51/- to X Ft x? to VN CO S > 'X^TX' 5 - N^v > T ION 1/7 NOliOillSNI ^NVINOSHIHMS^S 3 I U V aail^LIBRARI ES^SMITHSONIAN ^INSTITUTION NOUOll z t- Z * Z W co g* * m CO _ ^ w *; co _ ijgn LIBRARIES SMITHSONIAN INSTITUTION NOliOillSNI NVINOSHllSNS S3 I M Va a 11 L I B R A I 3 a 1 1 Z co z > CO Z w z - Z V^S. .X —l >V^ffP5?kA 37- -v\ —4 0m&LAto». 2! 5? 8 TION NOliOillSNI NVINOSHillMS SBIHVHaH LIBRARIES SMITHSONIAN INSTITUTION NOIlOl . « o> HSII LIBRARIES SMITHSONIAN INSTITUTION NOIiOlUSNS NVIN0SH1IWS S3 !H VH 8 I1_L1 B RAI r* z o rgy W m 22 m w m co _ co _ CO X _ co JTION NOliOillSNI NVINOSHIIINS SBiaVHail LIBRARIES SMITHSONIAN INSTITUTION NOIlOl CO Z CO Z » . co Z C" S yA\\SOV/^x S , ^ &5v\ S < X _ ^ : *% i i ^ I > "•W4r 5 > '/w** 2 ^ 2 > z co z co * z co z aan libraries Smithsonian institution noiioiiisni nvinoshhws S3 i ava a ii_li b ra co Z CO ~ W 1X1 s , *% /3m&\ - i A. — o CO X o r i W V*77"' | %/?** 1 i CO •*■*' Z CO Z CO V 2 CO noshjliins S3iavaan libraries Smithsonian institution NoiiniiisNi_NvmosHiiiA!s S3 to — to — co z \ w ^ w - j|||S^ 1 ~ v ^ 5 7 5 O —I z _j z —i z — ' ITHSONIAN INSTITUTION NOlIfUllSNI NVIMOSHIIWS S3IUVH9n LIBRARIES SMITHSONIAN INS r~ Z t~ z r- z r- A^VtSO\^*s. 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CD 'V 3) > m x^ojTjwpz m ^ ^ x^ims^z rn nq/v. qc>-' ^ m CO ~ to X _ to _ to iNOSHiiws S3iavaan libraries Smithsonian institution NoiiruiiSNi nvinoshiiws S3 Z . to ^ ... CO z CO s to » Z co Z CO ITHSONIAN _ INSTITUTION NOimillSNI NVINOSH1IWS SBIBVyail LIBRARIES SMITHSONIAN INS to — co x to / a;/ A, < to z 3 / VOLUME 5 • PART 3 Palaeontology OCTOBER 1962 PUBLISHED BY THE PALAEONTOLOGICAL ASSOCIATION LONDON Price £3 THE PALAEONTOLOGICAL ASSOCIATION The Association was founded in 1957 to further the study of palaeontology. It holds meetings and demonstrations, and publishes the quarterly journal Palaeontology . Membership is open to individuals, institutions, libraries, &c., on payment of the appropriate annual subscription : Institutional membership. ... £5. 5.?. ($15.50) Ordinary membership . . . . £3. 3s. ($ 9.50) Student membership .... £2. 2s. ($ 6.50) There is no admission fee. Student members will be regarded as persons receiving full-time instruction at educational institutions recognized by the Council. Subscrip- tions are due each January, and should be sent to the Treasurer, Professor P. C. Sylvester-Bradley, Department of Geology, The University, Leicester, England. Palaeontology is devoted to the publication of papers (preferably illustrated) on all aspects of palaeontology and stratigraphical palaeontology. Four parts are published each year and are sent free to all members of the Association. Members who join for 1962 will receive Volume 5, Parts 1 to 4. Volumes 1 (4 parts), 2 (2 parts), 3 and 4 (4 parts each) are still in print, and may be purchased separately at a cost of £2 ($6) post free for each part; orders should be sent to the approved agents, Messrs. B. H. Blackwell, Broad Street, Oxford, England. Manuscripts on all aspects of palaeontology and stratigraphical palaeontology are invited. They should conform in style to those already published in this journal, and should be sent to Mr. N. F. Hughes, Sedgwick Museum, Cambridge, England. A sheet of detailed instructions for authors will be supplied on request. ADDENDUM Plate 36 (Vol. 5, Part 2) : scale lines on figs. 1-3 represent 500f/,, and those on figs. 4-7, 100/x. THE PALAEONTOLOGY OF THE NAMURIAN ROCKS OF SLIEVE ANIERIN, CO. LEITRIM, EIRE by the late Patricia j. yates Abstract. On Slieve Anierin the Lower and Upper Eumorphoceras Stages of the Namurian contain an un- broken sequence of faunas; these are described in detail for the first time in Ireland. The simple geological struc- ture enables marine bands to be collected in their undoubted order of superposition, in contrast to some equivocal sections elsewhere in Britain. Shale is the dominant rock type throughout the succession, but a thick grit, with coal seams, occurs in the lower part of E2. The faunas of the marine bands consist dominantly of goniatites and lamellibranchs, the most common gonia- tite genera being Eumorphoceras, Cravenoceras, and Cravenoceratoides, with Anthracoceras and Dimorphoceras abundant at certain levels. The goniatite species have relatively short time ranges and are unsurpassed for the recognition of zones and subzones. The lamellibranch species usually have longer time ranges, but are also shown to be valuable stratigraphically, supplementing the goniatites. The following new species and subspecies are described: Eumorphoceras rostra turn; E. bisulcatum erinense, ferrimontanum, and leitrimense; Posidonia cor- rugata elongata and gigantea; Caneyella membranacea horizontalis ; Obliquipecten cost at us; Posidoniella variabilis erecta; and Chaenocardiola bisati. Detailed stratigraphical correlations are made with beds of the same age in Ireland, the Pennine region in England, north-west Europe (notably Germany and Belgium), and North America. Some important revisions in correlation are suggested, and the remarkable extent of Namurian goniatite-lamellibranch faunas is demon- strated. Editorial note. Miss Yates died on 7 August 1960 at the early age of twenty-eight, only five days before the examination of a thesis she had prepared for the Ph.D degree of the University of London. Since this work is a major contribution to Carboniferous stratigraphical palaeontology, it has been edited for publication (with the consent of her brother. Dr. E. M. Yates, Department of Geography, King’s College, London) by Dr. W. H. C. Ramsbottom (Geological Survey Office, Ring Road Halton, Leeds 15) and Dr. Gwyn Thomas (Department of Geology, Imperial College, London, S.W.7). The title of the thesis has been retained for this paper, and the editors have not introduced material not known to the author or published since her death. Thanks are due to Mrs. Judith Creighton for undertaking the difficult task of sorting the author’s manuscripts and cataloguing her extensive col- lections. Repository. Copies of the author’s thesis (containing some palaeontological descriptions not included in this paper) are in the Watts Library of Geology, and the author’s collection is housed in the Murchi- son Museum, Department of Geology, Imperial College, London. Registration numbers without a prefix in the paper refer to specimens in this collection. Specimens in the Geological Survey Museum which are referred to in the text have the prefix GSM, and those from the British Museum (Natural History) the prefix BM. Localities. Fossiliferous localities on Slieve Anierin, including those in Pi and P2, are shown on text- figs. 2, 3, and 4, and listed in the Appendix. Each Irish Ordnance Survey 6-inch sheet has been divided into sixteen quadrants ; the figure in brackets following the sheet number is the number of the quad- rant in which