89 field meetings

The Weald Clay of the Weald: report of 1988/89 Field Meetings E. A. Jarzembowski JAR~EMBOWSKI, E. Meetm~s . Proc. Geol.

A. 1991. The Weald Clay of the Weald : report of 1988/89 Field Ass. , 102(2), 83-92 . The Lower Cretaceous geology (Hauterivian/ Barremian) of the Auc\aye , Clockhouse and Smokejacks Brickworks is described with special reference to recent fieldwork by the Geologists ' Associat ion .

Booth Museum of Natural History , Dyke Road, Brighton , BNl5AA

1. INTRODUCTION

The Weald Clay Group consists mainly of soft grey mudstone s, silty mudstones and siltstones weathering to mott~ed yellow a.nd brown, or locally red, silty clays. LIke other major Wealden mudstone units, the Weald Clay is interpreted as representing coastal lake lagoon , bay and river palaeoenvironments (Allen: 1990 and references). The Group is considered to be of ~arly Cretaceous: Hauterivian-Barremian (-early Aptian") age (loc. cit.) and has yielded the remains of rept!les.' fishes, molluscs, arthropods , plants, traces, Echm?l~ea ~nd Fo~aminifera; a Palaeontological ASSOCIatIOn FIeld GUIde to Fossils is currently being prepared. In the Weald sub-basin (i.e . south-east England ), the Weald Clay has a skewed -horseshoeshaped outcrop, surrounding the High Weald (Hastings Bed s Group) in Kent , Surrey, West and East Sussex .(British Geological Survey , 1964). The Weald Clay IS well developed in the Horsham area being some 330 m (1100 ft) thick (Gallois, Thurrell: Worssam & Bristow, 1972) and may be subdivided using sandstone or limestone beds which occur at intervals (Worssam, 1978). The Clay is dug commercially for making bricks and the fieldtrips were to three pits (national grid reference s in brackets) to the north-east of Horsham close to the Surrey/Sussex border: the Auclaye (TQ 170388), Clockhouse (Clock House/Butterley; TQ 175385) and Smokejacks (TQ 115372) Brickwork~ of ~hich the first pit is disused. The stratigraphical details and finds at the three pits are given below. Half a day was spent at each site and the car park on the north side of the entrance to the C1ockhouse Brickworks formed a convenient assembly point. For those without packed lunches, refreshment was found at 'The Crown '. i.n the nearby village of Capel. The dates of the VISItS (and numbers attending) were : 1988: 1 May (about 30), 12 June (97), 9 October (33), 1989: 18 June (over 51) of which the first was an informal meeting, and the last organised jointly with the geology section of the West London Wildlife Group . 2, AUCLAYE BRICKWORKS The disused pit is in the upper part of the mudstone interval between British Geological Survey bed nos. 83

3a & 3c (Gallais et al., 1972) that is, between the Okehurst and Billingshurst Sands (Allen, 1976) in the Lower Weald Clay of Hauterivian age (Allen, 1990). The pit formerly worked 9-12 m of grey , laminated 'clay' with layers of siltstone and brief sections are given by Worssam (1978) and Kirkaldy & Bull (1948). Fossils occur mainly in phosphatic concretions (Taylor, ~991) not iron carbonate (Jarzembowski, 1987) which are brown externally with blue-grey centres and which yield various insect fossils, some small plant matter including charcoal (fusain) and wood, occasional fish scales, bones and egg cases (p. 88), coprolites and isopod ('sea-slater') remains . Carapaces of a conchostracan (clam shrimp-misidentified previously in Worssam (1978) as Cyzicus (Lioestheria) subquadratus ) are locally abundant whilst lamellibranchs and ostracods are very rare. The site has been popularly dubbed the 'dragonfly pit' following the discovery of a well-preserved hawker dragonfly, Valdaeshna surreyensis, in a concretion in 1986 (Jarzembowski, 1988). In addition to Odonata from wings---includ~ insects recorded-mainly Coleoptera, Blattodea, Hemiptera , Orthoptera (Fig. 1), Diptera, Hymenoptera , Neuroptera, Mecoptera and Trichoptera (for common names, see Jarzernbowski, 1989b). Insect remains are generally less abundant at Auclaye than at the nearby C1ockhouse Brickworks, but the fine-grained matrix preserves more detail. Also, insect body parts appear to be more common, probably due to deposition under quieter conditions and less sorting. Many of these parts remain to be identified (hence the long indeterminate column in Fig. 2) although they probably belong to the orders already recorded. The predominance of Coleoptera and dominance of Coleoptera and Blattodea over other orders is typical of the Weald Clay. Note also that aquatic orders (Odonata, Trichoptera) are uncommon in the Clay generally , and that the four most common orders here (Blattodea, Coleoptera, Hemiptera and Orthoptera) are insects with forewings modified for protection (elytra/tegmina); however, the orders are unequally represented. One of the objects of the visit on May 1st was to determine the horizon of the insect -bearing concretions because they are usually found in a fragmentary condition on the pit's old spoil heaps . In situ,

