https://doi.org/10.24199/j.mmv.1978.39.02 7 July 1978

GASTROPODS FROM THE EARLY BELL POINT LIMESTONE, CAPE LIPTRAP PENINSULA, By C. B. Tassell

Albany Residency Museum, Albany, Western Australia

Abstract

One new genus and five new species of gastropods are described from the late Early Devonian Bell Point Limestone, on Cape Liptrap Peninsula, 150 km south-east of . Six other gastropod taxa are recorded. The new genus Bassotrochus is assigned to the family Omphalotrochidae. Together with Orecopia murrayi sp. nov., also from the Bell Point Lime- stone, Bassotrochus angulatus sp. nov. represents the earliest known occurrence of this family to date. The other species are Tropidodiscus waratahensis sp. nov., Straparollus (Euomphalus) sp., ? Mourlonia sp., Gyronema bellense sp. nov., Murchisonia (Murchisonia) bassensis sp. nov., M. (Murchisonia) sp. A, M. (Murchisonia) sp. B and M. (Hormotomina) sp. Also described are Micromphalus clarkei (de Koninck) from near Yass, N.S.W. and an indeterminate form from the Waratah Limestone, Cape Liptrap Peninsula. This shallow water gastropod fauna occurs as both coquinite and non-coquinite assem- blages associated with a diverse invertebrate community which includes corals, stromatopor- oids, bivalves and brachiopods.

Introduction pods have only been mentioned in passing un- The Bell Point Limestone occurs as a small til now. Lindner (1953, p. 82) noted 'a trocho- faulted block on the eastern side of Cape Lip- form gastropod is the only in the lowest trap Peninsula which is approximately 150 km 75 feet'. Above this spiriferid brachiopods oc- south-east of Melbourne. Exposed on this cur together with the gastropod. Higher in the peninsula are sections of the Waratah Bay section 'several small species of gastropods, in- axis, one of a number of such structural axes cluding turreted and turbinate forms' occur. occurring in Victoria. This axis has been the Similarly, Teichert (1954) listed gastropods site of considerable tectonic activity and as a amongst the abundant fauna of the Bell Point consequence some major faults occur on the Limestone at Bell Point. eastern side of the peninsula. Besides the Bell Talent (as cited by Singleton, 1968) listed Point Limestone, certain other units are also Bellerophon and Coelocaulus amongst the only exposed in a few small areas. These in- gastropods occurring in the Waratah Lime- clude the Early Devonian Waratah Limestone stone. The gastropods listed for the Bell Point and the Early Digger Island Lime- Limestone include Tropidodiscus, Amphelissa stone, isisensis and 'a new Trochid'. The limestones at Cape Liptrap have been Bounded by faults and in close proximity known for some time, Ulrich (1875) being to the large Waratah fault, the Bell Point Lime- the first to mention them in print. However, it stone has been subjected to some stress. Partly was not until recently that the stratigraphy of as a result of this many of the gastropods are the area has become adequately known. The distorted, in addition to the crushing and most recent account of the geology being that fragmenting of the shells associated with the of Singleton (1968). initial compaction of the sediment. McCoy (1877) described the first fossil As many of the specimens are either Palaeopora interstincta ( Wahl ) from the crushed, fragmented or distorted the measure- Waratah Bay area. In 1898 Etheridge noted a ments given can only be considered as a gene- dorsal valve of a spirifer, some crinoid frag- ral indication of the specimens' original shape. ments and a new coral Tryplasma. Since then All measurements are in millimetres and the some elements of the limestone fauna including following symbols relating to the measurements corals, ostracods and brachiopods have been have been used: c, number of spiral cords; described. Hap, height of aperture; Ht, total height of Although abundant at Bell Point, gastro- shell; L, length measured at the selenizone in

19 IQ C, B. TASSELL the bellerophontids, Wap, width of aperture; Point constitutes the earliest occurrence of Wh, total number of whorls in shell; Wt, total the family to date. Their presence and that of width of shell. Micromphalus clarki in the Late sedi- All specimens used in this study are lodged ments of the Yass Basin, indicate an affinity in the palaeontological collection of the Na- not previously suspected of the Australian gas- tional Museum of Victoria. tropod fauna with younger Devonian gastro- pod faunas of the Northern Hemisphere (Tas- Age of the Faunas sell, 1976). When Talent (1965) discussed the Bell Point Limestone he commented upon the simi- Palaeoecology larity of the brachiopod fauna to that in the The Bell Point Limestone is a well bedded Buchan Caves Limestone. Such a similarity is dark muddy limestone within which minor also found amongst some of the other faunal amounts of lighter grey limestone and black elements of the two limestones (Vandenberg shale occur. Lindner (1953) considered that it et at., 1976). Philip and Pedder (1967) recog- was at least 140 feet thick. Although there has nized their coral-conodont Fauna D in both been some disagreement about the depth of de- the Buchan Caves Limestone and the Taemas position of the Early Devonian sediments else- Limestone. This coral-conodont fauna is now where in the Melbourne Trough it is generally considered to be Early Emsian in age (Strusz, agreed that the carbonate sediments occurring 1972). on the Waratah Bay axis were deposited in In the older Waratah Limestone, Talent shallow water (Singleton, 1968; Vandenberg (1965) recognized a fauna containing many etal. 1976). elements which showed considerable similarity Part of the prolific and diverse fauna of the to that in found the Coopers Creek Formation. Bell Boint Limestone has been described in the The coral-conodont Fauna B of Philip and past (Hill, 1954; Krommelbein, 1954; Talent, Pedder which has been found in both the 1956; Pedder, 1965). The fauna includes Waratah Limestone and the Coopers Creek stromatoporoids, tabulate and rugose corals, Formation is now considered to be Late Sie- brachiopods, bivalves, rostroconchians, gastro- genianin age (Strusz, 1972). pods and ostracods. The faunas in this unit are As with previous studies of middle Palaeo- preserved in two ways, either as coquinite zoic gastropods in southeastern Australia, this assemblages or non-coquinite assemblages. Al- study makes little contribution toward age de- though less frequent the coquinite assemblages terminations of the limestones. Certainly Mur- are extremely prominent, for example, assem- chisonia (Murchisonia) sp. A from the Bell blages of Orecopia murrayi and Bassotrochus Point Limestone is very similar to Murchisonia angulatus thickly cover surfaces sometimes ex- (Murchisonia) turris de Koninck known to oc- ceeding 25 sq m in area. A characteristic of cur in the Emsian 'Receptaculites' Limestone these coquinite assemblages is their low faunal at Taemas, N.S.W. Similarly the indeterminate diversity. This is true for any such assemblage cyrtoconoid gastropod from the Waratah Lime- whether it is composed of gastropods, bivalves stone would appear to have an affinity with the or any other faunal component. Similar, al- poorly preserved Michelia sp. from the simi- most monospecific, coquinite assemblages have larly aged Toongabbie Limestone. been reported in Eastern North America (Mo-