the locality referred to may be found, and is followed by the locality number, e.g. Leitrim 20(8)1, abbreviated to L20(8)l. It has been found necessary to renumber the specimens and localities mentioned in Y ates (1 96 1) ; a check list of the new numbers is given in the Appendix (section 2). Abbreviations. The only departure from the normal custom of abbreviation of generic names to the initial letter is the use of Ct. for Cravenoceratoides, in order to avoid confusion with C. for Cravenoceras. Authorship of species and subspecies. The authorship of the chief species and subspecies mentioned in this paper is as follows: Anthracoceras glabrum (Bisat), A. paucilobum (Phillips), A. tenuispirale [Palaeontology, Vol. 5, Part 3, 1962, pp. 355-443, pis. 51-62.] C 674 A a 356 PALAEONTOLOGY, VOLUME 5 Demanet ; Cravenoceras africanum Delepine, C. cowlingense Bisat, C. gairense Currie, C. holmesi Bisat, C. leion Bisat, C. malhamense (Bisat), C. subplicatum Bisat ; Cravenoceratoides bisat i Hudson, Ct. edalense (Bisat), Ct. lirifer Hudson, Ct. nitidus (Phillips), Ct. nititoides (Bisat), Ct. stellarum (Bisat); Dimor- phoceras looney i (Phillips); Eumorphoceras angustum Moore, E. bisulcatum Girty, E. bisulcatum gras- singtonense Dunham and Stubblefield, E. bisulcatum varicata Schmidt, E. girtyi Elias, E. hudsoni Gill, E. medusa Yates, E. medusa sinuosum Yates, E. plummeri Miller and Youngquist, E. pseudobilingue (Bisat) emend. Moore, E. pseudobilingue A Bisat, E. pseudobilingue C Bisat, E. pseudocoronula Bisat, E. rota Yates, E. sp. form A Moore, E. stubblefieldi Moore; Girtyoceras limatum (Miller and Faber), G. meslerianum (Girty); Goniatites elegans Bisat, G.falcatus Roemer, G. granosus Portlock; Kazakho- ceras scaliger (Schmidt); Lyrogoniatites newsomi georgiensis Miller and Furnish; Neodimorphoceras hawkinsi (Moore); Nuculoceras nuculum Bisat; Sudeticeras alaskae Gordon, S. crenistriatum (Bisat), S. newtonense Moore. Actinopteria fluctuosa (Etheridge), A. persulcata (M‘Coy); Caneyella membranacea (M'Coy), C. wapanuckensis (Girty); Chaenocardiola footii (Baily), C. haliotoidea (Roemer); Dunbarella elegans (Jackson); Euchondria levicula Newell; Obliquipecten laevis Hind; Posidonia becheri Bronn, P. cor- rugata (Etheridge), P. lamellosa (de Koninck), P. trapezoedra Ruprecht; Posidoniella sulcata (Hind), P. variabilis Hind; Pseudamusium praetenuis (von Koenen). Leiorhynchus carboniferus polypleurus Girty, Lingula parallela Phillips, Orbiculoidea nitida (Phillips), Productus hibernicus Muir-Wood; Thrincoceras hibernicum (Foord), Stroboceras subsulcatus (Phillips), Cycloceras purvesi Demanet; Mour Ionia striata (de Koninck); Archaeocidaris urii (Fleming); Weber ides cf. W. shunnerensis (King); Coleolus namurcensis Demanet. The goniatite zones established by Bisat had not been extensively applied in Ireland until Hodson (1954o) made the first attempts to interpret previous records and discover new fossiliferous localities in Co. Clare; this led to a fuller understanding of Upper Carboniferous palaeontology and palaeogeography in Ireland and gave this field of study a great stimulus. The Eumorphoceras Stage has not previously been the subject of detailed study in Ireland. Smyth (1950) described part of E2 in North Co. Dublin but as this was only a portion of a larger work the description was not detailed; furthermore the complex structural pattern made the interpretation of the succession difficult. Nevill (1957) described the Summerhill Basin, Co. Meath, but again no detailed study of the faunas was possible. At Professor Hodson’s suggestion a reconnaissance was made of Benbrack Moun- tain, which lies south of Cuilcagh (2,188 ft.) (see Padget 1953), on the borders of Co. Fermanagh and Co. Cavan, but although Eumorphoceras bisulcatum Girty (GSM 95317) was collected from the summit the exposures were thought to be too poor for further work. Slieve Anierin (1,927 ft.), which lies south-west of Benbrack in Co. Leitrim, proved to be more suitable, since a virtually continuous succession from basal Px up to E2b is for the most part well exposed in stream sections, the Ei and E2 beds being particularly fossiliferous; moreover the area is fortunately not complicated structurally (text-fig. 1). In the north of England there are many records of exposures of beds from the Ex and E2 Zones but no really continuous section is available except from borehole records. Hudson and Cotton (1943, pp. 142—73) described the Ex and E2 succession from a bore- hole in Alport Dale in Derbyshire. Although a borehole section is obviously of con- siderable value in establishing the order of superposition of many previously isolated records, there are equally obvious advantages in being able to collect over a continuous succession of beds, concentrating on particularly fossiliferous levels and obtaining a P. J. YATES: NAMURIAN OF SLIEVE ANIERIN 357 text-fig. 1 . Map of Slieve Anierin showing the outcrops of the main marine bands in the Lower and Upper Eumorphoceras Stages. far wider picture of the fauna at such levels than can possibly be obtained from one borehole core. The value of the exposed succession on Slieve Anierin thus lies in the unbroken sequence of faunas which it provides. The fauna is described and figured, and correlations made with other areas. Slieve Anierin lies in an area of Upper Carboniferous rocks which extends from the 358 PALAEONTOLOGY, VOLUME 5 southern tip of Lough Allen northwards for about 30 miles to the northern extremity of Lough Erne. At its greatest width this outcrop stretches for about 20 miles westwards from Swanlinbar in the east. The outcrop narrows northwards and is interrupted by a deep embayment of Carboniferous Limestone in the Belcoo area, to the north of which it widens again but rapidly narrows towards Lough Erne. Slieve Anierin lies at the southern end of this mass on the eastern side of Lough Allen. Slieve Anierin is a flat-topped mountain with a prominent grit escarpment, which from a distance is easily mistaken for the summit of the mountain; in fact 200 feet of shales form a small residual outlier overlying the grit. The solid geology is virtually limited to stream sections by a thick obscuring mantle of peat bog and glacial drift below the grit escarpment (text-fig. 1), while high-level peat bog forms a thick mantle over most of the upland plateau above. The rocks are normally horizontal or only very gently dipping (up to about 5°), except in landslipped areas. Previous work. Slieve Anierin was first mapped for the Geological Survey of Ireland by R. J. Cruise, and the results were published in 1876 on 1-inch Sheet 67. An explanatory memoir appeared in 1878. written by Cruise with palaeontological notes by W. H. Baily. The map shows Lower Coal Measures at the summit of the mountain overlying Millstone Grit, in which there are coal-seams; the slopes of the mountain below