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E. A. JARZEMBOWSKI

- ----/

-

~-

Fig. 1. Hindwing of Panorpidium (= Elcana) sp., (Orthoptera: Elcanidae) with anal lobe folded, Auclaye Brickworks, collected by Harry Woolgar (BMoNH 015765). Impression of conchostracan carapace below base of wing. (Scale line in mm).

fossiliferous rock was eventually located as high as 0.3 m below the top of the pit in the side of a drainage gulley in the north-west corner, and as low as 5-10 em below the present floor of the pit adjacent to the pond. The latter was located by probing the clay with a metal rod (Tony Mitchell). The isolated rock was bagged up for splitting at home and in the lab. The value of such processing was shown by the subsequent recovery of over 100 insect fossils using freeze/thaw to finely split the concretions (T.M.) and the discovery of an unusual and well-preserved parasitoid hymenopteran by the author using a small hammer and chisel. The day had begun wet, but as the rain abated in the afternoon some general surface collecting was possible. On this occasion insect remains were found in clay ironstone and irony claystone as well as in broken phosphatic concretions; one phosphatic nodule was observed to have formed next to clay ironstone. Insects collected included beetle wing cases (Coleoptera elytra) and hindbodies (abdomens), cockroach fore- and hindwings (Blattodea: Mesoblattinidae), a cockroach head shield (pronotum), a male cricket forewing (Orthoptera: Gryllidae) and part of a dragonfly wing (Odonata: Anisoptera). Vertebrate remains are uncommon in this pit but finds included a tooth and scale of Lepidotes-a common Wealden holostean fish-in clay ironstone, and a few isolated

fish vertebrae in the 'clay'. The latter and some phosphatic concretions yielded clam shrimp valves which were often paired and densely packed on certain bedding planes. Some cracked valves and wrinkled elytra suggested compactional movement in the sediment prior to mineralisation. Other invertebrates found in the concretions were the hindbody of an isopod and a few worm burrows including Cochlichnus, the distinctive 'sinuous' traces of nematodes (Jarzembowski, 1988: Fig. 3B. This ichnogenus was misidentified as ct. Belorhaphe by Prentice (1962) and has been illustrated but not named from the Wealden (Lower Tunbridge Wells Sand) of Sussex (Hook Quarry, West Hoathly; Allen, 1962, p. 1.9). Identifiable plant macrofossils are scarce at Auciaye and finds included an isolated leaflet of Weichselia-a common Weald Clay fern-and a shoot of the horsetail Phyllotheca (BMoNH 014890), as well as a coniferous leafy shoot and a number of vertical, pyritised tubes perhaps representing rootlets or stems, all from phosphatic concretions. The pit is degraded and the drainage gulley is the only feature that has been machine excavated since the demise of the brickyard. The hawker dragonfly was found in fresh spoil taken out of the lower end of the gulley. This reconnaissance suggested that a mechanical tum-over of the old spoil heaps could

