PALAEOENVIRONMENTAL INTERPRETATION OF THE TRIASSIC SANDSTONES OF SCRABO, COUNTY DOWN, NORTHERN IRELAND: ICHNOLOGICAL AND SEDIMENTOLOGICAL STUDIES INDICATING A MIXED FLUVIATILE-AEOLIAN SUCCESSION

JAMES O. BUCKMAN, PHILIPS. DOUGHTY,MICHAEL J. BENTON and ANDREW J. JERAM

(Received 19 May 1997)

Abstract

The Sherwood Sandstone Group at Scrabo, Co. Down, NorthernIreland, has been variously interpretedas aeolian or fluviatile. The sedimentological and ichnological data show that these sandstone-dominatedfacies were deposited within a mixed fluviatile-aeolian regime, in which fluviatile processes were responsible for the majorityof the preservedsedimentary sequence. The sequence contains a moderately diverse non-marine ichnofauna comprising the invertebratetrace fossils Biformites, Cruziana/Rusophycus(Isopodichnus), Herpystezoum(Unisulcus), Planolites, 'small arthropodtrackways', 'large arthropodtrackways' (cf. in part Paleohelcura), and the vertebrate trace fossil Chirotherium? (as well as a number of other, presently unnamed, vertebrate footprints). The recorded ichnofauna greatly increases that previously known from the Irish Triassic, comparesfavourably with that from the rest of Europe, and representsthe only known Irish locality for reptiliantrackways.

Introduction north-east, are exposed at Scrabo Hill (Charlesworth 1963). Several Palaeogene The Sherwood Sandstone Group (Triassic) dolerite dykes and sills are exposed at the in north-eastIreland comprises part of a thick southern end of the hill, and these form a sequence of non-marine sediments, with a resistant cap that has shielded the sandstones maximum thickness of 1850m (Parnell et al. against removal by ice during the last 1992), which are rarely exposed and known glaciations. mostly from borehole data. At Scrabo (Fig. 1) Various environmental interpretationshave the Sherwood SandstoneGroup occurs within a been made of the Scrabo succession. The deep trough of Carboniferousto Triassic age succession has been interpretedas representing (Parnell et al. 1992), which is developed on a aeolian conditions (Charlesworth1953; 1963), structuralhigh (the Longford-Down Massif). with the caveat that some parts might have had Approximately 37m of strata, which dip at 50 a waterlain origin (Charlesworth 1953).

Irish Journal of Earth Sciences 16 (1997/8), 85-102.

85 JSTOR: Irish Journal of Earth Sciences, Vol. 16 (1997/1998), pp. 85-102 29/01/2009 17:33

http://www.jstor.org/stable/30002179?seq=2 Page 3 of 5 JSTOR: Irish Journal of Earth Sciences, Vol. 16 (1997/1998), pp. 85-102 29/01/2009 17:33

http://www.jstor.org/stable/30002179?seq=3 Page 3 of 5 JSTOR: Irish Journal of Earth Sciences, Vol. 16 (1997/1998), pp. 85-102 29/01/2009 17:34

http://www.jstor.org/stable/30002179?seq=4 Page 3 of 5 JSTOR: Irish Journal of Earth Sciences, Vol. 16 (1997/1998), pp. 85-102 29/01/2009 17:34