What is of considerable interest is the pre- Ghee, 1976). sence of the genera Orecopia, Bassotrochus Coquinas composed largely of O. murrayi and Straparollus (Euomphalus) in the gastro- are the most frequently occurring gastropod as- pod fauna. Both Orecopia and Bassotrochus semblages in the limestone. They consist of are members of the Omphalotrochidae, a fam- complete specimens of O. murrayi ranging in ily known principally from the Late Palaeo- diameter from 4 mm upwards, as well as zoic. The presence of these genera at Bell large quantities of angular shell fragments of BELL POINT LIMESTONE GASTEROPODA 21 the same species. Both the fragments and the Tropidodiscus waratahensis sp. nov. complete shells lack evidence of abrasion and (Plate 1, figure 1) transport. S. (Euomphalus) sp. and B. angula- Diagnosis: small form of genus with subdued tus also occur frequently in O. murrayi coquin- dorsal crest and fine closely spaced growth as. Similarly O. murrayi occurs in some of the lines. coquinas composed of B. angulatus or the pre- Description: Small form with angular dorsal sently undescribed bivalves. crest; whorl profile gently rounded between In contrast to the spectacular coquinas of dorsal crest and edge of the umbilicus, then 0. murrayi and B. angulatus the coquinas or rounds more strongly into the umbilicus; um- Tropidodiscus bedding plane concentrations of bilici deep and wide; aperture sub-triangular waratahensis are quite restricted, rarely ex- with a ridge formed by the dorsal crest of pre- ceeding a sq m in area. Unlike O. murrayi ceding whorl on the inner lip; inner lip thin; which occurs in association with bivalves in thick strongly prosocyrt outer lip passes back- some coquinas, those of T. waratahensis contain wards obliquely from the suture to form a numerous brachiopods. Again, evidence of moderately deep v-shaped sinus at the dorsal transport or abrasion is lacking. crest, narrow convex selenizone raised above possess a The non-coquinite assemblages former edges of the slit; fine closely spaced col- much greater faunal diversity. For example M. labral lines. (Murchisonia) bassensis occurs in the light grey limestone with rugose corals, bivalves, bra- Dimensions: chiopods, rostroconchians as well as occasional L Wh— individuals of O. murrayi. M. (Murchisonia) P46963 75 P46964 3 2 sp. B found in a similar limestone is associated P46965 4 3 + rugose corals, ostracods, bivalves, bra- with P46966 7 3+ chiopods, rostroconchians and infrequent ex- P46967 8 — amples of T. waratahensis. of Vic- The composition of this gastropod fauna Location of Types: National Museum E. D. Gill Coll. differs considerably from any other non-platy- toria. Holotype, P46963. of similar age known from south- ceratid fauna Material: Holotype and 20 other specimens. east Australia. Unlike the Lilydale fauna which Besides being substantially smaller is dominated by turbiniform and high spired Discussion: waratahensis has gastropods, notably 'Cyclonema' and some than the type species, T. T. murchisoniaceans, the Bell Point Limestone finer, more closely spaced collabral lines. (Chapman) from Lower Devon- fauna is dominated absolutely by the medium- centrifugalis Loyola in the sized rotelliform O. murrayi. High spired and ian mudstones at Killara and size to T. turbiniform gastropods form only a small com- Melbourne Trough is of similar prominent dorsal ponent of the fauna in numerical terms al- waratahensis. However, its foliaceous though they account for much of the fauna's crest and widely spaced, frequently distinguish it from the Bell Point diversity. collabral lines Limestone species. An undescribed species Systematic Descriptions from the Lilydale Limestone is smaller and has prominent collabral lines than T. warata- Family BELLEROPHONTIDAE McCoy, more 1851 hensis. Talent (1963) described Tropidodiscus sp. Subfamily TROPIDODISCINAE Knight, Kilgower Member, Tabberabbera. 1956 A from the does have fine closely spaced pro- Genus Tropidodiscus Meek and Worthen, This species similar to those of T. 1866 socyrt collabral lines waratahensis. Poor preservation of the slightly Type Species: Bellerophon curvilineatus Con- larger Tabberabbera forms precludes further rad, 1842; Lower Devonian; Schoharie, New comparisons. York. C. B. TASSELL