WEAI.D C I. A Y FIELD MEETING REPORT

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85

ods, driftwood , a barnacle and foramin iferan is found here (Kilenyi & Allen , 1968). Thi s band (Wors sarn's beds 4-10) is very near the base of the pits and intermittently exposed depending on water level. Higher up , Allen (1948, 1959, 1976), Allen & Keith 300_ (1965) have described the sedimentology of B.G.S. no. 3 and adjacent beds ; this bed , like the quasimarine band, is a stratigraphically significant horizon in this region. The distinctive trace fossil Ophiomorpha nodosa Lundgren has been reported as occurring in sandstone and siltstone developments at C1ockhouse, associated with the horsetail Equisetum burchartii Dunker in the siltstone (Kennedy & MacDougall , 1969). In addition, ostracod assemblages 200_ and faunicycles have been studied by Anderson (1985) and molluscs by A. A. Morter (in Worssam, 1978) and Cleevely & Morris (1988). Some of the molluscs have been analysed isotopically (Allen, Keith , Tan & Deines, 1973). Clockhouse has yielded the largest number of insect remains in the Wealden including the wings and body parts of Blattodea, Coleoptera, Diptera , Hem iptera, Hymenoptera , Isoptera, Mecoptera, Neuroptera, 100_ Odonata , Orthoptera , Psocoptera , Raphidioptera and Trichoptera. A selection of these orders is illustrated in Jarzembowski (1977, 1984) and species already < a: described comprise an early termite (see accompanyt< :c t
-

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E. A. JARZEMBOWSKI

Fig. 3. Aff. Chiridotea sp., hindbody (Crustacea: lsopoda: Idoteidae) 015767, -8. Although not shown in the photograph, the crustacean remains at Clockhouse may be distinguished from insects because of their rusty colouration (due to ferruginous replacement of originally calcareous cuticle?) and less disarticulated preservation as above. (Scale line in mm).

1977) like the lenticles (Prentice, 1962). The basin casts and large lenticles were formerly more common because they were dumped on the floor of the Old Pit during Clay extraction. The G.A. visits focused on the New Pit which was deepened during the summer of 1988 exposing the quasimarine band which yielded abundant examples of the cassiopid gastropod Paraglauconia shipbornensis (Mennessier, 1984) and other molluscs. Paraglauconia (formerly called Cassiope) may, like Weichselia, have originally formed part of a mangal (mangrove)-Iike community (Cleevely & Morris, 1988 and references). In the upper part of the pit, blocks of yellowish brown, micaceous, ripple-marked sandstone were examined (Clock house Sand) with Ophiomorpha and desiccation/shrinkage cracks. The trace fossil has been interpreted as a shallow marine indictor but this is doubted by Stewart (1978). On a newly cut terrace way of cracked/jointed mudstone, shelly seams were seen above the Clockhouse Sand with gastropods (large Viviparus), Filosina and a single Paraglauconia? suggesting lowered salinities. Several siltstone scour fills were found on the spoil heap and dislodged, usually broken, on the pit face. The common lenticular examples showed some ripple marks (on top) and well-preserved sole structures, especially groove marks and worm casts but also prod marks and runnel casts (the latter are also known as gutters or elongate flutes; Allen, 1962: Fig. 3). A few