http://www.jstor.org/stable/30002179?seq=5 Page 3 of 5 90 Buckman- Ir. J. Earth Sci. (1997/8) sinuosity, or irregularity,in their path. Cross- marine trace fossil, this should not preclude its cutting of trails is observed. pertinentusage within non-marinestrata. A number of examples of P. beverleyensis Discussion. These trace fossils are comparable appear to be slightly pelleted. Taken in with the 'looped trails' of Irelandet al. (1978). conjunction with their co-occurrence with Such trace fossils could conceivably represent Biformites and other similarities to Biformites, the product of a number of organisms, this suggests that the two were producedby the including gastropods, bivalves, crustaceans, same constructor.Variation within Biformites insects and annelids (Schilfer 1972; Baldwin and similarity to P. beverleyensis can then be 1974; Buckman 1992a; 1992b), and occur over explained in terms of behaviour (ethology) a wide range of environments from marine and/orsubstrate consistency. (Buckman 1992a; 1992b), through marginal- marine (Wright and Benton 1987), to non- Ichnogenus Rusophycus Hall 1852 marine (Irelandet al. 1978; Turner1978). Rusophycus ichnosp. Fig. 5 Ichnogenus Planolites Nicholson 1873 Planolites beverleyensis (Billings 1862) Material and occurrence.K13552 and K27211, Fig. 3a-b two blocks with a number of individuals in variable states of preservation,from locality 1. Material and occurrence. K7997, K13556, several dozen specimens from localities 1 and Description. Smooth, bilobed convex 2. hyporeliefs, maximum relief 2-3mm, width 3mm and length 6mm. Occurring in simple Description. Horizontal endostratal burrows, coffee-bean shaped form, or with slightly comprising convex hyporeliefs on the base of divergentlobes. sandstone beds above thin mudstone horizons. Discussion. The co-occurrence of C. Burrow width 1-4mm, length 10-70mm. Burrows are smooth and consistent in width problematica on the same hand specimen, from the and the clear coffee- along their length, straightto variablyrecurved separation same, bean of the ichnotaxon indicate in the horizontal plane, and curve upwards at shape both ends. These burrows occur in dense assignmentwithin Rusophycus. masses, in which individuals commonly cross- 'Small arthropod trackways' cut each other, producing radiating inter- Fig. 7 penetrating structures, which give the impressionof acute palmatebranching. Material and occurrence. Three observed individuals, one from an unknown horizon at Discussion. Triassic burrows of this general Scrabo (K11550), the others field specimens where is style, particularly palmate branching from locality 1. well developed, are commonly referred to Phycodes curvipalmatum (Pollard 1981). Description. Biserial concave epireliefs, com- However, although the Irish specimens prising indistinct scratchmarks, or two parallel commonly run parallel to each other and faintly impressed narrow grooves. Maximum appear to branch, this is predominantly a width of trackway4mm. feature of cross-cutting caused by over- crowding. Thereforethis materialis assigned to Discussion. It is likely that more than one Planolites, which can in. some cases also be ichnotaxon is included within this group of branched (Pemberton and Frey 1982), and is trace fossils, some possibly referable to further assigned to P. beverleyensis by Diplichnites triassicus (J.E. Pollard, pers. comparison with Pemberton and Frey (1982, comm.); however, the nature of preservation pl. 5, fig. 2). Although Planolites is a common precludestaxonomic assignment. JSTOR: Irish Journal of Earth Sciences, Vol. 16 (1997/1998), pp. 85-102 29/01/2009 17:35

http://www.jstor.org/stable/30002179?seq=7 Page 3 of 5 0) 5-) Cd kb ft

U

1 ;

1 I I

[Ssf4

'f

t52 )\~r~E 8 522 0 8

- JSTOR: Irish Journal of Earth Sciences, Vol. 16 (1997/1998), pp. 85-102 29/01/2009 17:35

http://www.jstor.org/stable/30002179?seq=9 Page 3 of 5 JSTOR: Irish Journal of Earth Sciences, Vol. 16 (1997/1998), pp. 85-102 29/01/2009 17:36

http://www.jstor.org/stable/30002179?seq=10 Page 3 of 5 Ir. J. Earth Sci. (1997/8) - Buckman 95

UNIT, AGE AND LOCALITY TRACE FOSSILS SCRABO SST HELSBY SST FMT WATERSTONES (MERCIA (SHERWOOD SST GROUP), (SHERWOOD SST GROUP), MDST GROUP), SCRABO HILL CHESHIRE BASIN CHESHIRE BASIN

Biformites

Assortedinvertebrate trackways

Isopodichnus/Cruziana/Rusophyc us

Planolitesl/Phycodes curvipalmatum

Herpystezouml'loop trails'

