Trace Fossils in a Lower Palaeozoic Submarine Canyon Sequence - the Siegas Formation of Northwestern New Brunswick, Canada

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MARITIME SEDIMENTS AND ATLANTIC GEOLOGY 37 Trace fossils in a Lower Palaeozoic submarine canyon sequence - the Siegas Formation of northwestern New Brunswick, Canada

R.K. Piakerill3 Department of Geology University of New Brunswick, Fredericton, New Brunswick* Canada E3B 5A3

The Siegas Formation (Silurian - early Llandovery) of northwestern New Brunswick represents, In part, an ancient example of a submarine canyon sequence, erosive into and partially coeval with the Carys Mills For- mation of late Ordovician—middle Llandovery age. The canyon succession contains a moderately diverse ichnofauna consisting of Buthotrephie, Chondrites, Cochliohnue anguineue, Diplichnitee, Fucueopeie, Gordia arauata, Gordia, Gyrochorte, Helminthoida labyrinthica, Helminthopeie of. abeli, Neonereitee bieerialie, Neonereitee unieerialie, Planolitee beverleyeneie, Protopaleodictyon, Scalarituba mieeourieneie and Skolithoe. These trace fossils are described in detail. Contrary to previous predictions that dwelling burrows and associated traces would predominate in submarine canyon sequences, the Siegas Formation contains traces produced essentially by vagile sediment eaters. This Is perhaps best explained by the absence within the canyon, at least for the majority of time, of sufficiently strong bottom currents, which precluded inhabitation by an active and abundant suspension feeding population. Instead, the sediments probably contained sufficiently abundant organic detritus to support an active population of infaunal sediment feeding organisms.

Situee au nord-ouest du Nouveau-Brunswick, la formation de Siegas (Silurien — Llandovery inferieur) rej>- resente, en partie, un exemple ancien de sequence de canyon 60us-marin; elle recoupe la formation de Cary6 Mills (Ordovicien superieur —Llandovery moyen) et est en partie contemporaine a cette derniere. On rencon- tre dans la sequence une ichnofaune moderement diverse comprennant Buthotrephie, Chondrites, Cochliohnue anguineue, Diplichnitee, Fucueopeie, Gordia arauata, Gordia, Gyrochorte, Helminthoida labyrinthica, Helmin- thopeie of. abeli, Neonereitee bieerialie, Neonereitee unieerialie» Planolitee beverleyeneie, Protopaleo- dictyon, Scalarituba mieeourieneie et Skolithoe. Ce6 traces fossiles sont decrites en detail. Selon les predictions anterieures, les terriers d'habitation et les traces connexes devraient predominer dans les sequences de canyon sous-marin mais contrairement a ceci, la formation Siegas contient plutot des traces produites essentielleinent par des ingesteurs de sediment vagiles. Au mieux, ceci pourrait s'expliquer par 1*exclusion d'une population active et abondante d'animaux filtreurs, due a 1*absence dans le canyon, au tnoins la plupart du temps, de courants de fond significatifs. Au lieu de cela, les sediments devaient con- tenir suffisamment de detritus organiques pour accomoder une population active d* organismes endobiontes limnivores.

(Traduit par le journal]

INTRODUCTION associations and sediment emplace- Oceanographic research has de- ment mechanisms (e.g. Stanley and monstrated that penetration and Bertrand 1979). stirring of sediment by benthic One exception is the recent do- and other organisms is a common cumentation by Hayward (1976) of phenomenon in modern submarine the trace fossils from a Miocene canyons (e.g. Shepard and Dill submarine canyon sequence in New 1966, Trumbull and McCamis 1967, Zealand. Hayward described Tigil- Dillon and Zimmerman 1970, Heezen lites, Saalarituba3 Planolite s and Hollister 1971, Scott and and branching "Planolites"*, from Birdsall 1978, Valentine et al. the unconsolidated sediments of 1980). Yet little research has the canyon floor and Tigillites, thus far been undertaken on the Rhizooorallium and several varie- nature of trace fossils and trace ties of horizontal and inclined fossil assemblages in ancient sub- branching burrows from the semi- marine canyon sequences. In part consolidated but unlithified can- this has arisen from the inherent yon walls. More recently Crimes difficulties of recognizing an- (1977) produced a table which, in cient submarine canyons but also part, recorded both the known and by research workers placing more anticipated ichnofaunas of ancient emphasis on their detailed facies submarine canyon sequences. This * Strictly speaking branching forms are I available for the ichnogenus Planolites (Hantzschel 1975).