the Millstone Grit are mapped as Yoredale Beds (shales with ironstones). Much of this memoir is devoted to the Arigna Mountains on the west of Lough Allen, including Kilronan to the south and Altagowlan further north, which are still being mined for coal. The coal from Kilronan was first used around 1788 to smelt the clay-ironstone bands which are very prolific in the lower shales. Despite glowing reports of the great economic possibilities of the coals on the Arigna Mountains by Griffith (1818) and by later authors, the history of the Connaught coalfield has hardly fulfilled early expectations. Du Noyer (1863) published a map of the mountains to the west of Lough Allen, gave the coal analyses earlier published by Kane (1845) and stated that the coalfield had ‘little prospect of ever being properly developed’. In the 1 878 memoir it is stated that there are two coal-seams within the grit on Slieve Anierin corre- sponding with the lowermost (or Crow Coal) and the Middle Coal on the Arigna Mountains. Above the grit the Lower Coal Measures are said to be brown and black splintery shales attaining a consid- erable thickness and apparently without the top coal seam seen on Altagowlan. However, the Dail Commission of Inquiry into the Reserves and Industries of Ireland (1921, p. 132) reported that there was no information on the top coal but that it was said to exist on Altagowlan and on Slieve-an-Iarain but not on Kilronan. Altagowlan, being 300 feet higher than Kilronan, contains the upper strata in- cluding the third seam. On Slieve Anierin there is certainly no coal seam above the grit escarpment and it seems unlikely that it exists on Altagowlan either. Boate (1652) said that ‘The mountains on the east side of Lough Allen are so full of this metal, that thereof it hath got in Irish the name Slew Neren, that is, mountains of iron’. Hull (1878, p. 38) refers to Slieve-an-Ierin (or the Iron Mountain), and describes shales with rich beds of ironstone, regarded as the Yoredale Shales of the north of England, overlain by the Millstone Grit. He also refers (pp. 39, 40) to Gannister Beds or Lower Coal Measures, 600 feet in thickness, with two or three seams of coal and several beds containing marine genera such as Phillipsia, Orthoceras, Goniatites, Productus, Pallustra, Orthis, &c. These beds are said to occur on the tops of the hills bordering Lough Allen. They are now proved to be of E2 age on Slieve Anierin. In a later work Hull (1881, pp. 330-3) published a section, based on one given by Du Noyer (1863, p. 84, fig. 4), dealing with the area west of the Lough and showing three coal-seams on Kilronan and two on Altagowlan. Du Noyer’s original section in fact carries the two seams on Altagowlan over to the other side of the Lough to Slieveanierin Mount. The recognition of this third seam on Kilronan by Du Noyer and by Hull thus appears to be at variance with the memoir, which places a third seam on Alta- gowlan but not on Slieve Anierin or Kilronan. The Memoir, in turn, differs from the Dail Commission which, although admitting that no information was available on this seam, placed it on Altagowlan and on Slieve Anierin. Cole and Halissy (1924, pp. 31, 32) do not differentiate between Kilronan and Altagowlan but refer P. J. YATES: NAMURIAN OF SLIEVE ANIERIN 359 only to Arigna. They mention only a lower and upper coal, the inference being that they only believed in the existence of two coal-seams, but this is never actually stated. They suggest (p. 32) that the upper coal is in true Coal Measures ‘which here remain only as a capping to the highest hills’. Later Charles- worth (1953, p. 93) referred to a Leitrim Coalfield, specified three coal-seams and reproduced Hull’s figure (originally taken from Du Noyer). He also subscribed to the view that some Lower Coal Meas- ures occurred in this area. The succession on Slieve Anierin does not get higher than the Namurian. The geology of Cuilcagh, to the west of Swanlinbar, was described by Padget (1953, pp. 17-27) but the details of the faunas given by him are disappointing, since they might be expected to correlate with the succession on Slieve Anierin. The great grit escarpment on Slieve Anierin corresponds to that on Cuilcagh, and yet the E2 horizons which can be demonstrated to exist below the grit on Slieve Anierin do not seem to have been found on Cuilcagh. It is possible, however, that scree in the Sruh Croppa (the stream which Padget (p. 19) refers to as yielding the most complete succession) may have obscured the horizons below the grit which are better exposed on Slieve Anierin. Cuilcagh appears to have been a much more visited mountain than Slieve Anierin; Phillips (1836, introduction, p. 15) describes a visit made to Cuilcagh from Florence Court, the home of the Earl of Enniskillen, where he was staying with Sedgwick, Murchison, Griffith, Sir Phillip Egerton, and Agassiz. Caldwell (1959, pp. 163-89, pi. 6), in his account of the Lower Carboniferous rocks of the Carrick- on-Shannon Syncline, describes the lithology and fauna of the Roscunnish Shales in the Aghagrania River; they are of Px and P2 age and immediately underlie the author’s basal Ei beds. The highest faunal band on Slieve Anierin is of E2 age and thus the summit is in Nam- urian deposits and not in true Lower Coal Measures. The Gastrioceras subcrenatum Marine Band, which is the horizon used in western Europe to define the base of the Lower Coal Measures, has been detected in the Leinster Coalfield (Nevill 1956), where true Lower Coal Measures are in fact present, but on Slieve Anierin there is no in- dication of it or of stages H and R. The Millstone Grit with Coal Seams of the Memoir (1878) is clearly the grit which forms the escarpment on the mountain. Since it can now be demonstrated that Eumor- plioceras bisulcatum occurs beneath this grit and Cravenoceratoides eda/ense almost directly above it, the grit must therefore lie within E2. The Ct. edalense beds are con- sidered to be at the level of Ct. bisati, which also occurs but is much less common. Hudson (1945) has placed the Ct. bisati subzone at the base of the Ct. nitidus zone. It is thus possible to assign the grit to E2a or E2b, but for convenience the edalense beds themselves are considered to be the base of E2b and the grit assigned to E2a. Both the grit and the beds above it are therefore placed in the Arnsbergian stage of the Namurian (Hudson and Cotton 1943, p. 152). The two coal-seams within the grit marked on the 1-inch geological map may, with some difficulty, be traced along the grit escarpment on the western side of the mountain. On the southern flanks, however, they are completely obscured by drift deposits, but are misleadingly continued as broken lines on the map. An attempt was made in 1957 to mine the lower coal-seam about 400 yards west of the Rocking Stone but the level was abandoned. The coal