Family EU0MPHAL1DAE de Koninck, closely spaced growth lines range from fine to 1881 moderately coarse on both the outer and basal Genus Straparollus Montfort, 1810 whorl surfaces; the growth lines continue into Subgenus Straparollus (Euomphalus), the umbilicus. J. Sowerby, 1814 Dimensions: Type Species: Euomphalus pentangulatus J. Ht Wt Hap Wap Wh Sowerby, 1814; Lower ; near P47503 24 59 7 18 5 Dublin, Ireland. P47564 25 53 — — 34- P47505 — — — — 6 Discussion: The variability of specific charac- P47506 15 51 — — 5+ ters in this genus has been commented upon by numerous authors (Knight, 1934; Batten, Location of Types: National Museum of Vic- 1966). The latter author cited the example of toria. Figured specimen P47503. Collected 5. (E) acutits (J. Sowerby) which possesses the T. A. Darragh, 1971. high spired shell of S. (Straparollus) and the Materials: One figured specimen and eight well developed angulate whorl of S. (Euom- other specimens all of which are either crushed phalus). The limited material from the Bell or distorted. Point Limestone provides a further example of Discussion: The small number of specimens this variability. and their poor state of preservation precludes detailed comparisons wtih other members of Straparollus (Euomphalus) sp. the genus and the formal naming of the spe- (Plate figures 1, 15,21) cies. The Bell Point form differs considerably Description: Medium to large low spired gas- from S. (Euomphalus) pentangulatus. The latter tropod with angular whorl profile; sutures dis- is a large discoidal gastropod with a wide um- tinct but variable in form during growth; nu- bilicus and thin lips which contrasts with the merous whorls with profile which varies with low spire, narrow umbilicus and thickened growth and the degree of development of the lips of the Bell Point form. The shape of both upper keel; initially whorls gently rounded to the aperture and lips together with the distinct nearly flat between sutures; with growth, profile peripheral frill of S. (Euomphalus) sp. also flat to gently concave and inward sloping be- serve to distinguish it from the type species. tween the upper suture and the variability de- The Bell Point form can be distinguished veloped upper keel at the junction of the quite readily from the other members of the upper and outer whorl surfaces; the junction genus previously described from Victoria. The of the outer and basal whorl surfaces particu- low spire, narrow umbilicus, aperture shape, larly in the late growth stages forms a pro- thickened lips and relatively few whorls dis- minent narrow thickened peripheral frill; be- tinguish it from the dextrally coiled S. (E.) tween the upper keel and the basal frill the northi (Etheridge) from the Lilydale Lime- whorl profile is gently rounded; base gently stone. S.(S.) serpenteus Talent from the mud- rounded to circum-umbilical swelling where it stones of central Victoria differs from the becomes strongly more arched; narrow distinct Bell Point form in its smaller size, trochiform umbilicus; aperture sub-elliptical; short thick- shape, more numerous whorls, wider umbili- ened columellar lip slightly oblique outwards; cus, apertural shape, growth line characters parietal lip thin; outer lip of moderate thick- and whorl profile. ness extends forwards gently from the upper Talent (cited by Singleton, 1968) included suture to just above the peripheral frill where the gastropod Amphelissa isisensis in the it rounds gently before crossing the base in a faunal list for the Bell Point Limestone. Of all strongly oblique manner; the columellar and the forms known from this limestone, 5. outer lips on the base are strongly concave; (Euomphalus) sp. most closely resembles this where a keel is present a shallow concave species. A. isisensis, the type species of the flexure of the lip may be developed on it; the genus, was described by Etheridge (1921) from BELL POINT LIMESTONE GASTEROPODA 23 the Isis River area, Scone district, N.S.W. This tion in the height of the shell (pi. 1, figs. 16, gastropod occurs in one of two faunas in the 19). These specimens are distinctly trochiform Timor Limestone Member regarded by Voi- in shape, another feature which distinguishes sey and Packham (1969) as . them from 5. (Euomphalus) sp. A re-examina- Unfortunately the quality of Etheridge's il- tion of the type material of A. carinatum is lustrations and the nature of his description required. Whether this results in this genus be- makes comparison difficult. Etheridge (p. 2) ing synonymized with Straparollus (Euompha- noted that 'as the individual specimens vary lus) or establishes a subgenus of Straparollus much in their state of preservation it is difficult characterized by features such as its thickening to select features of a constant character other of the columellar and outer lips remains to be than those of the strongly angular and upstand- seen. Certainly the presence of at least two ing whorls, deeply seated sutures and nearly Devonian low spired euomphalids forms with flat bases'. Subsequently Knight et ah (1960) substantially thickened lips in eastern Australia synonymized Amphelissa with the subgenus S. is of interest. (Euomphalus), Genus Micromphalus Knight, 1945 Although poorly preserved, in each case the similar sized S. (E.) isisensis and S. (Euom- Type Species: Micromphalus turris Knight, phalus) sp. do possess certain similarities. Both 1 945 ; Lower Carboniferous; Elizabethtown, are low spired with 5 to 6 whorls. Both possess Kentucky, United States of America. relatively flat bases with a narrow umbilicus. Range: Late Silurian to Lower Carboniferous. There are also some differences between the The presence of a species of this genus near two forms. While S. (E) isisensts appears al- Yass extends the lower limit of its range from ways to possess a distinct angular keel and Middle Devonian to Late Silurian. deep distinctive sutures this is not always the Distribution: North America and Australia. case with 5. (Euomphalus) sp. Similarly the This is the second record of the genus in Aus- generally distinct peripheral frill of 5. (Euom- tralia; Roberts et ah ( 1967) noted Micrompha- phalus) sp. does appear to be more variably lus sp. amongst a fauna from the developed on S. (E.) isisensis. Certainly it can Westwood Member in the Bonaparte Gulf Ba- be clearly seen in one of Etheridge's illustra- sin of northern Western Australia. tions (plate 1, fig. 1) accompanying his original description. Other details, notably those of Micromphalus clarkei (de Koninck), 1876 the apertural region are lacking for S. (E.) (Plate 1, figures 20, 23) isisensis. Austerum carinatum the type species 1 876 Euomphalus (Omphalotrochus) clarkei of the genus Austerum was described by Hei- de Koninck, p. 41, pi. 1, figs. 7, 7a-7b. decker (1959), from Givetian limestones near Diagnosis: Large low spired form of genus Charters Towers, north Qld. This large, low strongly embracing whorls and narrow spired species possesses a number of charac- with shoulder. teristics similar to those of the Bell Point form. Both are large, low spired gastropods Description: Large, low spired trochiform gas- with sub-elliptical apertures, thickened lips and tropod with each whorl strongly embracing that concave basal and collumellar lips on the basal above; distinct, moderately narrow shoulder; surface. There is also a flexure on the keel. The flat to strongly rounded; gently rounded to flat shallow umbilicus, persistence of the keel whorl profile from edge of shoulder to angular through most growth stages, consistent deep basal whorl periphery; initially sutures im- sutures and lack of a peripheral frill all dis- pressed, with growth become canaliculate; tinguish the north Qld. form from S. (Euom- base rounded; small umbilicus present; aper- phalus) sp. If specimens P47512— 15 from ture circular or nearly so; reflexed columellar near Arthur's Peak in the Fanning River Dis- lip; thin parietal inductura, extends forward trict, north Qld. are indicative of the variations of aperture; moderately thick irregularly pro- in this species then there is considerable varia- socline outer lip; from upper suture the outer 24 C. B. TASSELL lip passes backwards to below the shoulder Af. clarkei differs from the type species in where a distinct but variable shallow concave possessing a lower spire, narrower shoulder, flexure or sinus is developed; the outer lip considerably stronger embracing whorls, more then continues more gently to the whorl peri- variable sutures and being considerably larger. phery; the base is gently rounded; shell of Both possess the distinctive prosocline outer moderate thickness; growth lines strongly fo- lip with a shallow sinus and narrow umbilicus. liaceous. De Koninck, when describing M. clarkei, was aware of its similarity not only with the Dimensions: genus Euomphalus but also with the then re- Ht Wt Hap Wap Wh cently established genus Omphalotrochus. As a P47516 26 58 — — 4+ consequence he placed the species from near P47517 39 59 — — 5 P47519 32 49 13 14 4+ Yass in the genus Euomphalus and the sub- P47520 36 62 — — 5 genus Omphalatrochus,