MARITIME SEDIMENTS AND ATLANTIC GEOLOGY 17, 36-58 (1981) 38 R.K. PICKERILL paper is therefore intended to Clastic Belt and/or Aroostoock- document the trace fossils occur Matapedia Carbonate Belt by Ayrton ring in an ancient submarine can et at. (1969). In terms of re yon sequence and to add to the cently proposed plate tectonic data presented by Crimes {ib id .) models (Rast and Stringer 1980) so that eventually more realistic the trough represents a remnant and predictable models will be of the Lower Palaeozoic Iapetus realized. The definition of a Ocean. submarine canyon adopted here is The Siegas Formation is of res the same as that proposed by tricted areal extent, persisting Heezen and Hollister (1971) i.e. some 11 km to the north and north "any persistent valley found on west of Siegas and 9.5 km to the the continental margin regardless south and southeast. In thickness of shape or size", or alternatively it ranges from between c. 107-244 but less specifically, following m in the Siegas area to zero at Bates and Jackson (1980), a "gen its northwestern and southeastern eral term for all valleys of the limits where it passes into coeval deep-sea floor". strata of the Carys Mills Forma tion (Hamilton-Smith 1971a).Both STRATIGRAPHIC BACKGROUND this latter formation and the Strata under consideration in Siegas Formation are conformably this paper are referred to as the overlain by the Perham Group of Siegas Formation of Hamilton- post-early Llandovery to early Smith (1970), which crops out in Ludlow age (Hamilton-Smith 1970, the Siegas area of northwestern Roy and Mencher 1976). New Brunswick (Fig. 1). The for Fragmentary brachiopod faunas mation occurs within a (now) rela recognized by Ayrton et at. (1969) tively narrow northeast-southwest have indicated an early Llandovery elongate trough which extends from age for the Siegas Formation. Gaspe through New Brunswick and into Maine and termed the Central SEDIMENTOLOGY AND DEPOSITIONAL ENVIRONMENT The sedimentology and depositional environment of the Siegas Formation has been studied in de tail and succinctly described in a series of papers by Hamilton- Smith (1971a, 1971b, 1980). This section presented below therefore summarizes the major conclusions of Hamilton-Smith together with observations made by the present author. In view of the purpose of this paper, only a brief sum mation will be presented here, and the interested reader is re ferred to the above papers for a more detailed appraisal and for detailed geological maps of the area. Detailed mapping of the Siegas west New Brunswick and northeast Maine. area by Hamilton-Smith (1970) de- MARITIME SEDIMENTS AND ATLANTIC GEOLOGY 39 monstrated that in the north and erosive (a maximum of 2 m having northwestern part of the area the been observed), normally graded Siegas Formation was erosive into and/or imbricated and contain the underlying Carys Mills Forma- clasts up to 80 cm in diameter. tion. The depth of erosion was In others, the preferred clast estimated to be in the order of orientation is essentially paral- between 25-50 m, i.e. comparable lel to bedding, similar to those to known erosional depths of many recently described by Keith and present day small submarine can- Friedman (1977) from canyon and yon systems (see Shepard and Dill slope channelized and, or, sheet 1966, Whitaker 1976, etc.), and flow deposits from the Cambrian much larger than reported modern of New York and Vermont. and ancient inner and middle fan channels (see Walker and Mutti The graded and imbricated varie- 1973). This, combined with a ties are interpreted as the pro- detailed sedimentological apprai- duct of deposition from turbulent sal, led Hamilton-Smith (1971b) flows (turbidity currents) whereas to suggest that in the north and the other varieties were probably northwestern part of the area, produced by various forms of mass the Siegas Formation represented flow, such as debris flow or from a submarine canyon-fill. Indeed, incoherent slumping to a complex the absence of thinning and fin- sliding of relatively coherent ing upward sequences and thicken- lenticules one over another\with ing and coarsening upward sequen- most of the shear stress concen- ces, characteristic of mid-fan trated near lenticule margins and suprafan lobes respectively, Hamilton-Smith 1980). Conglomer- combined with the nature of the ates resembling those described sediments, do suggest deposition briefly here have been mentioned in an extremely 'proximal' environ- in the literature quite exten- ment comparable to many modern- sively (see Walker and Mutti 1973 day and ancient submarine canyon and Walker 1975 for a review) and systems (see Middleton and Bouma are considered by the majority of 1975, Whitaker 1976, Stanley and authors to be characteristic of Kelling 1978 and Doyle and Pilkey submarine canyon or inner fan 1979). channel deposits. This lithofacies association constitutes some 13% of the succession (Hamilton-Smith Although it is difficult to 1970). generalize on the nature of these (ii) Medium - coarse sandstones sediments, particularly as there up to 2.75 m in thickness and are demonstrable proximal-distal dominated by varieties exhibiting relationships across the entire complete and/or partial Bouma studied area, the canyon - fill sequences. These sandstones ex- strata or the ' lithic wacke facies ' hibit a variety of sole features of Hamilton-Smith (1970) exhibit including ripples, flutes, tools, the following characteristics. loads and gutter casts and are (i) Organized and disorganized typically graded. Convolute lami- matrix-supported conglomerates up nation is also commonly developed. to 8.5 m in thickness. Clasts are They are clearly a product of dominantly of limestone but also deposition by turbidity currents include slate, chert and mafic in a 'proximal' regime. Other volcanics, and the matrix is gen- sandstones are massive, internally erally mud and/or fine silt. Many structureless, and contain outsize of the organized conglomerates are pebble and cobble carbonate clasts 40 R.K. PICKERILL randomly distributed throughout. and northwest (Hamilton-Smith Since there are no fluid escape 1971a), whereas the coeval Carys structures the origin of these Mills Formation, into which the beds may possibly be explained by former is erosive, was, in the several processes: (i) deposition immediate area, derived from the under upper flow regime, (ii) northeast. The Carys Mills For- shearing by loosely compacted mation has been recently inter- sediment, (iii) deposition by a preted by Stringer and Pickerill rapidly decelerating current that (1980) and Rast and Pickerill (in failed to produce an equilibrium preparation) as a succession of bedform (cf. McCabe 1978), (iv) contourites deposited by deep fluidized sediment flow, (v) late thermohaline currents on a slope stage fluidization during deposi- which paralleled the ancient basin tion of a turbidity current de- margin. The Siegas Formation is posit. Irrespective of their therefore a deep channel or sub- origin, they are still considered marine canyon which is cut approxi- by other authors (e.g. Keith and mately perpendicular into the Friedman 1977) to be indicative slope succession of the Carys of 'proximal' environments. The Mills Formation. sandstone lithofacies constitute some 72 % of the succession The canyon-fill strata are, un- (Hamilton-Smith 1970). fortunately, generally poorly exposed, though an excellent and (iii) The remaining 15% of the almost completely exposed sequence succession is composed of thinly is present in the Siegas Quarry bedded laminated and cross-lami- (EMH 558 of Hamilton-Smith 1970). nated small-scale micaceous 4nd Here approximately 2 30m of strata calcareous siltstones and shales are continuously exposed and it with minor carbonates and cherts. is from here that the majority of These beds probably represent the trace fossils described herein end products of material reworked were located. Exposures else- by normal bottom currents within where are essentially 2-dimen- the canyon and deposition of pel- sional and somewhat inadequate agic and hemipelagic material car- for the purpose of detailed ichno- ried into deeper water by contour logical analysis. currents, nepheloid layers and, or, dilute turbidity currents. SYSTEMATIC DESCRIPTIONS Both processes are active in many modern submarine canyons (see For ease of reference, trace Stanley and Kelling 1978) and fossils in the Siegas Formation produce similar lithofacies. It are described alphabetically (cf. is within these sediments that,, Hahtzschel 1975) rather than etho- logically (cf. Chamberlain 1971) . in fact, Hamilton-Smith (1970) In terms of relative abundance made reference to the "obscure the following format has been trails" described in detail in adopted: Abundant -= >50 specimens this paper. recorded, Common = 30-50 speci- Further evidence that the ' lithic mens recorded, Frequent = 10-30 wacke facies' of Hamilton-Smith specimens recorded and Rare = <10 (1970) represents a submarine can- specimens recorded. Representa- yon-fill is afforded by a more tive examples of specimens des- regional and paleocurrent analy- cribed and illustrated in this sis of the Siegas Formation and paper are housed in the Depart- coeval strata. The Siegas Forma- ment of Geology, University of tion was derived from the north New Brunswick. MARITIME SEDIMENTS AND ATLANTIC GEOLOGY 41