Vertebratefootprints

Thalassinoides

Striated oblique burrows

Small stuffed burrows

Lingulichnus

Diplocraterion

Arenicolites

Palaeophycustriadicia

Fig. 11--Comparison of the Triassic ichnofaunasof the CheshireBasin and Scrabo Hill; data on the Cheshire Basin from Pollard (1981), indicating the similarity between the Scrabo sandstone ichnofauna and that of the Helsby Sandstone Formation. trackways' and 'small arthropod trackways' laterally into Facies II. Pin-stripingoccurs on a occur within this facies. Small-scale water- millimetre scale, with alternationof medium- escape/liquefaction structuresare occasionally to fine-grained sandstone laminae. Highly observed within the cleaner sandstonefraction. porous, it weathers faster than the other Additionally rain-pits (maximum diameter observed sandstones. 10mm) and pinhole cavities (1mm or less in diameter)are observed within this facies. Facies VII:Desiccated mudstones The mudstones that typify this facies occur Facies V: Wavy-laminatedsandstones in beds, up to 100mm thick, that are laterally Lithologically similar to Facies IV, but discontinuous, horizontal in nature, or occa- differentiated on the basis of its irregular, sionally drape small dune features. They wavy, discontinuous lamination/bedding; commonly exhibit desiccation surfaces (Fig. occurs directly above Facies IV, with a 10a-c), and may have more than one gradationalboundary. desiccated surface within them. Sand-filled desiccation cracks commonly display Facies VI: Pin-stripedsandstones ptygmatic structure owing to compaction This cross-bedded facies occurs as a (Fig. 10c). Small lens- or dune-shaped sand sandstone unit up to im thick, which passes bodies are occasionally developed within the 96 Buckman- Ir. J. Earth Sci. (1997/8) thicker mudstone horizons, which commonly interbedded mudstone beds and lamellae exhibit asymmetric and symmetric rippled indicates that these sandstoneshave a fluviatile surfaces with superimposed sand-filled origin. The facies representsdeposition within desiccation cracks. The latter sandstonebodies a major fluviatile channel area-a conclusion contain Planolites, Biformites and isolated that is supportedby the commonly channelised vertebratefootprints. base of the facies. The channelised conglomeratic sandstones Environment (Facies II) representdeposition within smaller- scale ephemeral channels (cf. Cowan 1993). Environmentalinterpretation is based mostly That deposition was intermittentis evidenced on the observed sedimentary structures, by the associated occurrence of mud-drapes, particularly the physical (inorganic) sedi- desiccated surfaces and rip-upclasts. mentary structures, with supportive infor- The only trace fossils associated with either mation gleaned from the associated trace type of fluviatile 'channel' deposit are fossils. None of the typical marineor marginal- vertebrate footprints. However, the latter are marine ichnogenera recorded from other not restricted to fluviatile facies, but are also Triassic deposits, such as Diplocraterion, recorded from elsewhere within aeolian Thalassinoides, Lingulichnus, Arenicolites or deposits (see e.g. McKeever 1991; 1994), as Palaeophycus striatus, are known, precluding well as intertidalsettings (Pollard 1981). Such the possibility of a marginal-marine,estuarine would be expected given the more mobile, or intertidalregime of deposition (J.E. Pollard, non-facies-dependent nature of the reptilian pers. comm.). The trace fossils at Scrabo are, producersof the trackways. however, similar to those of the Helsby Sandstone Formation (Sherwood Sandstone Overbank/'lacustrine'environments Group) described by Pollard (1981) (Fig. 11), The thinly bedded sandstones (Facies IV), which are of a fluviatile origin (Pollard 1981). with mostly tabulargeometry, are interpretedas Three major environmental settings can be overbank floodplain deposits, with rippled recognised from the Scrabo succession: horizons nearer to the active channels. The fluviatile 'channel' (Facies I, II), overbank/ recorded RI of 5-26 is