Location of Types: 1. Euomphalus (Omphalo- Family OMPHALOTROCHIDAE Knight, trochus) clarkei, the specimen figured by de 1945 Koninck was apparently destroyed when the Genus Orecopia Knight, 1945 Garden Palace in Sydney was burnt on Sep- tember 22nd, 1882. Type Species: Platyschisma ? mccoyi Walcott, 1884; Upper Devonian; Nevada, United States 2. Micromphalus clarkei, National Museum of America. of Victoria. Discussion: The presence at Bell Point of this Hypotypes P47517 and P47519, A. J. Shears- genus extends its known distribution. Pre- by Coll. viously it was confined to Europe and North Type Locality: 1. Euomphalus (Omphalotro- America. The Bell Point occurrence also ex- chus) clarkei, Yass District, NSW. tends the lower limit of the generic range from Upper Devonian to Lower Devonian. 2. Micromphalus clarkei, Limestone or Der- ringullen Creek, near Yass, NSW. Orecopia murrayi sp. nov. Stratigraphic Range: Although Shearsby's lo- (Plate 1, figures 6, 8, 12, 13) cality data was vague the nature of preserva- tion of the material from Limestone Creek Diagnosis: Rotelliform member of genus fre- quently lacking umbilicus, with an ovoidal aper- would suggest that it comes from the Bow- ture and variably developed sinus in the outer spring Limestone, a unit containing silicified up. gastropods and brachiopods (Dr K. S. W. Campbell pers. comm.) Brown (1941) has re- Description: Medium rotelliform gastropod corded the occurrence of this gastropod in the with a broad shallow rounded sinus in the Bowspring Limestone, near Yass. This unit was outer lip; whorls each embracing that above; considered by Link (1970) to be Middle Lud- whorl profile flat to gently arched between su- lovian in age. tures; sutures sharp, incised, shallow and ir- regular; basal periphery strongly rounded; base Material: 2 hypotypes and 4 other specimens. flat to gently rounded; small variably de- Discussion: When Knight (1945) erected the veloped umbilicus sometimes present aperture genus Micromphalus, he noted that M. turris ovoidal; columellar lip thickened, and strongly possessed features similar to both Orecopia oblique outwards thins towards junction with and Straparollus. That a form should exhibit outer lip; parietal inductura of moderate thick- features suggestive of a position intermediate ness, occasionally developed forward of aper- to the families and Omphalotro- ture; moderately thick outer lip with u-shaped chidae is consistent with Yochelson's (1956) sinus of variable depth; from upper suture the contention that the omphalotrochids were de- outer lip passes backwards before rounding in rived from the euomphalids. sinus and passing forwards to the periphery —, —

BELL POINT LIMESTONE GASTEROPODA 25 where it turns roundly before continuing back- ing occurs on the base of Scalaetrochus lind- ward, obliquely across the base; below stromi Etheridge from the Lilydale Limestone rounded sinus broad forward projection vari- (Tassell, 1976). Typically the fragmented thin ably developed at or just above the periphery; outer shell layer on the base has been lost. secondary deposits variably developed in peri- Bassotrochus gen. nov. pheral angle; growth lines fine to foliaceous on both outer whorl surface and base; when um- Type Species: Bassotrochus angulatus sp. nov.; bilicus is open growth lines continue into it; Lower Devonian, Bell Point Limestone, Bell occasional growth rugae occur; no other sculp- Point, Victoria. ture developed. Description: Trochiform gastropod with dis- Dimensions: tinct peripheral frill; whorl profile gently con- Ht Wt Hap Wap Wh vexly arched to nearly flat; base gently rounded P46987 15 29 — — 6+ to flat; broad shallow sinus developed in up- P46988 — 35 5 11 per half of outer lip; broad anterior projection P46989 — — 15 developed beneath sinus and above periphery; P46992 . 23 4 8 shell thickened by secondary deposits. P46993 — — 6 8 P46994 8 15 — — 8 Stratigraphic Range: Lower Devonian. P46996 11 17-5 3 — 6+ P46999 13 27 — . Distribution: Bell Point, Victoria. Discussion: This genus was established with Location of Types: National Museum of Vic- some hesitation because of the poor preserva- toria. Holotype, P46987, Paratypes, P46988, tion of the material of the type species B. P46989 and P46990. Collected C. B. Tassell, 1975. angulatus. But the distinctive sinus, albeit shal- low, on the upper part of the outer lip and the Material: Holotype, 3 paratypes and more than protruding lower section of the outer lip clearly 100 other specimens, most of which are indicate its familial relationships. The shallow crushed or fragmented. sinus, peripheral frill, whorl profile and lack Discussion: O. mccoyi (Walcott) is quite vari- of an umbilicus all serve to distinguish this able in shape, Knight (1945, pi. 80, figs, la-g) genus from any of the other trochiform genera figured forms ranging from rotelliform to bee- of this family. Of the genera currently assigned hive like. In contrast O. murrayi is typically to the family Omphalotrochidae, Babylonites rotelliform. Comparison between the Bell from the of North America most Point species and the more rotelliform ex- closely resembles this genus. These two tro- amples of O. mccoyi reveals few differences. 0. chiform gastropods have a relatively shallow murrayi is generally lower spired with a more sinus and weakly developed anterior projection ovoidal aperture resulting from a longer more in the outer lip when compared to Omphalo- outwardly oblique columellar lip. The fre- trochus and Orecopia. Both Bassotrochus and quent absence of an umbilicus, lack of an an- Babylonites possess a thickened periphery. In gulation on the upper whorl surface, and the either genus a shallow depression can be de- apparently more variable depth of the sinus veloped in the thickened periphery which tends

in the outer lip also distinguish O. murrayi to accentuate the peripheral frill. from the type species. However, Bassotrochus angulatus lacking an 0. murrayi has the peripheral angle thick- umbilicus but possessing a convex whorl pro- ened by secondary deposits. As a consequence file differs considerably from the species of the thinnest and weakest section of the base is Babylonites which possess a distinctly concave at the inner edge of the peripheral thickening. to nearly flat whorl profile and an umbilicus. When crushed as is frequently the case at The broad anterior projection beneath the Bell Point, the base is broken and fragmented sinus on the outer lip of Bassotrochus reaches most severely at the inner edge of the peri- its most anterior development above the peri- pheral thickening. A similar pattern of fractur- phery, not at the periphery as in Babylonites. 26 C. B. TASSELL