lenticles were capped by reddish, bioturbated mudstone. Insects found included a variety of Coleoptera elytra and some body parts, a few Blattodea and Diptera forewings and solitary examples of Hemiptera, Neuroptera and Odonata (aeschnidiid) wings. Destratified fossils collected included pieces of bone-bed with rolled fish bones, teeth and small pebbles representing lag deposits; runnels packed with ostracods and small Viuiparus ; Weichselia fragments in a piece of hard (phosphatised?) mudstone; and a hard, blue-grey siltstone lenticle with abundant conchostracans unusually preserved 'in the round' and presented by a workman. The latter are being studied by Andrew Ross. In addition, fossils were found weathered out of the 'clay' including fish (a hybodont spine, Hybodus teeth, Lepidotes teeth and scales and teleost scales); reptiles (a crocodile tooth and pieces of pterosaur and turtle bone); a gastrolith (Joyce Austen; see also p. 89) and a fine phosphatic coprolite (Tony Jennings). Dinosaur remains are scarce at Clockhouse, but on the first visit (12vi88) David Cooper kindly displayed a newly prepared vertebra of Iguanodon bernissartensis Boulenger (Fig. 5). He had found this damaged by an excavator in the lower part of the New Pit on a field trip with the West Sussex Geological Society in 1987. Bones of Iguanodon were found here previously, presumably in the Old Pit, c. 10 m down in 1941 by S.E. Winholt and are now in the Horsham Museum.

WEALD CLAY FIELD MEETING REPORT

87

Fig. 5. Dorsal (probably seventh) vertebra of immature Iguanodon bernissartensis Boulenger from the New Pit, Clockhouse Brickworks, D. J. Cooper collection. (Scale: foot ruler) .

4. SMOKEJACKS BRICKWORKS Fig. 4. Spirangium jug/eri Schimper, Upper Weald Clay, silty ironstone, Smokejacks Brickworks (015762). Maximum length 65 mm and width 19 mm (Scale line in mm). This species, reported previously from the older Wealden of East Sussex (Hastings Beds Group : 'Fairlight Clays') is based on what are considered to be the egg cases of freshwater cartilaginous fish (sharks and their relatives: Mueller, 1978). It also occurs in the Lower Weald Clay at the Auclaye Brickworks in phosphatic concretions (found by Amanda Millar: Jarzembowski, 1987) and at the Clockhouse Brickworks in siltstone lenticles where the author has observed a clutch of two. The illustrated specimen is smaller than cases from 'Fairlight Clays' which are about 140 mm long. However, intraspecific size variation may be considerable in some other species based on egg cases (Mueller, 1978). Spirangium cannot be attributed to taxa based on body fossils, but it is noteworthy that at Smokejacks the silty ironstone also yields occasional teeth of the common Wealden shark Hybodus. Such teeth also occur in the

This actively worked pit near Ockley exposes approximately 27 m of Weald Clay below BGS bed no. 5c (Alfold Sand Member: Allen, 1976) which suggests that it is in the Upper Weald Clay of early Barremian age (Allen, 1990; Hughes & McDougall , 1989). A partial section is given by Allen (1981) and we are indebted to Phil Palmer for use of his unpublished complete section during the field trips. In general, the Aifold Sand (less than one metre thick) at the top is underlain by c. 15 m of striped greenish grey and reddish brown silty Clay (laminated soft siltstone at Clockhouse as well as in winnowed bony concentrates containing other fish. However, no cartilaginous fish has been recorded yet in the phosphatic concretions at Auclaye.

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E . A . JARZEMBOWSKt

mudstone) overlying c. 12 m of dark blue-grey Clay. The colour banding is possibly associated with shoaling of the Wealden waters described by Allen (1981). The pit is a proposed S.S.S.I. and famous for having yielded a new theropod dinosaur Baryonyx walkeri (='Claws') in 1983 (Charig & Milner, 1986). Other dinosaur remains found here include Iguanodon and a Titanosaurus-like sauropod (Rivett , 1953). More remains of Iguanodon have turned up recently (David Cooper, personal communication). Insect remain s commonly occur in silty ironstone (iron carbonate) concretions and occasionally in siltstone lenticles and in phosphatic nodules. They are often concentrated in partings or thin layers and include Blattodea, Coleoptera, Diptera (Jarzembowski, 1977: Fig. B), Hemiptera, Hymenoptera, Isoptera, Mecoptera, Neuroptera, Odonata and Orthoptera. Also found in the insectiferous ironstone are burrows and the odd stem or rootlet cast, clay clasts, fish fragments, undescribed isopods, conchostracan carapaces, impressions of molluscan fragments including Filosina, ostracod s and small plant debris amongst which the fusainised leaflets of Weichselia and unfusainised bits of wood may sometimes be recognised. The ironstone concretions also yield egg cases of cartilaginous fish (Figs. 4 & 6), which are usually broken, and impressions of an undescribed aquatic plant (Fig. 7; liverwort?: Dr . David Batten, pers. comm.). The first visit (12vi88) commenced with Bill Walker

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Fig. 7. Liverwort? Smokejacks Brickworks , 015760, - I. Scale line = 10 mm.