Ichnogenus Buthotrephis Hall, 1847 (1847, 1952) specimens of Palaeo- phycus exhibit longitudinal stri- Buthotrephis sp. ations, whereas Buthotrephis is (Fig. 2d, 2e) more typically smooth. As the Siegas material is irregularly Description; Irregularly branched branched and has smooth walls, it cylindrical or subcylindrical bur- is therefore diagnosed as Butho- rows, parallel or slightly oblique trephis, but in view of the confu- to stratification and typically sion, only at ichnogeneric level. preserved on upper and lower surfaces of shales, calcareous shales Buthotrephis is a facies cross- and siltstones. Individual bur- ing ichnogenus, Cambrian - Recent rows may be up to 8 mm in diameter in age, and probably represents but are commonly smaller (mean the feeding burrow of an infaunal 4 mm), posses smooth walls and a polychaete annelid (Ksiazkiewicz burrow fill which is typically of 1977). identical grain size to the enclosing sediment. The trace may Ichnogenus Chondrites be distinguished from the mor- von Sternberg, 18 33 phologically similar ichnogenus Chondrite s by its non-systematic Chondrites sp. branching patterns. (Fig* 2g) Associated forms; Gordia, Helmin- Description: Plantlike dendritic thopsis, Neonere.ites patterns of small burrows, indi- Relative abundance: Abundant vidual tunnels neither crossing nor intersecting. Burrow diameter Discussion: There still exists ranges from 4-8 mm but is consis- considerable confusion in the tent within individual specimens. literature regarding the defini- The burrows are generally observed tion and differentiation of the parallel to stratification on both irregularly branched burrows of upper and lower surfaces of shales, Buthotrephis and Palaeophycus and 3 calcareous shales and siltstones. a restudy of both is necessary. Two and three orders of branching, Although most of Hall's (1847) generally in regular pinnate or original specimens of Buthotre- variable patterns, may be obser- phis are undoubtedly chondritids ved. Branching angles vary, even (Hantzschel 1975, Ksiazkiewicz within individual specimens, from 1977) some of them (e.g. B. pal- between 2 0-50°. mata and B. suceulens) cannot be justifiably assigned to Chond- Associated forms: Gordia, Helmin- rites. B. palmata may in fact thopsis3 Planolites, Eeonereites belong to the ichnogenus Phycodes Richter, 1850 but a restudy of Relative abundance: Abundant Hall's material is necessary to Discussion: The facies crossing resolve this. Similarly, Palaeo- ichnogenus Chondrites 3 which ran- phycus is also a poorly defined ges in age from Cambrian-Recent, ichnogenus, with some authors is an extremely variable form. (e.g. Osgood 19 70, Chamberlain Many ichnospecies of the trace 1977) assigning only unbranched purportedly exist (e.g. Chamber- or sparsely branched forms, and lain 1977), the majority subjec- others (e.g.Alpert 1975,Pickerill tively based on variations in and Forbes 19 79) assigning irregu- size, preservation and angle of larly branched forms to this ich- branching. In view of the gene- nogenus. The majority of Hall's rally poor preservation of the 42 R.K. PICKERILL

Siegas material and the unsatis- sible to ascertain with the Siegas factory taxonomic status of the material, as diagenesis has masked ichnogenus, it is here only iden- its former nature. For this rea- tified at ichnogeneric level. son, the material is included within the ichnospecies C. angui- Chondrites is normally regarded neus, as Hitchcock (1958) des- as a feeding burrow of sipunculid cribed the trace as a 'trackway' annelids (Simpson 1947), tiny and not a burrow. arthropods (Ekdale 19 77) or unknown tentacle-bearing organisms Ichnogenus Diplichnites Dawson, 1873 (Taylor 1967). Diplichnites sp.

Ichnogenus Cochlichnus (Fig. 2h, 5f) Hitchcock, 1858 Description: Paired rows of small Cochlichnus anguineus Hitchcock, 1858 dot-like or slightly elongate (Fig. 2c) (normal to the trace axis) imprints, approximately 1 mm in di- Description; Small, regularly sin- ameter. In rare examples the im- usoidal traces, parallel to stra- prints assume an- obtuse V-shape tification and commonly preserved rather than simply being elongate. in convex hyporelief and more The pairs of imprints remain sep- rarely in concave epirelief. arated and evenly spaced through- Specimens are generally 1mm in out the length of the trace. The diameter, up to 70mm in length and width of an individual set is 4-6 smooth throughout their extent. mm. Dactyl impressions are absent. Occasionally a slight thickening may be observed at the apices of Associated forms: Cochlichnus, the meanders. Gordia Associated forms: Diplichnites, Relative abundance: Frequent Gordia, ftleonereite s Discussion: Diplichnites is a mor- Relative abundance: Frequent phologically simple trace and is usually interpreted as the walk- Discussion: The ichnogenus Coch- ing track of a trilobite (Crimes lichnus is a facies crossing form, etal., 1977). It has been report- having previously been described ed in rocks of Cambrian-Permian from a wide range of palaeoenvi- age (Hantzschel 1975) and is re- ronments of late Precambrian-Ter- garded as a typical shallow water tiary age. It is generally re- (neritic) form (e.g. Crimes, garded to have been produced by 1975). The recording by Pickerill nematodes or annelids lacking (1980) and this example here now well-developed parapodia (Michelau extend its environmental distri- 1956, Hakes 1976). The trace may bution to deeper water strata. represent a true burrow, as in the Although the preservation of the case of Cochlichnus serpens (see Siegas material is not suffici- Webby 1970), but this is impos- ently good for ichnospecific iden-

Fig. 2 a. Skolithos sp. in thinly bedded, parallel laminated calcareous silts and shales, b. Helminthopsis cf. abeli on sole of turbiditic sandstone, c. Cochlichnus aniguineus on sole of laminated siltstone. d. Gordia sp. in association with small Buthotrephis sp. on sole of calcareous shale, e. Buthotrephis sp. on upper surface of parallel laminated calcareous siltstone. f. Scalarituba missouriensis on upper surface of calcareous shale, g. Chondrites sp. on sole of parallel laminated calcareous shale, h. Diplichnites sp. on side of parallel laminated siltstone. Bar scale = 1 cm.

44 R.K. PICKERILL tification, the specimens closely ently reflecting the burrowing resemble Osgood and Drennen's activity of its producer. (1975) Type A Dipliohnite s from the Silurian Clinton Group of New Ichnogenus Gordia Emmons, 1844 York State. Gordia axcuata Ksiazkiewicz, 1977 (Fig. 3b) Ichnogenus Fuousopsis Palibin in Vassoevich, 1932 Description: Thin, thread-sized Fuousopsis sp. burrows preserved in convex hypo- (Fig. 5b) relief and all assuming an incom plete loop-like (arcuate) form. Description; Straight to slightly The burrow diameter is 1 mm and curved, longitudinally striated the surface is always smooth. The cylindrical burrows up to 12mm burrow fill is typically of iden in length that are unbranched and tical grain size as the enclosing parallel to stratification. The sediment. Specimens may be dif burrows are clearly post-deposi- ferentiated from the morphologi tional in origin, up to 10 mm in cally similar trace Furouiosus diameter and may occur as solitary specimens or in groups on the same bedding plane. The most common mode of preservation is in convex hyporelief and the burrow fill is typically of the same grain size and, or, slightly coarser than the enclosing sediment. Associated forms: Chondrites3 Gordia, Helminthopsis3 Planolites Relative abundance: Frequent Discussion: Though a number of ichnospecies of Fuousopsis have been described (see Ksiazkiewicz 1977), the Siegas material is not well enough preserved for ichnospecific assignment. Furthermore, some specimens are apparently in termediate between F. an g.u la.ta Palibin, 1932, where the longi tudinal striations are discon tinuous, and F. stria ta Hall, 1852 , where the striations are continu ous and more closely spaced. In view of this, the material is only identified at ichnogeneric level. Fuousopsis is a well documented facies crossing form ranging in age from Ordovician-Oligocene, and represents the feeding burrow of Fig. 3 - Field photographs of Gordia sp. an infaunal organism (? annelid), (a) and Gordia arouata (b) on upper sur the ridge-like sculptures, accord face of calcareous shales. Pen tip = 9 ing to Seilacher (1959), appar mm. MARITIME SEDIMENTS AND ATLANTIC GEOLOGY 45 eax>pathieus Roniewicz and Pien- (1977), probably represents the kowski, 1977 by their more arcuate post-depositional feeding burrow shape and smaller burrow diameter. of a polychaete annelid.