of interest, as it 'lacustrine' (Facies IV, VII) and aeolian/ encompasses the recorded fields for both aeolian reworked (Facies III, V, VI), in which aeolian and aqueous current ripples (Tanner fluviatile and ephemeral lacustrine environ- 1967; Selley 1992; Tucker 1993). At one ments of deposition are dominantlypreserved, measured section, ripples exhibit a progressive with minor aeolian elements. Aeolian upwarddecrease in RI (14-26, 7-18, 5-6, 6-7), processes may have been more common than indicating a possible change from aeolian to evidenced within the preserved sedimentary aqueous currentripples. The latter is unlikely, record, as witnessed by the common however, given the association with occurrence of rounded quartz and feldspar Cruziana/Rusophycus (Isopodichnus), indi- grains. Although some of the latter may have cating subaqueous deposition throughout. been reworked from the underlying Permian Additionally,the occurrenceof C. problematica (Parnell et al. 1992), they may also have been suggests that temporary freshwater-brackish reworked by river systems flowing through ponds may have been developed. The transient contemporaneousaeolian dune fields. inhospitablenature of these ponds is indicated by the restrictionof the ichnofauna wholly to Fluviatile 'channel' environments repichnia(Cruziana/Rusophycus, Herpystezoum, The cross-bedded sandstones of Facies I are 'small arthropodtrackways', 'large arthropod interpretedas fluviatile in origin, as they lack trackways'). Pinhole cavities (?after gypsum) highly inclined cross-lamination typical of recordedfrom this facies have also been noted many but not all aeolian dunes. The occurrence by Thompson (1970b) from 'striped' facies of mud-drapes, occasional rip-up clasts, and within the Waterstonesof the Cheshire Basin, Ir. J. Earth Sci. (1997/8) - Buckman 97 where they are recorded from river floodplain 1993), can be taken to be indicative of aeolian or lagoonal environments.The environmentof dune deposition. Additionally, a lack of deposition was, therefore,aqueous, but liable to mudstone intraclastswithin this facies suggests periods of drying out with the possible that it is likely to be of aeolian origin, as do its production of minor amounts of evaporitic relatively high permeabilityand the degree of minerals. Temporarysubaerial exposure is also grain roundness and sorting (see criteria in indicated by the presence of trackways Cowan 1993, 234). Differentiation of this attributable to scorpions ('large arthropod facies from that of fluviatile Facies I is often trackways' types I and II), which are non- difficult owing to the nature of exposure at aquatic. Scrabo. However, Facies VI appears to be The desiccated mudstones (Facies VII) are subordinate. hard to place in terms of a depositional model. The lateral discontinuity of these mudstones Environmentalsummary suggests that they may represent abandoned The Scrabo palaeo-environment can be channel sections that have subsequently silted interpretedas representingdeposition within a up. However, the mudstones lack the plug- small basin, comprisingboth fluviatile (channel shaped morphology typical of abandoned and overbank)and aeolian processes, in which channel sections and their lateral discontinuity aeolian activity may have been temporally is a feature of cut-down by Facies I. It is more dominant, but in which fluviatile activity has appropriate, therefore, to consider that this producedthe bulk of the preservedsedimentary facies represents overbank deposits, with record. By comparison with similar deposition during flood events, resulting in environmentsin the East Irish Sea Basin and localised, shallow, ephemeral lakes, prone to the CheshireBasin, it can be suggested that the drying out. The lakes were inhabited by the river system was dominatedby low to moderate constructorsof the feeding/habitationburrows sinuosity braided channels (see Thompson Planolites and Biformites and crossed by 1970a; Pollard 1981; Cowan 1993; Meadows reptiles that left distinctive trackways. and Beach 1993).