Fig. 6. Recent egg case of a heterodont shark showing the spiral structure from Guenther (1880) for comparison with Fig. 4. ( xO.5) .

giving an account of his discovery of Baryonyx and pointing out the horizon from which it came , a light grey Clay on the eastern side of the pit (Palmer's ms no. 9 or saurian bed) . On this and subsequent visits, a band of greenish Clay nearly midway down the pit face in the south-west corner yielded much lignified driftwood and some vertebrate remains including a dozen crocodile teeth, a crocodile scute , part of a pterosaur limb bone , fish (Lepidotes) scales, teeth and

WEALD C L A Y FIELD MEETING REPORT

palate , and a couple of Iguanodon teeth (Chris Mart in, Andrew Ross , David Cooper) . An Iguanodon ? vertebra was found weathered out of the Clay in the south-east comer (David Wilson) plus a group of five gastroliths in the west-south-west face (John Wyley, Pat Martin). On e of the Wyley specimens had undergone at least two phases of deform ation during the Palaeozoic prior to ending up as a reptilian gizzard stone in Lower Cretaceous times (Prof. Perce Allen , pers . comm .) . An insect iferous ironstone concr et ion was found by the auth or in Palmer's ms bed 6 on the first visit and diverse coleopteran elytra and a hemipteran tegmen were collected. These insects were supplemented by a blattodean tegmen and fragm ent of odonatan (aeschnidiid) wing from a loose concretion in the

89

following year. In the meantime, more insect remains (Blattode a: Mesoblattinidae, Coleoptera includ ing Archostemata , Orthoptera and Odonata) were found by Ad rian Parkes in an ironston e concretion from Palmer's ms bed 1. Unusual finds in 1989 included a parting (scour fill) near the base of th e western part of the pit with abundant Weichselia reticulata (Fig. 8.) and rare Phlebopteris dunkeri; an iron -stained lfint artefact (blade) evidently from the top of th e south-west face found by the author; and a phosphatised spiral coprol ite found loose (Michelle Legg) . Th e latter would have been produced by a vertebrate , possibly shark (Duffin, 1979) . Sole structures are not much in evidence on this site , but a siltstone runnel cast was observed in 1988 and another one of ironstone in the following year.

Fig. 8. Pinnae of Weichselia reticulata (Stokes & Webb ) in an ironston e concretion from Palmer's ms bed I , Smokejacks Brickworks (014930, presented by Ton y Mitchell and photographed by Rob ert Warte rs). Maximum length and width of parting 28 and 14 cm respectively. Th is typical Weald Clay fern is beaut ifully reconstructed by Claire Dalby in Alvin (1971, Fig. 3).

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E. A. JARZEMBOWSKI

Fig. 9. Transverse thin section (30 IJm thick) of insect-bearing siltstone from Clockhouse Brickworks, 015769. Scale line=lOmm.

Unfortunately, current directions could not be determined as both runnels were already dislodged. However, no doubt the 'main scientific potential of this pit will clearly be achieved by regular visits to inspect recently excavated faces' (c. Stevens in Gibb, 1988).

ACKNOWLEDGEMENTS

I am indebted to the following for access to Brickworks: Auclaye-Mr. H. Greenwood; Clockhouse-Mr. D. Wilkinson and Smokejacks-Mr. Datson; also to Peter Austen (Seaford) for drawing

Fig. 10. Transverse thin section (30 IJm thick) of insect-bearing ironstone from Smokejacks Brickworks, 015771. Scale line=10mm.