Gordia sp. Ichnogenus Gyrochorte Heer, 1865 (Fig. 2d, 3a) Gyrochorte sp. (Fig. 5e) Description: Slender thin burrows preserved in convex hyporelief Description: Cylindrical or sub- and convex/concave epirelief which cylindrical bilobate burrows of wind and curve non-systematically post-depositional origin and up to and cross-cut in an irregular man- 15 mm in diameter and a maximum ner. The burrows are smooth and observed length of 12 3 mm. The up to 2 mm in diameter. The bur- burrows are straight to slightly row fill is typically of identical curved and are characterized by grain size as the enclosing sedi- the development of a distinctive ment. The traces can be differ- obliquely transverse, densely entiated from the morphologically spaced but irregular, biserial similar trace Helminthopsis in surface ornament, consisting of that they commonly cross-cut one incisions which join in/a medium another. and generally shallow apical groove. The burrow fill is typically of Associated forms: Buthotrephis, silt grade whereas the burrows Chondrites, Cochlichnus, Diplich- cut thinly laminated silts and nites, Fucusopsis, Helminthopsis, shales. They are commonly pre- Neonereites served in convex epirelief, though hyporelief preservation has been Relative abundance: Gordia arcu- rarely observed. ata - Rare, Gordia - Abundant Associated forms: Unknown Discussion: Gordia arcuata, recently described from flysch of Relative abundance: Frequent the Polish Carpathians by Ksiaz- kiewicz (1977), is a rare form in Discussion: A number of ichno- the Siegas Formation but can be species of Gyrochorte have been clearly distinguished by its dis- described in the literature (see tinctive morphology. The second Hallam 1970, Hantzschel 1975, form, however, resembles both the Ksiafckiewicz 1977) but the Siegas type specimen G. marina as for 3 material is not well enough pre- example recently figured by Cham- served and, or sufficiently abun- berlain (1977), and G. molassica dant to warrant formal ichno- as described by Heer (1865). The specific identification. It is latter may, in fact, prove to be also apparent that the criteria a junior synonym of G. marina, as presently adopted for ichnospeci- the two ichnospecies appear to be fic separation of Gyrochorte are identical. Until the detailed somewhat subjective and therefore synonymy is resolved, the Siegas at this time the present author material is only identified at prefers an ichnogeneric assign- ichnogeneric level. ment. Nevertheless, the traces Gordia is a facies crossing ich- do resemble G. obiterata Ksiaz- nogenus of late Precambrian-Oligo- kiewicz, 1977 in that the median cene age and, according to Ksiaz- groove is shallow and the oblique kiewicz (1977) and Chamberlain incisions are irregular and dense- 46 R.K. PICKERILL ly spaced, but differs from this occurrence was in association with ichnospecies in that the ribbing outer fan and basin plain envi- is usually well-developed. The ronments. The recording here thus Siegas material is wider than G. extends its environmental range cosmosa Heer, 1865 and G. imbri- to submarine canyons. cata KsiaSkiewicz 1977, but nar- Eelminthoida has been recorded rower than G. burtani Ksiazkiewicz, from Ordovician-Oligocene strata 1977. and is normally regarded as the grazing product of worm-like or- Gyrochorte is 'normally' regarded ganisms, presumeably polychetes as a shallow water neritic form (Ksiazkiewicz 1977). (e.g. Seilacher 1978) though deep water recordings have also been made (e.g. Ksiazkiewicz 1977, Ichnogenus Helminthopsis Heer, 1877 Pickerill 1980). It ranges in age Helminthopsis of. albeli from Ordovician-Oligocene and was Ksiazkiewicz, 1977 most probably produced by the bur- (Fig. 2b). rowing activity of small amphipods (Abel 19 35) or annelids (Heinberg Description: Irregularly and 1973). loosely winding or meandering unbranched burrows, parallel and, Ichnogenus Helminthoida or, sub-parallel to stratifica- Schafhautl, 1851 tion, and usually preserved in Helminthoida labyvinthica Heer, 1865 convex hyporelief, rarely in con- (Fig. 5c, 5d) cave epirelief. Burrow diameter ranges between 3-7 mm but is con- Description; Tightly spaced, reg- sistent for a single specimen. ularly and parallel meandering The burrows are cylindrical and, burrow system, the burrow width or subcylindrical, smooth through- being 5-6 mm, separated from ad- out their extent and in contrast jacent meanders by 1-2 mm of sedi- to the related ichnogenus Gordia, ment. Individual meanders are never intersect. The winding or curved and occasionally even coil- meandering path is extremely vari- ed. Typically, an individual me- able and non-systematic. Speci- ander is 4-5 cm high. The trace mens are preserved in shales, is generally poorly preserved and calcareous shales and, or, silt- has only been observed in float stones. material in calcareous siltstones. Associated forms: Buthotrephis, Associated forms; Neoneveites Chondrites3 Fuousopsis3 Gordia, Neonereites3 Planolites Relative abundance: Rare Relative abundance: Abundant Discussion: Helminthoida is a characteristic deep water trace Discussion: Based on the para- fossil, usually associated with meters presently adopted for ich- the Neveites ichnofacies of nospecific assignment of Helmin- Seilacher (1967). Although H. thopsisj viz:- the nature and labyvinthica is commonly regarded type of winding, the burrow dia- as a Mesozoic form (Hantzschel meter and the presence or absence 1975), it has recently been re- of surface ornamentation (Ksiaz- corded (Pickerill 1980, Fig. 3c) kiewicz 1977), a number of ichno- from Ordovician strata. Crimes species have been proposed. How- (1977) noted that its most common ever, the Siegas material exhibits MARITIME SEDIMENTS AND ATLANTIC GEOLOGY 47

ISi?

1 0\ yft iipii^ %

Fig. 4 Variation in Neonereites spp. from the Siegas Formation; a illustrates both N. imiserialis and N. biserialis (upper right), b and c show N. imiserialis and d shows N. imiserialis progressing in to N. biserialis. All specimens are sole structures preserved in calcareous shales. Bar scale = 1 cm. variable winding and meandering view of the considerable varia- patterns within a single specimen tion, however, it is deemed that and different burrow diameters may previously adopted ichnospecific exhibit the same or different be- criteria are perhaps unsatisfac- havioural patterns. Nevertheless, tory and are in need of careful the material is closely compar- reassessment. able, both in terms of burrow dia- Helminthopsis is a facies cross- meter and the variable and loosely ing form, though more commonly re- winding and meandering patterns, ported from deep water succes- to Helminthopsis abeli and is sions. It ranges in age from tentatively diagnosed-as such. In Cambrian-Oligocene and is regard- 48 R.K. PICKERILL