Although variably developed the peripheral the edge of the peripheral frill and the base; frill of Bassotrochus is generally sufficiently below sinus a broad anterior projection vari- distinct to distinguish it from the blunter peri- ably developed above the periphery; anterior phery of Babylonites. The thickened columel- projection may continue further forward than lar lip and its more strongly prosocline nature the contact of the outer lip with the upper su- also distinguish B. angulatus from the Ameri- ture; thick secondary deposits developed later can species. in periphery; growth lines typically closely The existence of two genera of the family spaced and foliaceous on both the outer whorl Omphalotrochidae in the Bell Point Lime- surface and base; no other sculpture de- stone is of considerable interest. The genus veloped. Orecopia from the Upper Devonian of North Dimensions: America and Europe has been for known Ht Wt Hap Wap Wh some time (Pedder, 1966). Its occurrence at P47479 7 — — — — Bell Point enlarges its range to include the P47480 17 38 — — 4+ Lower Devonian. The presence of Orecopia P47482 12 31 4 8 5+ P47483 16 47 — — and Bassotrochus at Bell Point not only ex- 4+ P47485 24 56 — — 5+ tends the range of the family but increases the P47486 20 45 — — 6+ diversity of the family in the Devonian. How- P47489 19 32 — — 5+ ever, the continuing absence of forms during Location of Types: National Museum of Vic- much of the Carboniferous means that Yochel- toria. Holotype P47480. Paratypes P47481, son's (1956, p. 201) comment that 'it is im- P47482, P47502, P47498. Collected C. B. possible to construct any meaningful family Tassell 1975. phylogeny at this time' is still valid. Material: Holotype, 4 paratypes, 1 hypotype The generic name Bassotrochus is derived and more than 90 other specimens all of which from the trochiform shape of the type species are crusted, distorted or fragmented. and the close proximity of the Bell Point Limestone to . Discussion: Both B. angulatus and O. murrayi occur together in abundance in poorly sorted Bassotrochus angulatus sp. nov. coquinas within the Bell Point Limestone. In (Plate 1, figures 7, 14, 17, 18, 22) each instance many of the shells have been Description: Medium to large trochiform broken and fragmented. However, the two species can be readily distinguished dif- gastropod with thickened peripheral frill; su- by the ferences tures distinct, variable from adpressed to being in their overall shape, nature of their overhung by periphery of preceding whorl; sutures and whorl peripheries, the degree of development of the parietal lips whorl profile gently convex to nearly flat from and the posi- upper suture to near periphery; shallow de- tion of the anterior projection beneath the pression frequently developed in thickened sinus on the outer lip. In addition an umbili- cus is frequently periphery emphasizes basal peripheral frill; developed in O. murrayi. base gently rounded to flat; umbilicus appar- Family EOTOMARIIDAE Wenz, 1938 ently lacking; aperture ovoidal; thickened pro- Subfamily EOTOMARIINAE Wenz, 1938 socline columellar lip with very broad shallow sinus; thins towards junction with outer lip; Genus Mourlonia de Koninck, 1883

parietal lip thin or wanting; outer lip of Type Species: Helix carinatus J. Sowerby, moderate thickness with a very shallow broad 1812; Lower Carboniferous; Mountain Lime- sinus in the upper part; from the upper suture stone, near Settle, Yorkshire, Great Britain. the upper lip passes backwards a very short distance before rounding in the shallow broad ? Mourlonia sp. sinus and continuing forwards to just above (Plate 1, figure 9) the peripheral frill where it turns gently be- Description: Small to medium gastropod with fore continuing backwards obliquely across prominent raised selenizone bordered by two BELL POINT LIMESTONE GASTEROPODA 27 strong spiral cords at whorl periphery; seleni- Range: Ordovician to Middle Devonian. zone located at about mid-whorl; basal and Distribution: North America, Europe, Africa apertural regions unknown; from upper suture and Australia. The occurrence of a species of to selenizone collabral lines prosocyrt; beneath this genus at Bell Point extends the generic selenizone prosocyrt initially; regular collabral range to include Australia. lines strongly developed above and below selenizone; no spiral sculpture developed. Gyronema bellense sp. nov.