Aeolian environments Substrate conditions The occurrence of in situ curled mudflakes (Facies III) along the tops of Facies II and The trace fossils present in Facies VII within Facies I indicates deposition under (dessicated mudstones) and Facies IV (thinly aeolian influence (Smith et al. 1991; bedded sandstones) can be used to extract N. Trewin, pers. comm.), since the delicate additional information concerning changes in mudcurl structures can only be explained if substrate consistency and to document they were buried by aeolian processes. This is subaerial exposure. Planolites and Biformites important,as it indicates the intermittentnature within Facies VII are closely associated, of water flow within the river channel systems commonly display cross-cutting relationships, of the palaeo-Scraboarea. and are of a similar size and shape. As they The wavy-laminated sandstones (Facies V) differ mainly in the nature of their outer appear to be identical to the sheetflood facies burrow ornament,and the presence or absence of Cowan (1993, fig. 9), from the Sherwood of a lining, these two burrowsystems are likely Sandstone Group of the East Irish Sea Basin, to representthe work of the same constructor. representing aeolian reworked fluviatile Differences can be interpretedas reflecting a deposits. The latter interpretationfits well with progressive change in the consistency (water- the Scrabo facies, which occurs directly above content) of the substrate, Biformites Facies IV, fluviatile, sheetflood deposits. constructed within a soft substrate, and The distinctive pin-striped lamination of Planolites within a firmer substrate;reflecting Facies VI, although not exclusively associated a progressive drying out, culminating in the with aeolian depositional systems (Cowan productionof desiccation cracks. However, all 98 Buckman- Ir. J. Earth Sci. (1997/8) burrows were constructedwithin a subaqueous ichnofaunas,irrespective of age, is their lack of environment. pascichnia (see Pollard 1981), which could be The trace fossils associated with Facies IV used in conjunction with the typical low also provide additionalinformation. Cruziana/ diversity of non-marine ichnofaunas (Miller Rusophycus(Isopodichnus) on the bases of the 1984), as well as type of ichnotaxa, to further rippled sandstones represents the activities of differentiate non-marine from marine branchiopodswithin an aqueous freshwateror environments. Features such as the lack of brackish environment (see Pollard 1985). On pascichnia and low ichnodiversitymay be used the rippled upper surfaces, Herpystezoummay in conjunctionwith the ichnospecies present to representthe locomotory efforts of a numberof identify non-marine facies from the European organisms within either an aqueous or sub- Triassic and possibly within a wider strati- aerial environment (Buckman 1992; 1992b), graphic and geographic context. Nevertheless, but the occurrence of the 'large arthropod some care must be taken with this approach,as trackways' (the tracks of scorpions) indicates it is often difficult to pigeon-hole ichnospecies that the pools of water in which Cruzianawere in respect of their interpreted ethology. produced must have been ephemeral. The two Additionally, ichnofauna cited as being from 'large arthropod trackways' contrast in their marginal-marineenvironments commonly also sharpness of definition, which can chiefly be lack pascichnia, and may exhibit a marked explained either as a factor of toponomy restriction in ichnodiversity. Further,the non- (surface track v. undertrack,see Goldring and marineMermia ichnofacies, recently erected by Seilacher 1971) or sediment consistency. It is Buatois and Mingano (1995), is characterised here postulated that the two styles of preser- by the occurrenceof pascichnia. vation represent different substrate conditions as the sediments dried out. The trace fossils of Ichnofacies/ichnocoenoses Facies IV indicate,therefore, repeated cycles of waterlain deposition in shallow ephemeral Increasedinterest in non-marineichnofaunas pools that intermittentlydried out. has considerably advanced the knowledge of such assemblages, with the examination of Comparison with other non-marine environments including aeolian, lacustrine, ichnoassemblages alluvial, fluvial and palaeosols (Bromley and Asgaard 1979; Retallack 1984; Ekdale and A comparisonof the ethological distribution Picard 1985; Thoms and Berg 1985; Andrews of the Scrabo ichnofauna with other Triassic 1991; Gierlowski-Kordesch 