Fig. 5 - a Protopaleodictyon sp. on sole of current fluted (top left to bottom right) turbidite sandstone, b. Fucusopsis sp. on sole of turbiditic sandstone, c-d. Eelminthoida labyrinthica on upper surface of parallel laminated calcareous shale. Note the poor preservation, e. Gyrochorte sp. on sole of calcareous siltstone. f. Diplichnites sp. on sole of parallel laminated siltstone. g. Planolites beverleyensis on sole of parallel and cross laminated calcareous siltstone. Bar scale = 1 cm. MARITIME SEDIMENTS AND ATLANTIC GEOLOGY 49

ed as having been produced by Chondrites, Gordia, Helminthoidas polychete annelids (Ksiazkiewicz Helminthopsis, Planolites 1977). Relative abundance: N. uniseri- Ichnogenus Neonereites alis - abundant, N. biserialis - Seilacher, 1960 common. Neonereites uniserialis Discussion: Neonereites is a fa- Seilacher, 1960 cies crossing ichnogenus, probably representing the fodinichnia of (Fig. 4) infaunal annelids (Hakes 1976) and has been recorded from strata Description: Sinuous or curved of late Precambrian-Tertiary age chains of closely spaced rows of (Hantzschel 1975, Fedonkin 1977). uniserially arranged subcircular Seilacher and Meischner (1964) to oblong knobs preserved in con- grouped Neonereites with the ich- vex hyporelief. The long axis of nogenera Nereites and Soalarituba individual knobs is normal to the but not as strict synonyms, but chain "length and varies in size later Chamberlain (1971) regarded from 1-4 mm. Individual chains, Nereites and Neonereites as preser- however, are composed of knobs of vational variants of Soalarituba. the same size. In general, adja- Subsequent authors, however, again cent knobs do not come into con- separated these three related ich- tact, though the gap is extremely nogenera (e.g. Hantzschel 1975, small, commonly <1 mm. The chain Hakes 1976, Brasier and Hewitt shape and length exhibit consider- 1979). In view of their distinc- able variation - some are sine- tive morphology and the absence like and up to a length of 300mm, of Soalarituba - like and, or, some are horseshoe-shaped but the Nereites - like preservation (as majority are irregular. Occasion- recorded by careful sectioning of ally the trace is preserved in the traces), Neonereites is also concave epirelief as a series of regarded here as a separate and closely spaced depressions. distinctive ichnogenus. Although the two distinctive Neonereites biserialis Seilacher, 1960ichnospecie s N. uniserialis and (Fig. 4) N. biserialis are generally easily separated, occasional specimens from the Siegas Formation exhibit Description: In contrast to N. transitional forms with one pass- uniserialis Neonereites biserial- s ing directly into the other (Fig. is, the type species of the ichno- 4d), thus providing yet a further genus, consists of chains of two example of the persistent nomen- closely spaced rows of subcircular clatural difficulties faced by knobs preserved in convex hypore- ichnologists {of. Bromley and lief. Knobs of adjacent rows are Frey 1974, Frey and Seilacher not opposite but alternate in 1980). position. As with N. uniserialis 3 the chain shape, length and width Ichnogenus Planolites vary considerably, though the Nicholson, 1873 latter is again consistent within Planolites beverleyensis an individual specimen. The trace Billings, 1862 is only rarely preserved in concave epirelief. (Fig. 5g)

Associated forms: Buthotrephis, Description: Unbranched, smooth- 50 R.K. PICKERILL walled cylindrical, subcylindri- Protopaleodiotyon sp. cal and flattened sediment filled (Fig. 5a) burrows, generally parallel and rarely sub-parallel to stratifi- Description: Thread-like, incom- cation. The burrows are straight plete network burrow system, 2 mm or only slightly curved, thus in width and smooth throughout distinguishing them from the mor- their length. Each system con- phologically similar trace Helmin- sists of wide first order mean- thopsis which is characterized 3 ders upon which are superimposed by loose winding and, or, mean- smaller second order sine-shaped dering patterns. The sediment undulations with distinct appen- fill may be coarser, finer or of dages. The trace is horizontal identical grain size to the enclosing sediment, which is com- and preserved on the sole of cur- monly calcareous siltstone. The rent fluted turbidite sandstones. burrow diameter varies from 3-12 mm and is typically consistent Associated forms: Planolites within an individual trace. Relative abundance: Rare Associated forms: Chondrites 3 Discussion: There is still no Fuaosopsis Helminthopsis Neo- 3 3 general agreement on what con- nereites Protopaleodiotyon. 3 stitutes a distinctive ichnospecies of the graphoglyptid trace Relative abundance: Abundant Protopaleodiotyon3 with Seilacher (1977) utilizing the number of Discussion: Planolites is a facies branches/undulation and Ksiaz- crossing ichnogenus ranging in kiewicz (1977) the regularity and age from late Precambrian-Recent spacing of the first order mean- (Hantzschel 1975) and commonly ders and the size and thickness attributed to the burrowing acti- of the strings. In view of this vity of annelids (Hallam 1970). inconsistency, the Siegas material It is similar to Palaeophyaus is only identified at ichnogeneric Hall, 1847 and the distinction level. Protopaleodiotyon is a between these two ichnogenera deep water trace fossil character- still remains controversial. Fol- istic of the Nereites ichnofacies lowing Hantzschel (1975), Alpert of Seilacher (1967). It ranges (1975) and McCarthy (1979), how- in age from Ordovician-Tertiary ever, Palaeophyaus is only avail- and was presumeably constructed able for irregularly branched by some unknown infaunal annelid. burrows. Furthermore, Palaeo- phyaus burrows also commonly pos- Ichnogenus Soalarituba Weller, 1899 sess irregular walls which often Soalarituba missouriensis display collapse structures (Frey Weller, 1899 and Chowns 1972). The Siegas material is therefore diagnosed (Fig. 2f) as Planolites. The taxonomy of Description: Straight, curved or Planolites has been recently re- winding traces preserved in con- viewed by Alpert (1975) and the cave epirelief and up to 6 mm in Siegas material is identical to P. width and variable length. Each beverleyensis. trace is characterized by closely spaced crescentric partitions which Ichnogenus Protopaleodiotyon are transversely oriented and dis- Ksiazkiewicz, 1970 tinguishable by slight colour MARITIME SEDIMENTS AND ATLANTIC GEOLOGY 51

variation from one to the next. abundant specimens is usually The traces are preserved in dark indicative of a shallow marine shales and have only been observed environment (Seilacher 1967) in float material. though deep water recordings have also been made (e.g. Hayward 1976, Associated forms: Unknown Crimes 19 77). The Siegas material also resembles Tigillites Rouault, Relative abundance: Frequent 1950, which is usually reserved for noncrowded vertical burrows. Discussion: Soalarituba is amono- However, burrow density is regard- typic ichnogenus and has been ed as a palaeoecological variable previously reported from envi- and should not be utilized in ronments ranging from tidal flat taxonomic decisions. Tigillites (Conkin and Conkin 1968) to deep is therefore regarded as a junior water flysch (Seilacher and Meis- synonym of Skolithos. Because of chner 1965, Chamberlain 1971, the unsatisfactory taxonomic sta- Pickerill 1980). It ranges in tus of the trace at the present age from Ordovician-Permian and time, the specimens are only iden- represents the activity of worms tified at ichnogeneric level. burrowing within the sediment and episodically back-filling the bur- DISCUSSION rows, thereby creating the transverse partitions (Hakes 1976). It must be emphasized that the trace fossils described in this paper are from strata deposited Ichnogenus Skolithos Haldeman, 1840 within the canyon and not the can- Skolithos sp. yon walls. The latter are generally poorly exposed in the Siegas (Fig. 2a) area, and where present (see Hamilton-Smith 1970), no trace Description: Smooth and unlined, fossils have been observed in as- vertical or slightly oblique, sociation with them. It must cylindrical or subcylindrical, also be noted that the traces unbranched burrows which fre- generally occur in sediments of quently possess irregular walls. category (iii) as outlined pre- The burrows may be isolated or viously, or, alternatively, as clustered but never densely sole structures on the base of crowded. Burrow diameter ranges turbidites described under cate- up to an observed maximum of 8 mm. gory (ii). No trace fossils were Burrow fill is generally coarser observed in association with the than the enclosing sediment, which organized and disorganized resedi- is typically laminated calcareous mented conglomerates of category shale. (i) . Associated forms: Unknown, as the trace is only observed in verti- The majority of the variety of cal section. trace fossils described from the Siegas Formation, which are shown Relative abundance: Abundant schematically in Figure 6, are well-known facies crossing forms, Discussion: Skolithos is an ich- having been previously reported nogenus of late Precambrian-Recent from a variety of shallow and deep age and represents the dwelling water environments. These include burrow of annelids or phoronids Buthotrephis, Chondritess Cochli- (Alpert 1974). The presence of ohnus3 Fuousopsis, Gordia, Gyro- 52 R.K. PICKERILL