is poor in quality and the seams are probably impersistent. On the eastern side of the mountain there is another aban- doned level to the west of the track on Leitrim 21(9). An old coal level is marked on the 6-inch map to the east of the track, but has not been found; it may be the one mentioned by Cruise (1878) as being above Aughacashel House and in the upper seam, which was found to be 1 foot thick. The level to the west of the track is certainly in the lower seam (about 3 ft. 6 in. thick). Coal-seams are not unknown from within the Millstone Grit series elsewhere, though they are usually poor in quality; e.g. the Bradley Coal 360 PALAEONTOLOGY, VOLUME 5 occurs within the Skipton Moor Grit, of Ej age, in the Bradford and Skipton area (Stephens et al. 1953, p. 17). The so-called Yordale Beds extend down to the Lough edge on the west and to the top of the Carboniferous Limestone on the south and south-east. The term Yoredale is not particularly well chosen for these beds. The name was first used by Phillips (1836, pp. 36-37), with the type section in Wensleydale. Hudson (1926, pp. 125-35) subsequently amplified the term and described the Yoredale Beds as essentially a shallow- water series in which a rhythmic unit passing from shale through sandstone to limestone is continually repeated; goniatites are rare in these deposits. The shales on Slieve Anierin are in no way comparable with such a succession. At the base of the succession occur text-fig. 2. Map showing the northern area of fossiliferous localities on Slieve Anierin, including the Stony River. limestones, calcareous mudstones, and sandstones which are known to be of Pj and P2 age but from the base of the Namurian upwards shales were deposited continuously until the grit horizon. The only variation within this series is a greater concentration of clay ironstone bands at certain levels. They are a notable feature on Slieve Anierin; in the Stony River in particular the large nodules which weather out of these bands are seen plentifully in the river bed. Some bands in the shales are extremely fossiliferous and goniatites are very abundant, together with lamellibranchs. The succession has more in common with that described by Parkinson (1936, pp. 318-19) for the Upper Bowland Shales of the Slaidburn district of Yorkshire, where at least 400 feet of shales with gonia- tites and lamellibranchs as the common fossils succeed the P2 beds. The onset of the Pendle Top Grit, however, occurs a short distance above C. malhamense, i.e. at a lower horizon than the grit on Slieve Anierin. The 1-inch geological map shows some faulting of the grit and overlying shales but no supporting field evidence has been found. Impressive landslides have occurred along the western face of the mountain and at the south-western and south-eastern corners; the faults are all thought to be due to a failure to appreciate the magnitude of the land- slipping. A fault shown on the 1-inch map between Slieve Anierin and the mountain to the north is continued as a broken line across the upper reaches of the Stony River but P. J. YATES: NAMURIAN OF SLIEVE ANIERIN 361 the faunal band exposed at L2 1 (5) 1 1 does not appear to be displaced. Two faults have been inferred on the basis of displacement of faunal bands on the southern flanks of the mountain; it is impossible to do more than tentatively suggest the position of these faults (text-fig. 1). Acknowledgements. It is my pleasant duty to acknowledge all the assistance I have received during the course of this work. Mr. W. S. Bisat has been a constant source of advice and encouragement on all matters relating to the goniatites; his unflagging interest has always been an invaluable stimulus. Dr. Gwyn Thomas has read and criticized this manuscript and has given much assistance over all aspects of this work. Mr. Murray Mitchell has provided easy access to material at the Geological Survey Museum, and in particular I am grateful for the ease with which I have been able to borrow specimens to photo- graph. Dr. W. H. C. Ramsbottom has also rendered assistance in discussion on several points. Pro- fessor Hodson must be thanked for my first introduction to the Namurian of western Ireland and for advice on photography. Thanks are also due to the Central Research Fund of the University of London for several grants towards field expenses. (The editors also wish to express their appreciation of the generous grant received from the Central Research Fund to defray the cost of the collotype plates in this paper.) FAUNAL SUCCESSION Throughout the succession lamellibranchs and goniatites are particularly abundant and in numbers of individuals and of species are dominant over all other groups. The number of goniatite genera is small ; Eumorphoceras, Cravenoceras, and Craveno- ceratoides are the most important and their various species are representative of definite levels in the succession. Anthracoceras and Ditnorphoceras are abundant at certain levels, but are considered to be less valuable because of the difficulties of identifying species when no sutural evidence is available; only one species of Anthracoceras is of real value in indicating a precise stratigraphical level. At the horizons in which Anthracoceras or Ditnorphoceras abound, other goniatite genera usually do not occur in any abundance and are sometimes absent. This probably reflects differences in the conditions under which the two groups of genera flourished, a phenomenon which has already been observed in deposits of this age. Hudson and Cotton (1943, p. 151) believed that the Anthracoceras — Ditnorphoceras faunas could exist in sea water less saline than normal. Bisat, Duncan, and Moore (1931, p. 4), comment- ing on the occurrence of Anthracoceras in the Upper Limestone Series of Scotland and in the Coal Measures of England, believed that this genus could withstand conditions which could not be tolerated by other goniatite genera. In beds on Slieve Anierin in which Ditnorphoceras and Anthracoceras abound, these goniatites are usually associated with Posidonia and Posidoniella. These two lamellibranchs also occur abundantly with the other goniatite genera but appear to be the only genera able to survive the condi- tions in which Anthracoceras and Ditnorphoceras flourished. It seems, however, that Anthracoceras had greater powers of resistance to a less favourable environment than even these two lamellibranchs, since over considerable barren thicknesses of shale with only plant fragments and Lingula, a stray Anthracoceras can still occasionally be found, but no lamellibranchs. It is a matter for conjecture why certain levels were so extremely fossiliferous and why conditions then were so suitable for goniatites and lamellibranchs. Hudson and Cotton (1943, p. 150) suggested that salinity was a controlling factor. At periods of maximum freshwater intake, and