WEALD CLAY FIELD MEETING REPORT

Fig. 7; Messrs R. WaTters (Brighton), D. Cooper (Worthing) and H. Taylor (Liverpool) for photographic assistance; Dr. R. H. Bate for ostracod determinations; Trevor Batchelor for coprolite reference; and Josie Buckwell (Royal Pavilion, Art Gallery & Museums, Brighton) for typing the manuscript. Appendix Thin sections of insect-bearing rocks R. Goldring P.R .l.S ., University of Reading, Whiteknights, Reading, RG62AB

Auclaye Brickworks (014909) Phosphatic concretion with crystals 5-10 Jlm, occasional clay flakes and laminae or patches of quartz silt, the latter probably burrow infills. Yellow to golden brown spores present, crushed and uncrushed and including some bisaccates. Clockhouse Brickhouse (015769) (fig. 9) Quartz siltstone with poikilotopic, calcitic cement. Scattered quartz grains c. 300 Jlm of medium sand grade 'float' in what

91

is otherwise a well-sorted medium siltstone with grains 20-30 Jlm . The silt-grade quartz grains are occasionally coated with green pellicles and associated with grains of chlorite, inertinite particles (fusain, which is common), orange spores and phosphatic vertebrate bioclasts. There is little indication of bioturbation and elongate particles show a parallel lamination . 015770 A very well sorted , uniform fine to medium-grained, micaceous, quartzose siltstone. Associated mineral :green chlorite. Occasional spores and burrows present, the latter vertical and horizontal with muddy fill and often associated with small crystals, probably siderite . The largest burrows are 0.5 mm in diameter. Smokejacks (015771,-2) (Fig. 10) Ironstone concretion from graded, sharp-based and slightly load-cast unit somewhat mottled by bioturbation. Poorly sorted mudstone/quartz siltstone with quartz grains mostly c. 10 Jlm, occasionally c. 30-40 uu», and generally etched. Matrix/cement of sideritie rhombs or aggregations of rhombs. Scattered bioclasts present, mostly associated with coarser base, including paired ostracod valves and fragments of wood (inertinite, one showing distinct uniserial coniferous pitting) plus bone fragments and indeterminate phosphatic fragments. Abundant uncompressed spores present, c. 30 Jlm in diameter, some apparently bisaccate.

References ALLEN, P. 1948. Petrology of a Wealden sandstone at Clock House, Capel, Surrey. Geol. Mag. , 85, 235-41. - - 1959. The Wealden environment: Anglo-Paris Basin. Phil. Trans. R. Soc. Lond., 8242, 283-346, 1 foldout. - - 1962. The Hastings Beds deltas : recent progress and Easter field meeting report. Proc. Geol. Ass ., 73,219-43, pIs 8-10, one foldout. --1976. Wealden of the Weald: a new model. Proc. Geol. Ass., 86,389-437. - - 1977. Correspondence. Proc. Geol. Ass ., 87,433-42. - - 1981. Pursuit of Wealden models . J. Geol. Soc. Lond, 138, 375-405 . - - 1990. Wealden research-ways ahead. Proc. Geol. Ass., 100, 529-64. - - & M. L. KEITH. 1965. Carbon isotope ratios and palaeosalinities of Purbeck-Wealden carbonates. Nature, 208, 1278-80. - - , - -, F. C. TAN & P. DEINES. 1973. Isotopic ratios and Wealden environments. Palaeontology, 16,607-21. ALVIN, K. L . 1971. Weichselia reticulata (Stokes et Webb) Fontaine from the Wealden of Belgium. Mem. Inst. Royal Sci. Nat. Belg., 166, 33 pp, 9 pIs. ANDERSON, F. W. 1985 Ostracod faunas in the Purbeck and Wealden of England. J . Micropalaeontol., 4, 1-68. BRITISH GEOLOGICAL SURVEY & ORDNANCE SURVEY. 1964 'Ten-mile' geological map of Great Britain . Sheet 2. CHARIG, A. J. & A . C. MILNER. 1986 Baryonyx, a remarkable new theropod dinosaur. Nature , London, 324, 359-61. CLEEVELY, R . J . & N. J. MORRIS . 1988. Taxonomy and ecology of Cretaceous Cassiopidae (Mesogastropoda) . Bull. Br. Mus. Nat. Hist. (Geol.), 44, 233-91. DUFFIN , C. J. 1979 Coprolites: a brief review with reference to specimens from the Rhaetic bone-beds of