1991; Pickerill non-marine ichnofaunas from Germany, 1992; Sarkarand Chaudhuri1992; Hasiotis et Greenland, the UK and India (Bromley and al. 1993; Genise and Bown 1994; Buatois and Asgaard 1979; Pollard 1981; Sarkar and Mdngano 1995). Pemberton et al. (1992) Chaudhuri 1992) indicates that these do not indicated the likelihood that a variety of non- possess pascichnia (or rarely so), as is also the marine ichnofacies had yet to be defined, in case for the ichnofauna described from a addition to the standardScoyenia ichnofacies Jurassic aeolian deposit (Ekdale and Picard for such environments. Subsequently the 1985) and a numberof Carboniferousfluviatile Termitichnus and Mermia ichnofacies have sandstones (Buckman 1992b; Pickerill 1992, been erected as additional non-marine Rusophycus ichnocoenosis). These ichnofauna ichnofacies (Smith et al. 1993; Buatois and are otherwise of variableethological and faunal Mangano 1995). The Irish material can be composition. Although not all marine accommodatedwithin the Scoyenia ichnofacies ichnofauna possess pascichnia (Buckman (see Buatois and Mingano 1995, table 2). In 1992b, fig. 2.3c), many do, particularlythose respect of non-marine environments, the within the Cruziana-or Nereites-ichnofacies.It ichnofaunacan more usefully be thought of in is tempting, therefore, to draw the conclusion terms of its constituent ichnocoenoses. A that a characteristic feature of non-marine numberof ichnocoenoses have been recognised Ir. J. EarthSci. (1997/8) - Buckman 99 within non-marine ichnofacies (Bromley and by the occurrence of aeolian dune facies Asgaard 1979; Pollard et al. 1982; Pickerill (Facies VI), the preservation of curled 1992), and it is possible to consider the Scrabo mudflakes (Facies III), adhesion ripples ichnofauna in terms of two distinct and warts, and wind scours (within partsof ichnocoenoses. Ichnocoenosis 1 is represented Facies I), and reworked floodplain by Cruziana/Rusophycus (Isopodichnus), deposits (Facies V). Aeolian processes Herpystezoum,'large arthropodtrackways' and may have been temporallymore important, 'small arthropod trackways' (repichnia but have a low preservation potential in dominated), within thinly bedded typically comparisonto their fluviatile counterparts. rippled facies (Facies IV), while ichnocoenosis 3. Trace fossils in the Scrabo area are mainly 2 includes Planolites, Biformites, and minor limited to fluviatile units, and then Chirotherium?(fodinichnia dominated),within typically only to those comprising a more thickly bedded sandstones containing mixture of sandstone and mudstone well-defined mudstone horizons and (overbank/'lacustrine'). This limits the desiccation cracks (see Fig. 8). Ichnocoenosis 1 resolution of ichnology as an environ- represents a transient (overbank/'lacustrine') mental tool in mixed fluviatile-aeolian environment dominated by repichnia, which successions. However, Biformites, was occasionally subaerially exposed-an Cruziana/Rusophycus and Planolites interpretationthat is supportedby the observed clearly indicate subaqueousenvironments, passage of the dominantly subaqueous Facies whereas 'large arthropod trackways' IV into the wind-reworkedFacies V (Fig. 8). (produced by scorpions) indicate subaerial Ichnocoenoses a, b and d of Pollard et al. exposure. The mode of preservation of a (1982) from ephemeral lacustrine deposits of number of the recorded vertebrate the Middle Devonian Hornelen Basin of trackwaysalso indicates aeolian influence. Norway are also dominatedby repichnia, as is In addition, trace fossils can determine the Isopodichnus ichnocoenosis (Pollard 1981; environmental parameters such as 1985), and both are closely comparable to substrateconsistency. ichnocoenosis 1, with the exception that the 4. As with many other non-marineScoyenia former are wholly aquatic. Ichnocoenosis 2 ichnoassemblages,the limited diversity (in representsan ephemeralfluviatile environment comparisonto marineassemblages) and lack dominatedby fodinichnia (?domichnia),which of pascichnia(dominance of fodinichniaand was occasionally subaeriallyexposed, resulting repichnia)may be useful as an indicatorof in the production of desiccation cracks. Both non-marineconditions, but caution must be ichnocoenoses were thereforeinitially aquatic, employed when trying to interpret the and subsequentlysubaerially exposed, although ethological significance of trace fossils to differing degrees within different within non-marineenvironments. environmental/lithologicalsettings.