Buthotrephis SP. 2 Chondrites SP. 3 Cochhchnus anguineus 4 Diplichnites sp. 5 Fucusopsts SP. 6 Gordia arcuata 7 Gordia sp. 8 Gyrochorte sp. 9 Helminthoida iabyrinthica 10 Helminthopsis cf. abeli 11 Neonereites uniseria/is 12 Neonereites biserialis 13 Planolites bever/eyensis 14 Protopaleodictyon sp. 15 Scalarituba missouriensis 16 SkoHthos SP.

Fig. 6 - Schematic representation of the Siegas Formation submarine canyon ichno-assemblage. No scale is implied. ohorte3 Neonereites3 Planolites and 'Nereites 3 recently noted by and Soalarituba. The assemblage Stanley et al. (1978) from Eocene does, however, contain the typical canyon-fill strata of the French or more typical "shallow water" Maritime Alps. Unfortunately traces Skolithos and Dipliohnites Crimes {ibid.) does not mention and those commonly recorded in the which facies crossing ichnogenera Nereites ichnofacies of Seilacher are likely to be present in sub- (1967) in middle fan, outer fan marine canyon sequences (with the and trough sediments, Helmintho- exception of Chondrites3 Neonerei- ida, Helminthopsis and Protopaleo- tes and Scolicia), but if the dictyon. Dipliohnites3 Helmin- Siegas material is representative, thoida3 Helminthopsis and Proto- the list is likely to be a rea- paleodictyon represent new trace sonably extensive one providing fossil recordings in submarine that the trace fossils are pre- canyon sequences (see Crimes 1977, served and not eroded by periodi- Table 4, p. 80), whereas, as men- cally powerful currents. tioned previously, Skolithos has The mutual occurrence of "shal- already been recorded. To this low" and "deep" traces in associ- list of new recordings must be ation with the facies crossing added Zoophyoos ( = Zoophyaus) variety suggests that substrate, MARITIME SEDIMENTS AND ATLANTIC GEOLOGY 53

food availability, temperature yons. Sedimentological consider- and/or ecological interactions tions would tend to confirm that rather than bathymetry per se this situation probably existed were important parameters regard- for the majority of time in the ing their presence (of. Crimes Siegas Formation, and currents 1970, Frey and Howard 1970). Con- only became periodically strong trary to the proposal by Crimes with the introduction of mass-flow (1977, p. 79) regarding ancient deposits. This is also suggested submarine canyon ichnofaunas, the by the good preservation of the assemblage is composed essenti- delicate traces produced at the ally of traces produced by vagile sediment-water interface, such as infaunal sediment eaters and gra- Biplichnites and Neonereites3which zers and does not include dwell- show no evidence of fluting by ing burrows. In fact, the 'anti- currents {of. Crimes 1973) or cipated' submarine canyon traces rheotactic orientation. The ab- of Crimes {ibid.) viz:- the sence of traces produced by filter dwelling burrows Arenioolites3 feeding organisms in the Siegas Corophioides3 Diplooraterion, Formation may therefore well be Monooraterion and Ophiomorpha and related (in addition to the po- Thalassinoides, are all absent. tential preservational difficul- The absence of Ophiomorpha and ties) to the absence of suffic- Thalassinoides is hardly surpri- iently strong bottom currents, sing, as these trace fossils have which, in turn, precluded the yet to be recorded in Lower Pala- presence of an active and abun- eozoic sediments (H&ntzschel 1975). dant suspension feeding popula- The absence of the additionally tion of organisms. Instead, the listed dwelling burrows, however, Siegas Formation is characterized cannot be reconciled stratigra- by traces produced by deposit phically, as all these traces feeders, particularly infaunal have been commonly observed and deposit feeders, thus suggesting recorded in many sequences of that the sediments contained suf- Lower Palaeozoic age. However, ficiently abundant organic detri- these ichnogenera are most com- tus to support such a population monly recorded in shallow water of organisms. environments, themselves characterized by active and medium-high Crimes (1977) also noted that velocity currents. Indeed, the submarine canyon environments presence of active bottom currents could probably only support an to provide sufficient organic ichnofauna of low abundance and material and water turbulence diversity. Nevertheless, and appears to have been particularly indeed as noted by Crimes himself, important regarding the occurrence data on submarine canyon environ- of these latter traces, which are ments is sparse. This particular all produced by filter feeding conclusion was based on the as- (? annelid) organisms. Crimes sumption that medium-coarse grain- {op. oit.), in fact, predicted ed sandy substrates swept by fast- their presence in submarine can- flowing currents could not support yon sequences for this very rea- a diverse population of organisms. son. As outlined above, however, cur- Nevertheless, recent observa- rent conditions are extremely var- tions by Shepard et al. (1979), iable and, in addition, modern can- have demonstrated that relatively yons are characterized by a vari- slow velocity currents can be com- ety of substrate types (Shepard monplace in modern submarine can- et al. 1979). This study has, in 54 R.K. PICKERILL fact, recorded a minimum of 14 brian, White-Inyo Mountains, Califor- ichnogenera (16 ichnospecies), nia. Journal of Paleontology, 49, pp. which according to the latest pro- 508-521. posed Phanerozoic trace fossil di- AYRTON, W.G., BERRY, W.B.N., BOUCOT, A. versity models (Frey and Seilacher J., LAJOIE, J., LESPERANCE, P.I., 1980), is diverse for deep water PAVLIDES, L. and SKIDMORE, W.B. 1969. strata of Silurian age. In addi- Lower Llandovery of the Northern Ap- tion, many of the traces can also plachians and Adjacent Regions. Bul- be termed abundant in the sense letin of the Geological Society of that over 50 specimens of each America, 80, pp. 459-484. were recorded over a large stratigraphic interval. BATES, R.L. and JACKSON, J.A., Editors In conclusion, therefore, this 1980. Glossary of Geology American example of an ancient submarine Geological Institute, Falls Church, canyon sequence has demonstrated Virginia, 2nd edition, 749p. that such strata may, in fact, BRASIER, M.D. and HEWITT, R.A. 1979. possess a wide variety of trace Environmental setting of fossiliferous fossils, comparable in many re- rocks from the uppermost Proterozoic- spects to other ancient deep sea lower Cambrian of central England. environments. Although data on Palaeogeo graphy, Palaeoclimatolo gy, ancient submarine canyon sequences Palaeoecology, 27, pp. 35-57. is still sparse, it is anticipated that as research is undertaken in BROMLEY, R.G. and FREY, R.W. 1974. Re- comparable sequences, similarly description of the trace fossil Gyro- diverse trace fossil assemblages lithes and taxonomic evaluation of will be revealed. Only with the Thalassinoides, Ophiomorpha and Spon- careful collection and descrip- geliomorpha. Bulletin of the Geologi- tion of trace fossil material will cal Society of Denmark, 23, pp. 311- meaningful and realistic models 335. of submarine canyon ichnocoenoses through time be realized. CHAMBERLAIN, C.K. 1971. Morphology and ethology of trace fossils from the ACKNOWLEDGEMENTS Ouachita Mountains, southeast Okla- homa. Journal of Paleontology, 45, pp. I wish to thank Drs. T. Harland 212-246. and W. Forbes for their critical reviews of the original manuscript 1977. Ordovician and and S. Townsend, G. Landry and R. Devonian trace fossils from Nevada. McCulloch for their technical as- Nevada Bureau of Mines and Geology, sistance during its preparation. Bulletin 90, 24p. D. Fillion provided the French CONKIN, J.E. and CONKIN, B.M. 1969. translation of the abstract. This Soalarituba missouriensis and its work was undertaken during the stratigraphic distribution. University tenure of N.S.E.R.C. Grant A3857 of Kansas Paleontological Contribu- which is gratefully acknowledged. tions, Paper 31, 7p.