Dimensions: (Plate 1, figures 10, 11) Ht wt wh Diagnosis: Typical form of genus with numer- P46975 — 14 4 ous elements of spiral sculpture of only one Location of Types: National Museum of Vic- order and thin inner and outer lips. toria. Figured specimen P46975. Collected C B. Tassell 1975. Description: Medium, turbiniform gastropod with numerous elements of spiral sculpture; Material: Figured specimen. whorls rounded between impressed sutures; Discussion: The incomplete preservation of periphery probably at mid-whorl; base the specimen precludes its confident assignment rounded; small variably developed umbilicus to the genus. The specimen from Bell Point sometimes present; aperture circular; no aper- differs considerably from M. carinata (J. Sow- tural emargination present; columellar lip erby). Above the selenizone of the larger type slightly thickened; thin peripheral inductura species the fine closely spaced collabral lines developed; outer lip moderately thin; straight are weakly prosocyrt to prosocline in contrast and oblique backwards from the upper suture; to the strong prosocyrt lines of the Bell Point fine to slightly foliaceous, prosocline collabral form. The selenizone of the type species with lines present; sculpture composed of regularly its weaker bordering spiral cords is located spaced spiral cords. lower on the whorl than that of the Bell Point form. Dimensions: Ht Hap The larger M. striata (J. Sowerby), type spe- Wt Wap Wh C P46941 — 15 — 4 — 7+ cies of Ptychomphalina synonymized with the P46945 16 15 3+ 10+ genus Mourlonia by Knight et al. (1960) has P46954 — 57 28 25 — 10+ strongly developed collabral lines above and Location of Types: National Museum of Vic- below a selenizone located high on the whorl toria. Holotype P46945. Paratype, P46941. in later growth stages. The selenizone is bor- Collected C. B. Tassell 1975. dered by prominent spiral cords. The colla- bral lines, position of the selenizone and the Material: Holotype, paratype and 1 3 other cords bordering the selenizone are similar to specimens which are all crushed or broken. those developed on the Bell Point form. M. Discussion: The holotype is a crushed incom- talboti (Dickens) described by Batten (1972) plete specimen. Some apertural details are pre- from the Permian of Malaya is similar in size served as are numerous spiral sculptural ele- to the Bell Point form. The Malayan species ments and evidence of its turbiniform shape. also has strong collabral lines and a selenizone The paratype shows clearly the straight colla- bordered by threads located higher on the bral lines. whorl surface. The species from the Bell Point Limestone is Family HOLOPEIDA Wenz, 1938 in many ways similar to G. pulchellum. Both possess thin lips, fine growth lines, a similar Subfamily GYRONEMATINAE Knight, 1956 number of strongly developed cords and pro- Genus Gyronema Ulrich, 1897 minent concave interspaces between the cords, Type Species Trochonema (Gyronema) pul- although in a number of specimens from Bell chellum Ulrich and Scofield, 1897; Middle Or- Point the development of the prominent cords dovician; Chatfield, Minnesota, U.S.A. has been enhanced by subsequent weathering. ci 28 C. B. TASSELL

However, G. bellense can be quite clearly dis- Dimensions: tinguished from the type species by its very Ht Wt Hap Wap Wh much larger size and differing development of P46969a 4 1 7 the cords. P46969b — — 0-5 05 — P46971 4 1*5 — — 1 In terms of size G. bellense is comparable — — with 'Cyclonema' australis Etheridge from the P46970 a 3 1 —8 — 0-6 1 Lilydale Limestone. G. bellense can be dis- P46970b 15 tinguished from this species by its thinner lips, Location of Types: National Museum of Vic- lack of growth rugae, single order of cords and toria. Holotype P46969a. Paratype P46969b. relatively fewer cords. Collected C. B. Tassell 1975. Family MURCHISONIIDAE Koken, 1896 Material: Holotype, paratype and at least 30 Genus Murchisonia D'Archiac and other specimens. DeVerneuil, 1841 Discussion: The principal differences between Subgenus Murchisonia (Murchisonia) M. (M.) bilineata (Dechen), the type species, D'Archiac and DeVerneuil, 1841 and this species are the latter's small size, well rounded whorl profile and selenizone located Type Species: Muricites turbinatus Schlotheim, above mid-whorl. The species from the Bell 1820; Middle Devonian; Stringocephalus lime- Point Limestone also possesses more strongly stone, near Gladbach in Bergischen, Germany. developed collabral lines and weaker spiral cords bordering the selenizone than the type Murchisonia (Murchisonia) bassensis sp. nov. species. (Plate 1, figure 4) A number of other similar sized members of the subgenus are known from Victoria. In most Diagnosis: Small form of subgenus with well cases they are inadequately known because of rounded whorl profile selenizone in upper half poor preservation or lack of specimens. As a of whorl; prominent, well-developed collabral result any comparisons that lines. can be made are

limited. M . (Murchisonia) bassensis can be dis- Description: Small, high-spired numerous tinguished from a number of undescribed mur- whorled gastropod with a selenizone bordered chisoniacians from the Lilydale Limestone by by two fine cords above the rounded mid-whorl its well-rounded whorl profile, strong collabral periphery; whorl rounded; impressed sutures lines and possession of a selenizone located moderately deep; base rounded; lacking um- above mid-whorl. All the specimens from bilicus aperture sub-circular; gently arcuate Lilydale possess prominent cords bordering the columellar lip of moderate thickness; no sug- distinctly concave selenizone in contrast to the gestion of canal-like constriction at junction of subdued cords of M . (M.) bassensis. columellar and outer lips; parietal inductura Chapman (1912) mentioned the presence thin; outer lip with angular sinus that forms a of a small member of the genus in the Buchan slit which generates the selenizone; depth of Limestone. From thin sections it was seen to angular sinus increases with growth; from the have an angular whorl profile and an umbili- upper suture to the selenizone the nearly cus. Other details, notably the presence of a straight outer lip passes posteriorly with only a selenizone, were obtained from a poorly pre- slight obliquity; below the selenizone it passes served specimen P 12873. Typically the genus forwards to the edge of the base before con- Murchisonia lacks an umbilicus. Whether the tinuing backwards across the base; flat seleni- specimens in the thin section were the same zone located above mid-whorl periphery; with as the P12873 is open to question, in any case, collabral lines becoming finer but remain poor preservation precludes comparison with strongly developed; no sculpture. M. (Murchisonia) bassensis. BELL POINT LIMESTONE GASTEROPODA 29