England and South Wales. Mercian Geol., 7, 191-204 , pIs 21,22. GALLOIS, R. W. , R. G . THURRELL, B. C. WORSSAM & C. R. BRISTOW. 1972. Horsham. Sheet 302 (I :63360) . British Geological Survey, London. GIBB , SIR ALEXANDER & PARTNERS . 1988. Factors affecting the conservation of geological features in quarries and pits. 2 vols. Nature Conservancy Council, Peterborough. GUENTHER; A . C. L. G . 1880. An introduction to the study offishes. xvi + 720 pp. A . & C. Black , Edinburgh. HORNE, D . J. 1988. Cretaceous Ostracoda of the Weald . British Micropalaeontol. Soc. Field Guide, 4, 42 pp. Thames Polytechnic, London. HUGHES, N. F. & A. B. McDOUGALL, 1989. New Wealden correlation for the Wessex Basin. Proc. Geol. Ass ., 100,85-90. JARZEMBOWSKI, E. A., 1977. Insect fossils from the Wealden of the Weald. Proc. Geol. Ass. , 87,443-46. - - 1984. Early Cretaceous insects from southern England . Mod. Geol. , 9,71 -93 , pis I-IV. - - 1987. Wealden insects in Surrey: field trip . Newsl. Brighton Hove Geol. Soc. , 6, 1-2. - - 1988. A new aeshnid dragonfly from the Lower Cretaceous of south-east England . Palaeontology, 31, 763-69. - - 1989a. A fossil aphid (Insecta: Hemiptera) from the Early Cretaceous of southern England. Cretaceous Res., 10,239-48. - - 1989b. A century plus of fossil insects . Proc. Geol. Ass ., 100,433-49. - - 1990. Early Cretaceous zygopteroids of southern England , Odonatologica, 19,27-37. KENNEDY, W. J. & J. D . S. MACDOUGALL. 1969. Crustacean burrows in the Weald Clay (Lower Creta-

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ceous) of South-Eastern England and their environmental significance. Palaeontology, 12,459-71, pis 87, 88. KILENYI, T. I. & N. W. ALLEN. 1968. Marine-brackish bands and their microfauna from the lower part of the Weald Clay of Sussex and Surrey. Palaeontology, 11, 141-62, pis 29, 30. KIRKALDY, J. F. & A. J. BULL. 1948. Note on the section of Weald Clay exposed at the Clock House Brickworks, Capel, Surrey. Proc. Geol. Ass., 59,80-83. MUELLER, A. H. 1978. Ueber Palaeoxyris und andere Eikapseln fossiler Knorpelfische (Chondrichthyes). Freiberger Forschungsh, C342, 7-28.

PRENTICE, J. E. 1962. Some sedimentary structures from a Weald Clay sandstone at Warn ham Brickworks, Horsham, Sussex. Proc. Geol. Ass., 73, 171-85, pis 6,7. RIVETT, W. H. E. 1953. Saurian remains from the Weald Clay at Ockley, Surrey. South-East. Nat. Antiq., 58, 36-37. STEWART, D. J. 1978. Ophiomorpha: a marine indicator? Proc. Geol. Ass., 89, 33-41. TAYLOR, K. 1991. Phosphatic concretions in the Wealden of South-East England. Proc. Geol. Ass., 102, 67-70. WORSSAM, B. C. 1978. The stratigraphy of the Weald Clay. Report Inst. Geol. Sci., 78/11, ii + 23 pp.