therefore low salinity, the faunas were unable to survive; at 362 PALAEONTOLOGY, VOLUME 5 periods when the freshwater intake was low and the salinity correspondingly high normal marine populations were able to flourish. An additional factor, however, has to be considered in the Slieve Anierin area, since the unfossiliferous shales frequently contain numerous clay-ironstone bands, often separated by only a few inches of shales. At these horizons the amount of iron in solution may well have made conditions in- tolerable for marine organisms, even those like Dimorphoceras, Anthracoceras, or Lingula which could tolerate low salinity. At most of the fossiliferous levels in the Namurian beds on Slieve Anierin the number of individuals is usually very high whereas the number of species and genera is low. Two of the richest levels in genera and species are both in E2 deposits. The lower yields about twelve species, the assemblage consisting entirely of goniatites and lamellibranchs, apart from some crinoidal debris and a nautiloid. The highest faunal band on the mountain is undoubtedly the richest in numbers of individuals, genera, and species, and in the diversity of the groups represented; apart from the ubiquitous goniatites and lamellibranchs there are brachiopods, trilobites, gastropods, fish remains, bryozoa, echinoid spines and plates, and crinoidal debris. It is also the most narrowly con- centrated band, extending through only about 10-12 inches of rock. Other faunal bands, with far fewer species and consisting entirely of goniatites and lamellibranchs, extend through 10-12 feet of strata. During P2 times in the Slieve Anierin area, the deposition of argillaceous material became increasingly important and there was a diminution in the more calcareous shallower-water deposits which were laid down in Pi and previous periods. By early Namurian times shales were the established lithological type. The shales of fossiliferous horizons are fairly solid and tough, and frequently split into large slabs, but those of the intervening unfossiliferous horizons are noticeably far more fissile and fragmentary, a slight tap with a hammer usually resulting in a cascade of small splinters of shale. P-l-P-z Faunas The shales between the Carboniferous Limestone and the Millstone Grit were origin- ally mapped as Yoredale Shales, but the succession in no way resembles the Yoredale succession in Yorkshire. In addition to the systematic study of the Namurian shales on Slieve Anierin, some collecting was also carried out in the Upper Visean deposits (P2 and P2) which outcrop on the lower slopes of the mountain, chiefly on the southern and south-eastern sides, in order to trace the base of the Namurian (text-figs. 1, 3, 4). Caldwell (1959, pp. 178-80) has given some details of the Px and P2 beds in the Agha- grania River, where the succession is best seen, but the beds are only broadly divisible into the subzones established elsewhere on the basis of goniatites. Hodson and Moore (1959, pp. 384-96) were able to collect beautifully preserved goniatites in P2b on Dough Mountain, farther north in Co. Leitrim, thus accentuating the very poor and scanty material available on Slieve Anierin at least in Px. The succession in the Aghagrania River consists (see also Caldwell 1959) of alterna- tions of shales, calcareous mudstones, mudstones, and muddy limestones. At Aghagrania Bridge a sandstone 20 feet thick is exposed. There is also an intercalation of decalcified limestone north of the bridge at L23(4)19, where the section is at least 30 feet high; there are many sandy seams, and the whole exposure has a curiously slumped appear- ance. Goniatites, broadly referred to the striatus group, has been collected below the .s Ih #0> 'q < #0> c/5 c o as a o t/) o o as text-fig. 3. Map showing the central are; 364 PALAEONTOLOGY, VOLUME 5 sandstone south of Aghagrania Bridge, together with Posidonia becheri, Thrincoceras hibernicum , poor pleurotomariid gastropods, brachiopods, and orthoceratids. North of the bridge, above the sandstone intercalation but below the decalcified beds, P. becheri continues to be very abundant and occurs with rarer DunbareUa elegans, Mourlonia striata, rare spines of Archaeoeidaris urii, and rare Goniatites cf. G. falcatus. Above the decalcified beds there is a slight improvement in the faunas ; softer mud- text-fig. 4. Map showing the southern area of fossiliferous localities on Slieve Anierin, including the Aghagrania River. stones are present at the base of L23(4)19 but shales become the dominant rock type at about 8 feet above the base of this section and, apart from occasional hard calcareous mudstone bands, apparently continue at least to the base of Ex. At about 3 feet above the base of L23(4)19 Leiorhynchus carboniferus polypleurus occurs in abundance, while in a mudstone 3 feet above this again there are abundant examples of Goniatites granosus associated with Sudeticeras cf. S. crenistriatum. The genus Sudeticeras with crenulate radials is typical of P2 deposits while G. granosus is very abundant in the G. granosus subzone (P2a) elsewhere. At about 20 feet above the base of this section Sudeticeras sp. is abundant in shales, accompanied by very rare G. granosus, and with the first appear- ance of Caneyella membranacea s.l., which has not been seen lower in the succession. P. becheri does not occur at these P2 levels, in contrast to its extraordinary abundance lower in the succession. P. corrugata becomes common in P2 at about the same time as Caneyella, although it may also occur lower than Caneyella. DunbareUa continues into these P2 levels. The problematical striated tube-like structure Coleolus namurcensis P. J. YATES: NAMURIAN OF SLIEVE ANIERIN 365 Demanet, which also occurs rarely in beds, is very abundant in the lower beds at L23(4)19. Another feature noted at about the level at which Caneyella appears in the upper part of L23(4)19 is the appearance of a thin, compressed and sharp-ventered goniatite referred to Kazakhoceras sp.; this species continues into Ej and may in part be the same form as that mentioned and figured by Nevill (1957, p. 296, pi. 22, figs. 6, 7). Two other exposures continue the succession. Locality L20(12)l yields C. mem- branaceo s.l. and Sudeticeras cf. S. newtonense. The presence of Caneyella indicates an horizon at least as high as the highest band at L23(4)19. S. newtonense is placed high in the succession of species of this genus (Moore 1950, p. 47). Locality L23(4)16 (which is close to L23(4)9, where basal Ej beds are exposed) yields C. membranacea s.l. and Lyrogoniatites newsomi georgiensis. Bisat (1950, p. 12) refers the latter to a band at the top of the Visean. A clay-like band with a rich and varied fauna occurs at L23(4)17 and also high in the section at L23(4)15. At the latter locality, however, basal Ex material occurs in the scree in