Murchisonia (Murchisonia) sp. A. Murchisonia (Murchisonia) sp. B (Plate 1, figure 5) (Plate 1, figure 3) Description: Medium, high spired gastropod Description: Small, many whorled, high spired with a selenizone on a slightly raised narrow gastropod with a selenizone bordered by two keel at the angular periphery; periphery just prominent coarse cords at the sub-angular above mid-whorl; whorl face flat to slightly mid-whorl periphery; whorl profile sub-angu- concave above and below the selenizone; su- lar; whorl surfaces flat above and below seleni- tures moderately deep; base rounded; umbilical zone; impressed sutures; base rounded; lacking region unknown; columellar lip unknown; mod- umbilicus; gently arcuate columellar lip of erately thick outer lip with deep angular sinus moderate thickness; parietal inductura thin or that forms a slit at the periphery which gene- absent; flat selenizone located at or just below rates a selenizone from the upper suture to the mid-whorl; no sculpture or collabral lines selenizone the prosocyrt outer lip passes pos- present. teriorly with a strong obliquity; below the sele- Dimensions: nizone it passes forwards to the base less Ht Wt Hap Wap Wh strongly; collabral lines fine; no sculptural ele- P46976 a 4 2 5 ments present. P46976 b 7 4 6 P46977 11 5 7 Dimensions: P46978 3-6 5 P46980 4 2-5 6 Ht Wt Wh P46596 17 7 7+ Location of Types: National Museum of Vic- P46957 18 8+ toria. Figured specimen P46976. Collected C. B. Tassell 1975. Location of Types: National Museum of Vic- toria. Figured specimen P46956. Collected Material: Figured specimen and at least 30 CB.Tasselll975. other specimens. Discussion: M. (Murchisonia) bilineata (De- Material: Figured specimen and 6 other speci- chen), the type species, is considerably larger mens which are all crushed or broken. than M. (Murchisonia) sp. B, from the Bell Discussion: poor preservation The of the speci- Point Limestone. Both species possess a dis- mens limits comparison. the The form from tinctive selenizone bordered by two prominent Bell differs Point Limestone from the type spiral cords at an angular mid-whorl peri- species principally in having a selenizone raised phery. These features distinguish them from M. a keel peri- upon on a more angular whorl (Murchisonia) bassensis which occurs at Bell phery. In this respect it is very similar to M. Point. (Murchisonia) gracilicrista Linsley from the The poor preservation of the Bell Point Middle Devonian Anderdon Limestone, Michi- form precludes more detailed comparison be- gan. However, M. (Murchisonia) gracilicrista tween it and the type species as also with has a mid-whorl peripheral selenizone. some undescribed forms from the Lilydale similar The only other form of age and Limestone, similar in size, shape, whorl shape known from Australia is M. (Murchi- profile and selenizone development. sonia) turris described by de Koninck (1876) from the Yass District. Study of material from Subgenus Murchisonia (Hormotomina) the Taemas limestones reveals some differences Grabau and Shimer, 1909. between M. (Murchisonia) turris and the spe- Type Species Murchisonia maia Hall, 1861; cies from Bell Point. M. (Murchisonia) turris Middle Devonian; Columbus limestone, near has a more rounded whorl profile with a con- Dublin, Ohio, U.S.A. cave selenizone located on keel at the peri- Murchisonia (Hormotomina) sp. phery. From the upper suture the outer lip does not pass backwards as strongly as in M. Description: Medium high spired gastropod (Murchisonia) sp. A. with a median spiral thread on mid-whorl sele-

ct 30 C. B. TASSELL nizone; whorl profile rounded; impressed su- to the form from the Waratah Limestone. tures; base unknown; apertural details poorly Talent (as cited by Singleton, 1968) included known outer lip thick with a shallow concave Coelocaulus in a faunal list for the Waratah slit that generates a slightly elevated selenizone Limestone. This genus had been synonymized bordered on each side by prominent cords; with Michelia by Knight et al. (1960). Thus it sculpture absent. is possible that the unidentified form may be a member of the genus Michelia. Dimensions; Ht Wh Acknowledgements P46968 48 8 Location of Types: National Museum of Vic- I wish to thank Mr T. A. Darragh of the toria. Mentioned specimen P46968. Collected National Museum of Victoria, Melbourne for C.B. Tassell 1975. his discussion and criticism of this work; Dr O. P. Singleton and Dr P. J. Coleman for Material: Mentioned specimen. their helpful comments, criticisms and dis- Discussion: The poor preservation of the speci- cussions; Margaret Tassell for the photographs men from Bell Point Limestone and the type and discussion throughout this study. species prevents effective comparison of these similar sized forms. The only similar described References form from Victoria is Gyrodoma etheridgei Batten, R. L., 1966. The Lower Carboniferous gas- (Cresswell) from the Lilydale Limestone. This tropod fauna from the Hotwells Limestone of large high-spired gastropod also has a me- Compton Martin, Somerset, pt. 1. Palaeont. Soc. dium spiral thread developed on a mid-whorl 509: 1-52. selenizone in some instances. However, this , 1972. Permian gastropods and chitons from species is characterized by the presence of nu- Perak, Malaysia. Bull Amer. Mus. Nat. Hist. 147(1): 5-44. merous fine spiral sculptural elements of two Brown, T. A., 1941. The Stratigraphy and structure or more orders. of the Silurian and Devonian rocks of Yass-Bown- ing district, New South Wales. /. Proc. R. Soc. High-spired gastropod gen. et sp. indet. N.S.W., 74: 312-341. (Plate 1, figure 2) Chapman, F., 1912. Reports on —Middle Description: Small to medium cyrtoconoid gas- Devonian of the Buchan district. Rec. geol. tropod; numerous whorls with gently convex Surv. Vict. 3(2): 218-222. Etheridce, R., 1898. Record of Fossils. Rep. Prog. whorl profile between shallow impressed su- geol. Surv. Vict. 9: 125-126. tures; no other details preserved. , 1921. Palaeontologia Novae Cambriae Dimensions: Meridional is—Occasional descriptions of New South Wales fossils—No. 8. Rec. geol. Surv. Ht Wt Wh N.S.W. 10(1): 1-11. P46974 7 4 6 Heidecker, E., 1959. Middle Devonian molluscs from Location of Types: National Museum of Vic- the Burdekin Formation of North Queensland. toria. Figured specimen, P46974. Pap. Dep. Geol. Univ. Qd. 5(2): 3-8. Type Locality: Waratah Limestone about Hill, D., 1954. Devonian corals from Waratah Bay, Victoria. Proc. R. Soc. Vict., 66: 105-118. 100 m west of Bird Rocks, near Walkerville Knight, J. B., 1934. The South. gastropods of the St. Louis, Missouri outlier: vii. The Euom- Stratigraphic Range: The Waratah Limestone phalidae and Platyceratidae. /. Paleont. 8(2): is considered by Strusz (1972) to be Pragian. 139-166. Knight, J. B., 1945. Some new genera of Paleozoic Material: Figured specimen and one other . Ibid, 19(6): 573-587. specimen. Knight, J. B., R. L. Batten and E. L. Yochelson, 1960. Descriptions of Paleozoic Discussion: Michelia sp. described by Talent Gastropoda In Moore, R. C. (Ed.), Treatise on Invertebrate and Philip (1956) from the similar-aged Toon- Paleontology: Part I. (1), Univ. Kan- gabbie Limestone, Marble Creek is similar sas Press. — ,

