyshire screwstone (Mississippian) from the beach at Overstrand, Norfolk, eastern England. In: Donovan, S.K., Van den Hoek Ostende, L.W. (Eds.), Palaeontological Papers in Honour of Dr. Cor F. Winkler Prins, Scripta Geologica Special Issue 7, pp. 43–52.
Donovan, S.K., 2015. A field guide to Charles Dawson’s discredited sites implicated in the Piltdown hoax. Proceedings of the Geologists’ Association 126, 599–607. Donovan, S.K., Cotton, L., Van den Ende, C., Scognamiglio, G., Zittersteijn, M., 2014. Taphonomic significance of a dense infestation of Ensis americanus (Binney) by Balanus crenatus Bruguie`re, North Sea. Palaios 28 (for 2013), 837–838. Donovan, S.K., Fearnhead, F.E., 2015. Exceptional fidelity of preservation in a reworked fossil, Chalk drift, South London, England. Geological Journal 50, 104–106. Donovan, S.K., Jagt, J.W.M., Deckers, M.J.M., 2016. Reworked crinoidal cherts and screwstones (Mississippian, Tournaisian/Visean) in the bedload of the River Maas, south-east Netherlands. Swiss Journal of Palaeontology 135,, 6 pp. Donovan, S.K., Lewis, D.N., 2010. Notes on a Chalk pebble from Overstrand: ancient and modern sponge borings meet on a Norfolk beach. Bulletin of the Geological Society of Norfolk 59 (for 2009), 3–9. Donovan, S.K., Lewis, D.N., 2011. Strange taphonomy: Late Cretaceous Echinocorys (Echinoidea) as a hard substrate in a modern shallow marine environment. Swiss Journal of Palaeontology 130, 43–51. Gee, H., 2013. The Accidental Species: Misunderstandings of Human Evolution. University of Chicago Press, Chicago xiii+203 pp. Komatsu, T., Huyen, D.T., Jinhua, C., 2007. Bivalve assemblages in north Vietnam and south China following the end-Permian crisis. New Mexico Museum of Natural History and Science Bulletin 41, 134–136. Millar, R., 1972. The Piltdown Men. St. Martin’s Press, New York 264 pp. Mortimore, R.N., Wood, C.J., Gallois, R.W., 2001. British Upper Cretaceous Stratigraphy. Geological Conservation Review. Joint Nature Conservation Committee, Peterborough 558 pp. Neuendorf, K.K.E., Mehl Jr., J.P., Jackson, J.A., 2005. Glossary of Geology, fifth ed. American Geological Institute, Alexandria, VA. Remin, Z., 2004. Biostratigraphy of the Santonian in the SW margin of the Holy Cross Mountains near Lipnik, a potential reference section for extra-Carpathian Poland. Acta Geologica Polonica 54, 587–596. Rhebergen, F., 2014. A new Late Ordovician erratic anthaspidellid sponge (Porifera) originating from Baltica. Scripta Geologica 146, 1–15. Selover, R.W., Gastaldo, R.A., Nelson, R.E., 2005. An estuarine assemblage from the Middle Devonian Trout Valley Formation of northern Maine. Palaios 20, 192–197. Skawina, A., 2013. Population dynamics and taphonomy of the Late Triassic (Carnian) freshwater bivalves from Krasiejo´w (Poland). Palaeogeography, Palaeoclimatology, Palaeoecology 379–380, 68–80. Sowerby, J. de C., 1826–1829. The Mineral Conchology of Great Britain, London, vol. 6. , 236 pp. Sumbler, M.G., 1999. The Stratigraphy of the Chalk Group in Yorkshire and Lincolnshire. British Geological Survey Onshore Geology Series, Technical report WA/99/02 30 pp. Taylor, P.D., Wilson, M.A., 2002. A new terminology for marine organisms inhabiting hard substrates. Palaios 17, 522–525. Voigt, E., Soule, J.D., 1973. Cretaceous burrowing bryozoans. Journal of Paleontology 47, 21–33. Walaszczyk, I., Cobban, W., 2007. Inoceramid fauna and biostratigraphy of the upper Middle Coniacian–lower Middle Santonian of the Pueblo Section (SE Colorado, US Western Interior). Cretaceous Research 28, 132–142. Wilson, V., 1948. British Regional Geology, East Yorkshire and Lincolnshire. HMSO, London iv+94 pp.
Please cite this article in press as: Larkin, N.R., Donovan, S.K., Palaeoecology of a reworked, Late Cretaceous inoceramid bivalve: Crimplesham, East Anglia, UK. Proc. Geol. Assoc. (2016), http://dx.doi.org/10.1016/j.pgeola.2016.02.011