ABEL, 0. 1935. Vortzeitliche Lebens- CRIMES, T.P. 1970. The significance of spuren. Gustav Fischer (Jena), 644p. trace fossils in sedimentology, stratigraphy and palaeoecology with exam- ALPERT, S. 1974. Systematic review of the genus Skolithos. Journal of Pale- ples from Lower Palaeozoic strata. In ontology, 48, pp. 661-669. Trace fossils. Edited by T.P. Crimes and J. C. Harper. Geological Journal 1975. Planolites and Skolc&thos Special Issue Number 3, Seel House from the Upper Precambrian-Lower Cam- Press, Liverpool, pp. 101-126. MARITIME SEDIMENTS AND ATLANTIC GEOLOGY 55

1973. From limestones to parison of Upper Cretaceous ichno- distal turbidites: a facies and trace faunas from siliceous sandstones and fossil analysis in the Zumaya flysch chalk, Western Interior Region,U.S.A. (Paleocene-Eocene), North Spain. Sedi- In Trace fossils. Edited by T.P. Crimes mentology, 20, pp. 105-131. and J.C. Harper. Geological Journal Special Issue Number 3, Seel House 1975. The stratigraphical Press, Liverpool, pp. 141-166. significance of trace fossils. In The Study of Trace Fossils. Edited by R.W. FREY, R.W. and CHOWNS, T.M. 1972. Trace Frey. Springer-Verlag, Berlin, Heidel- fossils from the Ringgold road cut berg, New York, pp. 109-130. (Ordovician and Silurian). Georgia. In Sedimentary environments in the 1977. Trace fossils of an Paleozoic rocks of northwest Georgia. Eocene deep-sea sand fan, northern Compiled by T. M. Chowns. Geological Spain. In Trace fossils 2. Edited by Survey of Georgia Guidebook 11, pp. T.P. Crimes and J.C. Harper. Geolo- 25-55. gical Journal Special Issue Number 9, Seel House Press, Liverpool, pp. 71- FREY, R.W. and SEILACHER, A. 1980. Uni- 90. formity in marine invertebrate ichnology. Lethaia, 13, pp. 183-207. CRIMES, T.P., LEGG, I., MARCOS, A. and ARBOLEYA, M. 1977. ? Late Precambrian- HAKES, W.G. 1976. Trace fossils and de- low Lower Cambrian trace fossils from positional environment of four clas- Spain. In Trace Fossils 2. Edited by tic units, Upper Pennsylvanian mega- T.P. Crimes and J.C. Harper. Geologi- clothems, northeastern Kansas. Uni- cal Journal Special Issue Number 9, versity of Kansas Paleontological Con- Seel House Press, Liverpool, pp. 91- tributions, Article 63, 46p. 138. HALL, J. 1847. Paleontology of New York. DILLON, W.P. and ZIMMERMAN, H.B. 1970. State of New York (Albany, N.Y.), Erosion by biological activity in two volume 1, 338p. New England submarine canyons. Journal 1852. Paleontology of New York. of Sedimentary Petrology, 40, pp. 542- State of New York (Albany, N.Y.), 547. volume 2, 362p. DOYLE, L.J. and PILKEY, O.H., Editors. HALLAM, A. 1970. Gyroohorte and other 1979. Geology of Continental Slopes. trace fossils in the Forest Marble Society of Economic Paleontologists (Bathonian) of Dorset, England. In and Mineralogists Special Publication Trace fossils. Edited by T.P. Crimes Number 27, 374p. and J.C. Harper. Geological Journal EKDALE, A.A. 1979. Abyssal trace fos- Special Issue Number 3, Seel House sils in worldwide Deep Sea Drilling Press, Liverpool, pp. 189-200. Project cores. In Trace fossils 2. HAMILTON-SMITH, T. 1970. Stratigraphy Edited by T.P. Crimes and J.C. Harper. and structure of Ordovician and Silu- Geological Journal Special Issue Num- rian rocks of the Siegas area, New ber 9, Seel House Press, Liverpool, Brunswick. Mineral Resources Branch, pp. 163-182. Department of Natural Resources, New FEDONKIN, M.A. 1977. Precambrian-Cam- Brunswick, Report of Investigation brian ichnocoenoses of the east Euro- No. 12, 55p. pean platform. In Trace fossils 2. 1971a Paleogeography Edited by T.P. Crimes and J.C. Harper. of northwestern New Brunswick during Geological Journal Special Issue Num- the Llandovery, a. study of the pro- ber 9, Seel House Press, Liverpool, venance of the Siegas Formation. Cana- pp. 183-194. dian Journal of Earth Sciences, 8, pp. FREY, R.W. and HOWARD, J.D. 1970. Com- 196-203. 56 R.K. PICKERILL