front of the section and is believed to come from a horizon not far above the clay band which, although it has a rich fauna including two lamellibranch species which become very abundant in undoubted Ex beds, does not itself include Ex goniatites. The fauna of the clay band includes Weberides sp., Chonetes sp.. Lingula cf. L . parallela, P. corrugata, Pseudanmsium cf. P. praetenuis and Obliquipecten costatus sp. nov. Various exposures are seen along the course of the Aghagrania River to the east of L23(4)18 and most are high in P2 and below the basal Ej band which is present at L23(4)9 and at high levels in L23(4)15. Farther north-east there are exposures of the decalcified beds seen just south of L23(4)19. The decalcified limestones are often extremely white and cherty, and rusty sands also occur. These beds have not been collected exhaustively but have yielded Productus sp. and crinoidal debris. A good exposure of these decalcified beds occurs at L24( 1)1 with an excellent exposure of basal Ej farther upstream at L24(l)l. Unfortunately the intervening exposures are inaccessible, but this is the part of the succession which is exposed, at least in part, at L23(4) 19. Farther north-east in Doherty Stream East (L21(14)14 and 15) there is a succession of alternating shales, mudstones, calcareous mudstones, and limestones similar to the succession south of Aghagrania Bridge. P. becheri and Goniatites of the striatus group (see Hodson and Moore 1959) occur. Beds very rich in P. becheri occur at L2 1(14)12. At L21 ( 1 4) 1 1 and in a deep gorge to the north-west, at least 40 feet of sandstone horizons and some sandy shales occur, containing only poor brachipods and Dunbarella sp.; these beds have been correlated with the sandstone at Aghagrania Bridge. At L21( 14)10 a hard calcareous mudstone occurs at the base, overlain by about 10 feet of pale, decalcified and sandy beds reminiscent of the decalcified beds seen in the Aghagrania River at L23(8)l. In Doherty Stream East L21 (1 4)9 yields only C. membranacea s.l., and is therefore some distance up in the P2 succession. At L21( 14)8 there is a rich faunal band which is the equivalent of that seen at L24(l)l and is undoubtedly basal E2 in age. The section in this stream is therefore broadly comparable with the main Aghagrania River section, although the good goniatite material above the decalcified beds is not exposed in it, the only faunal evidence for P2 being C. membranacea. In Doherty Stream West, rich P. becheri beds occur at L21(14)17 to 20 and are prob- ably partly equivalent to those seen at L2 1 ( 1 4) 1 2 in the eastern stream. The overlying 366 PALAEONTOLOGY, VOLUME 5 40 feet of sandstones and soft sandy shales (with some coaly layers) are at an equivalent horizon to L21(14)ll in the eastern stream. No further exposures occur in Doherty Stream West until L2 1 (14) 1 6, where beds with Cravenoceras leion indicate an Ex horizon. It is suggested that the sandstone horizon seen at Aghagrania Bridge thickens north- eastwards in this direction, while the underlying limestones and calcareous mudstones are more numerous at the expense of the shale and mudstone horizons. It is not pos- sible, however, to estimate whether the whole succession is actually thicker than in the Aghagrania River, since the top of the Cavetown Limestone which lies below the Px beds is not exposed; the Cavetown Limestone is well exposed in the lower reaches of Doherty Stream East. The north-easterly thickening of the Px sandstone would not be inconsistent with the appearance of a sandstone horizon at the base of the ‘Yoredale Shales’ on Cuilcagh (Padget 1953; and Irish Ordnance Survey Maps 67 and 56), where the lowest collected horizon in the Yoredale Shales is Pxb. Pendleian and Arnsbergian faunas The appearance of Eumorphoceras and Cravenoceras at the base of the Namurian is a striking event in the sequence of goniatite faunas and the former genus is used as a name for the basal division of the Namurian; beds are said to be of Lower or Upper Eumor- phoceras Age (Ex or E2 respectively). Several of the stage names originally suggested by Bisat (1928, pp. 125-30) have now been replaced by others. The most important for the present study are Pendleian, proposed by Hudson and Cotton (1943, p. 152) to replace Bisat’s Grassingtonian for beds of Lower Eumorphoceras Age, and Arnsbergian, pro- posed by the same authors for beds of Upper Eumorphoceras Age to replace Bisat’s Lower Sabdenian. These stages are further subdivided into zones and subzones: E., Zones and Subzones Stage Zone Nuculoceras nuculum Arnsbergian Cravenoceratoides nitidus Eumorphoceras bisulcatum s.s This table is based on a portion of one published by Hudson (1945, p. 2). The in- clusion of the Nuculoceras nuculum zone in the Sabdenian (Homoceras Age) is the prac- tice adopted in the Bradford and Skipton Memoir (Stephens et al. 1953, p. 95) but does not concern the present work. The succession of zones within the Pendleian Stage adopted in the same Memoir (op. cit., p. 91) is as follows: E1 Zones Cravenoceras malhamense EjC Eumorphoceras pseudobilingue Exb Cravenoceras leion Exa The appearance of Eumorphoceras and Cravenoceras at the base of the Pendleian on Slieve Anierin is accentuated by the relative poorness of the Pa and Px faunas in the area. Subzones I Nuculoceras nuculum I Cravenoceratoides nititoides (Cravenoceratoides stellarum Cravenoceratoides nitidus Cravenoceratoides bisati (Not divided) P. J. YATES: NAMURIAN OF SLIEVE ANIERIN 367 The genus Girtyoceras, from which Eumorphoceras probably evolved, is here absent from the P2 and Px horizons, but elsewhere appears to have been fairly abundant at the end of P2 times. Moore (1946, pp. 387-445, pi. 22-27) described several new species of Girtyoceras from horizons in Lancashire and Yorkshire ranging from B2 to P2. Bisat (1936, pp. 533-4) suggested that Cravenoceras was probably derived from Beyriclio- ceratoides, which is found elsewhere in the Visean zone B, and lingers on sporadically into Ex but after Pxa is never common. In the Slieve Anierin area there are no deposits of B age, and Pxa beds (although probably present south of Aghagrania Bridge) yield only very poor Goniatites sp. (a) Cravenoceras leion zone ( E 1a). Reference has already been made to the clay band with a rich fauna devoid of goniatites which is believed to be just under the base of Ex at L23(4)15 and 17. At L24(l)l and at L21(14)8 the faunas consist of Eumorphoceras pseudo cor onula , E. rota, C. leion, P. corrugata, Chaenocardiola bisati sp. nov., Pseuda- musium praetenuis, Kazakhoceras sp. Above this rich fauna there are beds several inches thick with only Caneyella membranacea. P. praetenuis was also a prominent member of the clay band seen elsewhere without goniatites and believed to be slightly lower than this material. Caneyella was frequently abundant towards the