BELL POINT LIMESTONE GASTEROPODA 31

Koninck, L. G. de, 1876. Recherches sur les Fossiles Tassell, C. B„ 1976. A Revision of the Gastropod Paleozoiques de da Nouvelle—Galles du Sud fauna of the Lilydale Limestone (Early Devon- (Australie). Mem. Soc. Roy. Sci. Liege. 2, 6. ian) of Victoria. Mem. natn. Mus. Vict. 37: (Translated, 1898, as: Descriptions of the Pal- 1-22. aeozoic fossils of New South Wales (Australia). Teichert, C, 1954. Note on Devonian Limestones Mem. geol. Surv. N.S.W., Palaeont. 6.). between the Bluff and Bird Rock, Waratah Bay, Krommelbein, K., 1954. Devonische Ostracoden Victoria. Proc. R. Soc. Vict. 66: 103-104.

aus der Gegend von Buchan und von der Kuste Ulrich, G. H. F., 1875. Observations on the Waratah der Waratah Bay, Victoria, Australien. Sencken- Bay Limestone. Rep. Prog. geol. Surv. Vict. 2; bergiana 35: 119-229. 125-126. Lindner, A. W., 1953. The Geology of the coastline Vandenberg, A. G. M., M. J. Garratt and D. Spen- of Waratah Bay between Walkerville and Cape cer-Jones, 1976 Silurian-Middle Devonian Liptrap. Proc. R. Soc. Vict. 64: 77-92. In Douglas, J. G. and Ferguson, J. A. (Eds.), Link, A. G., 1970. Age and correlations of the Siluro- Geology of Victoria. Spec. Publ. geol. Soc. Aust. Devonian strata in the Yass Basin, New South 5.

Wales. /. geol. Soc, Aust. 16(2) : 711-722. Voisey, A. H. and G. H. Packham, 1969. Sediments McCoy, F., 1877. Record of Fossils. Rep. Prog. geol. of the Tamworth Group. In Packham, G. H. Surv. Vict. 4: 156. (Ed.), The Geology of New South Wales. A geol. Soc. Aust. 1-654. McGhee, G. R., 1976. Late Devonian benthic marine 16(1): communities of the central Appalachian Alleg- Yochelson, E. L., 1956. Permian Gastropoda of the heny Front. Lethaia., 9: 111-136. south-western United States: I. Euomphalacea, Trochonematacea, etc. Bull, Amer. Mus. Nat. Pedder, A. E. H., 1965. A revision of the Australian Hist. 110: 173-260. Devonian corals previously referred to Micto-

phyllum. Proc. R. Soc. Vict., 78(2) : 201-220.

, 1966. The Upper Devonian gastropod Orecopia in western Canada. Palaeontology Explanation of Plate 9(1): 142-147. PLATE 1 Philip, G. M. and A. E. H. Pedder, 1967. A corre- lation of some Devonian limestones of New Figure 1 Tropidodiscus waratahensis, P46963, ho- South Wales and Victoria. Geol. Mag. 104: 232- lotype, x3. 239. Figure 2—High-spired gastropod gen. et sp. indet., Roberts, J., P. J. Jones and E. C. Druce, 1967. P46974, x3. Palaeontology and correlations of the Upper Figure 3 Murchisonia (Murchisonia) sp. B., Devonian of the Bonaparte Gulf Basin, Western P46976, x5. Australia and Northern Territory. In Oswald, Figure 4 Murchisonia (Murchisonia) bassensis, D. H., Ed. International Symposium on the De- P46969, holotype, x4. The aperture vis- vonian System, Calgary, 1967. 2 vols. Alberta ible is of another specimen of this species.

Society of Petroleum Geologists, Calgary. 5 Murch ison ia (Murch ison ia) sp . Figure A . Singleton, O. P., 1968. Geology of South . P46956, x2. In McAndrew, J., and Marsden, M. A. H. (Eds.), Figure 6—Orecopia murrayi, P46990, paratype, xH. Regional guide to Victorian geology, School of Basal view. Geology, University of Melbourne, Publication Figure 7 Bassotrochus angulatus, P47502, para- No. 1. type, x2. Strusz, D. L., 1972. Correlation of the Lower De- Figure 8 Orecopia murrayi, P46987, holotype, xl. vonian rocks of Australasia. /. geol. Soc. Aust. Figure 9—? Mourlonia sp., P46975, xli. 18(4): 427-455. Figure 10 Gyronema bellense, P46941, paratype, x2. Talent, J. A., 1956. Devonian brachiopods and pele- Basal view. cypods of the Buchan Caves Limestone, Vic- Figure 11 Gyronema bellense, P46945, holotype, xl. toria. Proc. R. Soc. Vict,, 68: 1-56. Figure 12 Orecopia murrayi, P46988, paratype, xl.

-, 1963. The Devonian of the Mitchell and Basal view. Wentworth Rivers. Mem. geol. Surv. Vict. Figure 13 Orecopia murrayi, P46987, holotype, xl. 24: 1-118.78 pi. Figure 14 Bassotrochus angulatus, P47498, para- 1965. The Stratigraphic and diastrophic type, xl. evolution of central and eastern Victoria in Figure 15 Straparollus (Euomphalus) sp., P47503, middle Palaeozoic times. Proc. R. Soc. Vict. xl. Basal view. 79: 179-195. Figure 16 Austerum carinatum Heidecker, P47513, Talent, J. A. and G. M. Philip, 1956. Siluro-De- xl. Fanning River district, Queensland. vonian Mollusca from Marble Creek, Thomson Figure 17 Bassotrochus angulatus, P47482, paratype, River, Victoria. Ibid. 68: 57-71. xli. Basal view. ,

32 C. B. TASSELL

Figure 1 $—Bassotrochus angulatus, P4748 paratype, 1 , Figure 21—Straparollus (Euotnphalus) sp. P475 1 1 x l- xr,. Basal view. Figure 19—A usterum carinatum Heidecker, P47514, Figure 22—Bassotrochus angulatus, P47480, holo- xl. Fanning River district, Queensland. type, xl. Figure 20— Micromphalus clarkei (de Koninck), Figure 23—Micromphalus clarkei (de Koninck), P47517, xf. Derringullen Creek near P47519, x$. Basal view. Derringullen Yass, N.S.W. Creek, near Yass, N.S.W. MEM. NAT. MUS. VICT. 39 PLATE