Conclusions Acknowledgements 1. The sedimentology and ichnofauna of the Sherwood Sandstone Group at Scrabo The authors thank the Department of the indicate mainly fluviatile processes of Environment(Northern Ireland) for permission deposition. This is confirmed by to collect from Scrabo over a numberof years. comparison with the Triassic of the This work has benefited from constructive Cheshireand East Irish Sea Basins. comments by a numberof people, in particular 2. Although most of the sequence is inter- John Pollard, Roland Goldring and Nigel preted as representing fluviatile channel Trewin, as well as by anonymous reviewers. and overbank floodplain/'lacustrine' We also express our thanks for the donation of deposits, aeolian processes are indicated specimens collected by ChrisMaguire. 100 Buckman- Ir. J. Earth Sci. (1997/8)

References d'Orbigny, A. 1842 Voyage dans l'Am'rique meridionale (le Brdsil, la Rpublique oriental de l'Uruguay, la RdpubliqueArgentine, la Patagonie, la Ripublique du Andrews,J.E. 1991 Unusualnonmarine burrows from the Chili, la Rtpublique de Bolivia, la Rtpublique du MiddleJurassic of Scotland.Ichnos 1, 247-53. Pdron) extcutpendant les annees 1826, 1827, 1829, Ashley,H. 1946 Cheirotheriumfootprint found at Scrabo 1830, 1831, 1832, et 1833: vol. 3, part 4 Hill, Co. Down. Irish Naturalists' Journal 8, 332. (Paltontologie). Paris.Pitois-Levrault. Baldwin,C.T. 1974 The controlof mudcrackpatterns by Ekdale,A.A. and Picard,M.D. 1985 Trace fossils in a small gastropod trails. Journal of Sedimentary Jurassiceolianite, Entrada Sandstone, Utah. In H.A. Petrology 44, 695-7. Curran (ed.), Biogenic structures: their use in Billings, E. 1862 New species of fossils from different interpreting depositional environments. Society of partsof the Lower,Middle and Upper Silurian rocks EconomicPaleontologists and Mineralogists,Special of Canada.In Paleozoicfossils, vol. 1 (1861-5), Publication35, 3-12. 96-168. GeologicalSurvey of Canada. Genise,J.F. and Bown, T.M. 1994 New Miocenescarabeid Bown, T.M. and Kraus,M.J. 1983 Ichnofossilsof the and hymenopterousnests and Early Miocene alluvial Willwood Formation (Lower Eocene) (Santacrucian) paleoenvironments, Patagonia Bighorn Basin, north-west Wyoming USA. Argentina.Ichnos 3, 107-17. Palaeogeography, Palaeoclimatology, Palaeoecology Gierlowski-Kordesch,E. 1991Ichnology of an ephemeral 43, 95-128. lacustrine/alluvialplain system:Jurassic East Berlin Brady,L.F. 1947 Invertebratetracks from the Coconino Formation,Hartford Basin, USA. Ichnos 1, 221-32. Sandstone of northern Arizona. Journal of Gilmore,C.W. 1926 Fossil footprintsfrom the Grand Paleontology 21, 466-72. Canyon. SmithsonianMiscellaneous Collections 77. Brady,L.F. 1961A new speciesof PaleohelcuraGilmore Goldring,R. and Seilacher,A. 1971 Limulidundertracks from the Permianof northernArizona. Journal of and their sedimentological implications. Neues Paleontology 35, 201-2. Jahrbuch fiir Geologie und Pdlaontologie 137, Bromley,R. and Asgaard,U. 1979 Triassicfreshwater 422-42. ichnocoenosesfrom Carlsberg Fjord east Greenland. Hall, J. 1852 Palaeontology of New York,vol. 2. Albany. Palaeogeography, Palaeoclimatology, Palaeoecology Hasiotis,S.T., Aslan, A. and Bown, T.M. 1993 Origin, 28, 39-80. architecture,and paleoecologyof the early Eocene Buatois, L.A. and Mngano, M.G. 1995 The continental ichnofossil Scaphichnium hamatum- paleoenvironmentaland paleoecologicalsignificance integrationof ichnologyand paleopedology. Ichnos 3, of the lacustrineMermia ichnofacies: an archetypical 1-9. subaqueousnonmarine trace fossil assemblage. Ichnos Hitchcock, E. 1848 An attemptto discriminateand 4, 151-61. describethe animalsthat made the fossil footmarksof Buckman,J.O. 1992a Palaeoenvironmentof a Lower the UnitedStates, and especiallyof New England. Carboniferous sandstone succession northwest Memoir of the American Academy of Arts and Ireland:ichnological and sedimentological studies. In Science, new series 3, 129-256. J. Parnell (ed.), Basins on the Atlantic seaboard: Ireland,R.J., Pollard, J.E., Steel, R.J. and Thompson, D.B. petroleum geology, sedimentology and basin 1978 Intertidalsediments and tracefossils from the evolution.The GeologicalSociety, London, Special Waterstones (Scythian-Anisian?) at Daresbury, Publication62, 217-41. Cheshire. Proceedings of the Yorkshire Geological Buckman,J.O. 1992b Trace fossils from the Lower Society 41, 399-436. Carboniferousof northwestIreland. Unpublished Kaup,J.J. 1835 Tierfihrtenbei Hildburghausen.Neues doctoralthesis, Queen's University Belfast. Jahrbuch filr Mineralogie, Geologie, und Charlesworth, J.K. 1953 The geology of Ireland: an Paldontologie, 327-8. introduction.Edinburgh and London. Oliver and Kennedy,W.J. and MacDougall,J.D.S. 1969 Crustacean Boyd. burrowsin the Weald Clay (LowerCretaceous) of Charlesworth, J.K. 1963 Historical geology of Ireland. south east England and their environmental Edinburghand London. Oliver and Boyd. significance.Palaeontology 12, 459-71. Cowan,G. 1993Identification and significanceof aeolian Linck, 0. 1949 Lebens-Spurenaus dem Schilfsandstein deposits within the dominantlyfluvial Sherwood (Mittl. Keuperkm 2) NW-Wtirttembergsund ihre SandstoneGroup of the EastIrish Sea BasinUK. In BedeutungfOr die Bildungsgeschichteder Stufe. C.P. Northand D.J. Prosser(eds), Characteristicsof Verein fUr Vaterlandische Naturkunde in fluvial and aeolian reservoirs. The Geological Wtrttemberg,Jahreshefte 97-101, 1-100. Society, London, Special Publication73, 231-45. McKeever,P.J. 1991 Trackwaypreservation in eolian Delair, J.B. and Sarjeant, W.A.S. 1985 History and sandstonesfrom the Permian of Scotland.Geology 19, bibliography of the study of fossil vertebrate 726-9. footprints in the British Isles: supplement 1973-83. McKeever,P.J. 1994 A new vertebratetrackway from the Palaeogeography, Palaeoclimatology, Palaeoecology Permianof Dumfriesand Galloway. Scottish Journal 49, 123-60. of Geology30, 11-14. Ir. J. Earth Sci. (1997/8) - Buckman 101