top of P2 where it was associated with Sudeticeras. At L23(4)9 and at L20(8)l slightly later Ex faunas occur. The most abundant goniatite is C. leion, mostly in the form of very small young individuals. Specimens of Eumor- phoceras are extremely rare and are referred to E. pseudo cor onula; at L20(8)l a possible E. cf. E. sp. form A Moore also occurs. The fauna is dominated by Obliquipecten costatus sp. nov., which is so abundant that the beds are reminiscent of those in Px dominated by P. becheri. In the clay band just under the base of Ex O. costatus sp. nov. was associated with other lamellibranchs, brachiopods, and trilobites; at this higher level in Ex it is extremely abundant and continues through at least 2 feet of beds. Chaenocardiola bisati sp. nov. does not continue from the lower level at L24(l)l. At L23(4)7 there are beds extremely rich in E. pseudobilingue A and C. leion, the latter of normal adult size; no lamellibranchs occur. The sequence of faunas described so far is contained within about 10 feet of sediment, in contrast to some later levels where one fauna appears to continue through this thickness with little or no change. At the base of Ex there is a rapid succession of faunas in a short vertical sequence, with scarcely any unfossiliferous sediments (see Table 1). After E. pseudobilingue A the next species in ascending sequence to occur in great abundance is Posidonia trapezoedra, which extends through 10 feet of shales. This form is believed to be very close to P. corrugata seen lower in the succession but has strong radial corrugations in addition to the concentric folds, and a very characteristic outline as the name implies. In the lower part of its range it is associated with Kaza- khoceras sp. which is believed to be the same form with a carinate venter as that seen high in P2. The succeeding beds consist of a narrow band with E. medusa, which is closely related to E. pseudocoronula seen very near the base of Ex. Stray specimens of Kazakhoceras sp. also occur at this level, with P. trapezoedra and P. corrugata, but the dominant lamel- libranch is Pseudamusium praetenuis, which occurs sparsely with E. pseudocoronula near the base of Ex. Very rare specimens of C. leion are still present. E. medusa sinuosum has i 8 i | U. £ £$£ 531 ? lias 3H1 A8 a3033DDnS ,OOI SQNV8 SNOlSNOai AVID H1IMS33VHS S 00333 1 11 SSO3N0 1 II II ,OS SQNVg 3 NOIS NOd I AV13 HUM S31VHS SflOd33 111 SSOdNfl $5 eg W ki Z o o O M 9 ooi sanvHS snob3d nissojNn i Q 3 S O d X 3 ION l Lx 1 kj ki ki kj ki 3 Ul £ <2 5: ? o il kj kj >* k § I 5 § § I <0 3 I Uj 5 Q. § to 5) ■t J CO to Q,' O O o 0. Q: Q § £ 0. s o Q Anierin, compiled from localities below the grit. P. J. YATES: NAMURI AN OF SLIEVE ANIERIN 369 been collected at L23(4)2 from what is believed to be a later horizon and where it is still associated with P. trapezoedra ; a rare example has also been collected at L20(8)2 where the beds are dominated by E. medusa, as at L21(14)6 and 7. The highest fossili- ferous level in the C. leion zone apparently occurs at L23(4)2. Some of the goniatites referred to as Kazakhoceras sp. may correspond to those re- ferred to by Nevill (1957, p. 296, pi. 22, figs. 6, 7); they have a notched venter, and appear in P2 and Ex. There are also some extremely large compressed specimens, so far only seen at L24( 1)1, which have a sharp venter, an ornament very like a Dimorphoceras with two forward bows in the striae between the umbilicus and the venter, but which possess a definite nautiloid suture. The series of faunas so far described occur in rapid succession within about 30 feet of beds. Within this comparatively small thickness of rock the genus Eumorphoceras shows a rapidly evolving series of species, reflecting a period of great activity following the inception of the genus. In contrast, Cravenoceras appears to have been more conserva- tive, and one species, C. leion, which it has not been possible to subdivide, persisted with the several species of Eumorphoceras throughout the succession. There follows a considerable thickness (up to about 100 feet) of unfossiliferous sedi- ments. Ironstone bands are a feature of these beds, though they are not so frequent as later in the succession, and stand out from the shales which form dreary and steep ex- posures on either side of the Stony River. ( b ) Eumorphoceras pseudobilingue zone (Ef). This portion of the succession can be seen in the Stony River to the north, and in the headwaters of the Aghagrania River to the south, and close correlation exists between these two areas (text-figs. 1-4). The unfossiliferous shales with ironstones are followed by beds with fairly abundant Eumorphoceras cf. E. angustum, but with the conservative Posidonia stock persisting together with the Kazakhoceras sp. from Exa. The first species to appear above the un- fossiliferous horizon at L2 1(5)1 and 2 is P. trapezoedra, which was also the last to be seen in Exa. The two goniatite species have been collected not only in the Stony River at this level but also in the Aghagrania River at L21( 13)9 and 10. No new species of Cravenoceras occur at this level nor indeed any evidence of the genus. E. cf. E. angustum probably has its maximum abundance in the upper parts of the P. trapezoedra beds. In Doherty Stream East, at L21(14)5, it is seen abundantly with P. corrugata, P. trapezoedra, and Kazakhoceras sp. above a considerable thickness of unfossiliferous shales with clay-ironstone bands which succeed the last indications of the C. leion zone with E. medusa at L2 1(14)6. Succeeding the beds with E. cf. E. angustum there are beds with abundant E. pseudo- bilingue s.s. occurring in large flat slabs of dark-grey shale characteristic of this level, e.g. at L2 1(5)4 (c. 20 feet), and L23(4)l. It is associated with less abundant examples of the two species of Posidonia seen lower in the succession; rare specimens of Chaeno- cardiola footii also occur. Fifteen feet of similar beds occur in the Aghagrania River at L21(13)8; at the base occurs a thin band, which is also seen at L2 1(5)4, above the beds with E. pseudobilingue s.s.; it is dominated by P. corrugata, most of which are very small; it also yields rare Chaenocardiola footii and Cycloceras purvesi. At this level occur a few specimens of a Eumorphoceras which is neither E. angustum of the lower horizon nor E. pseudobilingue 370 PALAEONTOLOGY, VOLUME 5 s.s., which at L21(5)4 is collected directly below it. It is referred to as E. pseudobilingue C. The nature of the ribbing in these specimens is very like that of E. pseudobilingue s.s. but the decided groove at the shoulder is unlike the latter. The sparse collecting contrasts with the abundance of E. cf. E. angustum and E. pseudobilingue s.s. below. Between L21(13)9 and 10, and 8, there is an overgrown waterfall where collecting is difficult, and this is the level at which E. pseudobilingue