1971b. A proximal-distal McCABE, P.J. 1978. The Kinderscoutian turbidite sequence and a probable sub- Delta (Carboniferous) of Northern marine canyon in the Siegas Formation England: A Slope Influenced by Den- (Early Llandovery) of northwestern sity Currents. In Sedimentation in New Brunswick. Journal of Sedimentary Submarine Canyons, Fans, and Trenches. Petrology, 41, pp. 752-762. Edited by D.J. Stanley and G. Kelling. Dowden, Hutchinson and Ross Incorpor- 1980. Stratigraphy and ated, pp. 116-126. sedimentology of the Siegas Formation (Early Llandovery) of northwestern MCCARTHY, B. 1979. Trace fossils from a New Brunswick. In A guidebook to the Permian shoreface-foreshore environ- geology of northeastern Maine and ment, eastern Australia. Journal of neighboring New Brunswick. Edited by Paleontology, 53, pp. 345-366. D.C. Roy and R.S. Naylor. 72nd Annual MICHELAU, P. 1956. Belorhccphe hoohi Meeting of the New England Inter- (Ludwig 1869), eine Wurmspur im euro- collegiate Geological Conference, Bos- paischen Karbon. Geologische Jahr- ton College Press, pp. 202-211. buch, 71, pp. 299-330. HANTZSCHEL, W. 1975. Trace fossils and MIDDLETON, G.V. and BOUMA, A.H.., Editors. problematica. In Treatise on inverte- 1975. Turbidites and Deep-Water Sedi- brate Paleontology, Part W. Miscel- mentation. Society of Economic Pale- lanea. Edited by C. Teichert. Univer- ontologists and Mineralogists, Short sity of Kansas Press and Geological Course, Anaheim, 157p. Society of America, Lawrence, KS, pp. W1-W296. OSGOOD, R.G. 1970. Trace fossils of the Cincinnati area. Paleontographica HAYWARD, B.W. 1976. Lower Miocene bathyal Americana, 5, pp. 282-444. and submarine canyon ichnocoenoses from Northland; New Zealand. Lethaia, OSGOOD, R.G. and DRENNEN, W.T. 1975. 9, pp. 149-162. Trilobite trace fossils from the Clin- ton Group (Silurian) of east-central HEER, 0. 1865. Die Urwelt der Schweiz. New York State. Bulletins of American Zurich, 622p. Paleontology, 67, pp. 299-348. HEEZEN, B.C. and HOLLISTER, C.D. 1971. PICKERILL, R.K. 1980. Phanerozoic flysch The Face of the Deep. Oxford Univer- trace fossil diversity - observations sity Press Incorporated, 659p. based on an Ordovician flysch ichno- HEINBERG, C. 1973. The internal struc- fauna from the Aroostook-Matapedia ture of the trace fossils Gyroohorte Carbonate Belt of northern New Bruns- and Curvolithus. Lethaia, 6, pp. 227- wick. Canadian Journal of Earth 238. Sciences, 17, pp. 1259-1270. HITCHCOCK, E. 1858. Ichnology of New PICKERILL, R.K. and FORBES, W.H. 1979. England. A report on the sandstone Ichnology of the Trenton Group in the of the Connecticut Valley, especially Quebec City area. Canadian Journal of its footprints. W. White (Boston), Earth Sciences, 16, pp. 2022-2039. 220p. RAST, N. and STRINGER, P. 1980. A geo- KEITH, B.D. and FRIEDMAN, G.M. 1977. traverse across a deformed Ordovician A slope-fan-basin-plain model, Taconic ophiolite and its Silurian cover, sequence, New York and Vermont. Jour- northern New Brunswick, Canada. Tec- nal of Sedimentary Petrology, 47, pp. tonophysios, 69, pp. 221-245. 1220-1241. RAST, N., and PICKERILL, R.K. In pre- KSIAZKIEWICZ, M. 1977. Trace fossils in paration. The Carys Mills Formation - the flysch of the Polish Carpathians. an example of fossil contourites. Palaeontologia Polonica 36, 208p. MARITIME SEDIMENTS AND ATLANTIC GEOLOGY 57

ROY, D.C. and MENCHER, E. 1976. Ordovi- SIMPSON, S. 1957. On the trace fossil cian and Silurian stratigraphy of Chondrites.• Quarterly Journal of the northeastern Aroostook County, Maine. Geological Society of London, 112, pp. In Contributions to the stratigraphy 475-499. of New England. Edited by L.R. Page. STANLEY, D.J. and BERTRAND, J.P. 1979. Geological Society of America, Memoir Submarine slope, fan and trench sedi- 148, pp. 25-52. mentation - New concepts and problem SCOTT, R.M. and BIRDSALL, B.C. 1978. solving. Penrose Conference Report, Physical and Biogenic Characteristics Geology, 7, pp. 49-52. of Sediments from Hueneme Submarine STANLEY, D.J. and KELLING, G., Editors. Canyon, California Coast. In Sedimen- 1978. Sedimentation in Submarine Can- tation in Submarine Canyons, Fans, yons, Fans, and Trenches. Dowden, and Trenches. Edited by D.J. Stanley Hutchinson and Ross Incorporated, 395p. and G. Kelling. Dowden, Hutchinson and Ross Incorporated, pp. 51-64. STANLEY, D.J., PALMER, H.D. and DILL, SEILACHER, A. 1959. Zur okologischen R.F. 1978. Coarse Sediment Transport Charakjteristik von Flysch und Molasse. by Mass Flow and Turbidity Current Ecologae Geologicae Helvetiae, 51, Processes and Downslope Transforma- pp. 1062-1078. tions in Annot Sandstone Canyon - Fan Valley Systems. In Sedimentation in 1967. Bathymetry of trace Submarine Canyons, Fans, and Trenches. fossils. Marine Geology, 5, pp. 413- Edited by D.J. Stanley and G. Kelling. 428. Dowden, Hutchinson and Ross Incorpor- 1977. Pattern analysis of ated, pp. 85-115. Paleodiotyon and related trace fos- fils. In Trace fossils 2. Edited by STRINGER, P. and PICKERILL, R.K. 1980. T.P. Crimes and J.C. Harper. Geologi- Structure and sedimentology of Siluro- cal Journal Special Issue Number 9, Devonian between Edmundston and Grand Seel House Press, Liverpool, pp. 289- Falls, New Brunswick. In A guidebook 334. to the geology of northeastern Maine and neighboring New Brunswick. Edited 1978. Use of trace fossil by D.C. Roy and R.S. Naylor. 72nd assemblages for recognizing deposi- Annual Meeting of the New England tional environments. In Trace Fossil Intercollegiate Geological Conference, Concepts. Edited by P.B. Basan. So- Boston College Press, pp. 262-277. ciety of Economic Paleontologists and Mineralogists, Short Course No. 5, TAYLOR, B.J. 1967. Trace fossils from pp. 185-201. the Fossil Bluff Series of Alexander SEILACHER, A. and MEISCHNER, D. 1965. Island. Bulletin of the British Ant- Fazies - Analyse im Palaozoikum des arctic Survey, 13, pp. 1-30. Oslo-Gebietes. Geologische Rundschau, 54, pp. 596-619. TRUMBULL, J.V.A. and McCAMIS, M.J. 1967. Geological exploration in an East SHEPARD, F.P. and DILL, R.F. 1966. Sub- Coast submarine canyon from a research marine canyons and other sea valleys. submersible. Science, 158, pp. 370- Chicago, Rand McNally and Company 372. 381p. VALENTINE, P.C., UZMANN, J.R. and COOPER, SHEPARD, F.P., MARSHALL, N.F., McLOUGH- R.A. 1980. Geology and biology of LIN, P.A. and SULLIVAN, G.G. 1979. Cur- Oceanographer submarine canyon. Marine rents in Submarine Canyons and Other Geology, 38, pp. 283-312. Seavalleys. American Association of Petroleum Geologists, Studies in Geo- WALKER, R.G. 1975. Generalized facies logy No. 8, 173p. models for resedimented conglomerates 58 R.K. PICKERILL of turbidite association. Bulletin of the Geological Society of America, 86, pp. 737-748.

Reviewers: T.L. Harland W.H. Forbes J.B. Hamilton