Meadows, N.S. and Beach, A. 1993 Structuraland climatic study of fossil vertebratefootprints in the British Isles. controls on facies distributionin a mixed fluvial and Palaeogeography, Palaeoclimatology, Palaeoecology aeolian reservoir:the Triassic Sherwood Sandstonein 16, 265-378. the Irish Sea. In C.P. North and D.J. Prosser (eds), Sarkar, S. and Chaudhuri, A.K. 1992 Trace fossils in Characteristics of fluvial and aeolian reservoirs, Middle to Late Triassic fluvial redbeds, Pranhita- 247-64. The Geological Society, London, Special GodavariValley, south India.Ichnos 2, 7-19. Publication73. Schlfer, W. 1972 Ecology and palaeoecology of marine Melchior, R.C. and Erickson, B.R. 1979 Paleontological environments.Edinburgh. Oliver and Boyd. notes on the Wannagan Creek Quarry site Schindewolf, O.H. 1921 Studien aus dem Marburger (Paleocene-north Dakota): Ichnofossils I. Scientific BuntsandsteinI, II. Senckenbergiana3, 33-49. Publications of the Science Museum of Minnesota, Seilacher, A. 1978 Use of trace fossil assemblages for new series 4, 3-16. recognising depositional environments. Society of Miller, M.F. 1984 Distribution of biogenic structures in Economic Paleontologists and Mineralogists, Short Palaeozoic non-marine and marginal marine Courses 5, 167-81. sequences: an actualistic model. Journal of Selley, R.C. 1992 Ancient sedimentary environments. Paleontology 58, 550-70. London.Chapman and Hall. Nicholson, H.A. 1873 Contributionsto the study of the Smith, R.A., Johnston, T.P. and Legg, I.C. 1991 Geology errant annelides of the older Paleozoic rocks. of the countryaround Newtownards. London. HMSO. Proceedings of the Royal Society of London 21, Smith, R.M.H., Mason, T.R. and Ward, J.D. 1993 Flash- 288-90 (also Geological Magazine 10, 309-10). flood sediments and ichnofacies of the Late Parnell, J., Monson, B. and Buckman, J. 1992 Excursion Pleistocene Homeb Silts, Kuiseb River, Namibia. guide: basins and petroleum geology in the north of SedimentaryGeology 85, 579-99. Ireland. In J. Parnell (ed.), Basins on the Atlantic Swinton, W.E. 1960a The history of Chirotherium. seaboard: petroleum geology, sedimentology and Liverpool and Manchester Geological Journal 2, basin evolution, 449-64. The Geological Society, 443-73. London, Special Publication62. Swinton, W.E. 1960b A chirotheridfrom Scrabo Hill, Co. Pemberton, S.G. and Frey, R.W. 1982 Trace fossil Down. Irish Naturalists' Journal 13, 145-6. nomenclature and the Planolites-Palaeophycus Tanner, W.F. 1967 Ripple mark indices and their uses. dilemma. Journal of Paleontology 56, 843-8 1. Sedimentology9, 89-104. Pemberton, S.G., Frey, R.W., Ranger, M.J. and Thompson, D.B. 1970a Sedimentation of the Triassic Maceachern, J. 1992 The conceptual framework of (Scythian) red pebbly sandstones in the Cheshire ichnology. In S.G. Pemberton (ed.), Applications of Basin and its margins. Geology Journal 7, 183-261. ichnology to petroleum exploration. SEPM Core Thompson, D.B. 1970b The stratigraphyof the so-called Workshop 17, 1-32. Keuper Sandstone Formation (Scythian-Anisian) in Pickerill, R.K. 1992 Carboniferousnonmarine invertebrate the Permo-TriassicCheshire Basin. QuarterlyJournal ichnocoenoses from southernNew Brunswick,eastern of the Geological Society, London 126, 151-81. Canada.Ichnos 2, 21-35. Thoms, R.E. and Berg, T.M. 1985 Interpretationof bivalve Pollard,J.E. 1981 A comparisonbetween the Triassic trace trace fossils in fluvial beds of the basal Catskill fossils of Cheshireand south Germany.Palaeontology Formation (Late Devonian), eastern U.S.A. In H.A. 24, 555-88. Curran (ed.), Biogenic structures: their use in Pollard, J.E. 1985 Isopodichnus, related arthropod trace interpreting depositional environments. Society of fossils and notostracans from Triassic fluvial Economic Paleontologists and Mineralogists, Special sediments. Transactions of the Royal Society of Publication35, 13-20. Edinburgh,Earth Sciences 76, 273-85. Trewin, N.H. 1976 Isopodichnus in a trace fossil Pollard, J.E., Goldring, R. and Buck, S.G. 1993 assemblage from the Old Red Sandstone. Lethaia 9, Ichnofabricscontaining Ophiomorpha:significance in 29-37. shallow-water facies interpretation.Journal of the Trewin, N.H. 1995 A draft system for the identification Geological Society, London 150, 149-64. and description of arthropod trackways. Pollard, J.E., Steel, R.J. and Undersrud, E. 1982 Facies Palaeontology 37, 811-23. sequences and trace fossils in lacustrine/fan delta Tucker, M. 1993 The field description of sedimentary deposits, Hornelen Basin (M. Devonian), western rocks. Chichester.Wiley. Norway. SedimentaryGeology 32, 63-87. Turner, B.R. 1978 Trace fossils from the Upper Triassic Retallack, G.J. 1984 Trace fossils of burrowingbeetles and fluviatile Molteno Formation of the Karoo bees in an Oligocene paleosol, Badlands National (Gondwana) Supergroup, Lesotho. Journal of Park, South Dakota. Journal of Paleontology 58, Paleontology 52, 959-63. 571-92. Wilson, H.E. 1972 Regional geology of Northern Ireland. Sadler, C.J. 1993 Arthropodtrace fossils from the Permian Belfast. HMSO. De Chelly Sandstone, northeasternArizona. Journal Wright, A.D. and Benton, M.J. 1987 Trace fossils from SofPaleontology 67, 240-9. Rhaetic shore-face deposits of Staffordshire. Sarjeant,W.A.S. 1974 A history and bibliography of the Palaeontology 30, 407-28. 102 Buckman- Ir. J. Earth Sci. (1997/8)

Young, R. 1883 In Report of OrdinaryMeeting. Report of the Proceedings of the Belfast Naturalists' Field Club, series ii, 2 (for 1881-2), 116-18.

JAMES O. BUCKMAN, MICHAELJ. BENTON, PalaeobiologyUnit, Departmentof Geology, Departmentof Geology and Applied Geology, Bristol University, University of Glasgow, Bristol BS8 IRJ, Glasgow G12 8QQ, England. Scotland.

PHILIPS. DOUGHTY and ANDREW J. JERAM, Ulster Museum, Belfast BT9 5AB, NorthernIreland.