s.s. occurs at L2 1(5)4. Above the harder pseudobilingue material is a barren succession 8-10 feet thick, also seen at L2 1(14)1 and 4 in Doherty Stream East, with many horizons of very thinly leaved shales which still weather out into particularly large rectangular slabs. No clay- ironstone bands occur. They are overlain by the calcareous horizon with C. malhamense (EiC). (c) Cravenoceras malhamense zone (Zqc). Within 40 feet or less of beds it is possible to distinguish a lower group of goniatites which culminates in E. pseudobilingue s.s. followed closely by E. pseudobilingue C and an upper group in which there are no speci- mens of Eumorphoceras but in which the most common goniatite is C. malhamense , with far less common Kazakhoceras scaliger. As yet no undoubted specimens of E. bisulcatum have been seen and the beds are still regarded as Pendleian. Elsewhere in El5 e.g. in the borehole section from Alport Dale in Derbyshire (see Hudson and Cotton 1943, pp. 167-8), the C. leion zone is succeeded by the E. pseudobilingue s.s. zone and then the C. malhamense zone (EjC). This division is also applicable on Slieve Anierin, where the last two zones are concentrated into a relatively thin sequence, though in the absence of faunal evidence it is impossible to determine the exact position of the unfossiliferous beds below Eumorphoceras cf. E. angustum within Exa or Effi. It is noticeable that on Slieve Anierin the beds with Eumorphoceras in Effi do not contain any species of Cravenoceras and the reverse is true in the higher beds with C. malhamense. However, this was not so at the Exa levels where the two genera occur in apparently equal abundance. At the base of L2 1 (5)5 a hard calcareous mudstone, 1 foot thick, yields C. malhamense and is overlain by fairly solid shales which fracture irregularly. At about 1 foot above the hard mudstone the shales become thinly leaved and contain abundant Caneyella mem- branacea through a thickness of about 3 feet of beds ; C. malhamense is more sparse than in the lower calcareous horizon, and Kazakhoceras scaliger also occurs. The doubts over the true affinities of the latter are mentioned on p. 393 but as the ornament seems unmistakable and as it is clearly indicative of certain levels, Schmidt’s specific name has been retained here. This is the lowest horizon at which this species has been collected during the present work. At L21(13)7 in the Aghagrania River it occurs with C. malhamense above E. pseudobilingue C; specimens of Actinopteria persu/cata also occur, but this species has not been collected elsewhere on Slieve Anierin at this level. The fossiliferous beds are succeeded by an unfossiliferous sequence 150 feet thick similar to the lower one separating the E^ and Exb fossiliferous levels, except that here the clay-ironstone bands are far more numerous and are often separated by only a few inches of unfossiliferous strata. Upstream from L2 1(5)5 the sections in the Stony River take on the dreary character (already seen below the E. angustum beds) of high exposures of very friable shales with frequent ironstone bands which diminish in frequency upwards, particularly through the upper 50 feet or so of beds. P. J. YATES: NAMURIAN OF SLIEVE ANIERIN 371 (d) Cravenoceras cowlingense fauna ( Low Em). The next fossiliferous level is exposed in the Stony River, and can be traced along the sides of the valley high above the unfos- siliferous sediments until at L21(5)9 it occurs at stream level and forms a prominent waterfall. Collecting from this horizon is easiest at L2 1(5)9, but it is also accessible at L2 1(5)8 some distance above the river bed. The same horizon is exposed in the Agha- grania River at L21(13)5 and 6; the former locality occurs high on the valley side and the total thickness is not exposed; at the latter the entire horizon is present, overlain by unfossiliferous beds. The beds at these levels are more arenaceous than those lower in the succession but never show the large rectangular slabs which are characteristic of the E. pseudobilingue beds. The sequence is about 20 feet thick and the fauna, which is poor in species and also in individuals compared with lower and higher levels, remains the same throughout. It is dominated by Cravenoceras, and the specimens are all believed to belong to C. cowlingense Bisat. One rare specimen displays a suture-line and it is very like the suture figured for this species by Hudson (1941, p. 281) from material collected by him in Mirkfell. A few rare specimens of E. bisulcatwn s.l. were collected, and therefore this faunal band is the first in E2. The specimens are figured and described, and are compared with E. bisulcatwn grassingtonense Dunham and Stubblefield (1944, pp. 258-60, pi. II, figs. 4 a-c). The only other goniatites at this level are poor specimens of Dimorphocera- tids which, in the absence of sutural evidence, are of little value. A rare specimen of Stroboceras subsulcatus (Phillips) was also collected; this form was also noted at lower levels in Ex. Chaenocardiola footii and the ubiquitous P. corrugata continue from lower levels, but P. trapezoedra, which occurs in great abundance lower down, has not been found at this level. P. lamellosa occurs but is never abundant, and might at first sight be easily mistaken for P. becheri from Px beds, though there are sig- nificant differences. These beds are succeeded by 40-50 feet of very friable unfossiliferous shales, again with frequent clay-ironstone bands which are particularly abundant in the middle 20 feet of the sequence. (e) Eumorphoceras bisulcatum fauna ( High Em). The fauna of the next fossiliferous horizon is still dominantly a cephalopod-lamellibranch fauna, though a great deal of crinoidal debris occurs, for the first time above the more calcareous horizons of the Visean. Sedimentation was slower at this time than in the earlier period when the beds with C. cowlingense were being deposited. The horizon, which is estimated to be only 6-8 feet thick, is rich both in numbers of species and individuals when compared with the lower fauna with C. cowlingense as the dominant goniatite seen at L21(5)8 and 9, and at L21(13)5 and 6. The band is seen at three localities. At L21(5)10 the lower part of the band, of which about 4 ft. 6 in. are exposed, is seen at the top of the section overlying unfossiliferous friable shales. At the other two localities the base of the band is not exposed but the upper part and the over- lying unfossiliferous sediments are seen; at L21(5)ll about 4 feet of the band occurs at stream level; at L21(13)4, where some excavation is necessary, about 2 feet are exposed in the valley side with unfossiliferous shales above. There are slight faunal differences between the basal beds at L21(5)10 and the upper beds at the other two localities. Most of the fauna is common to all three localities; the b b C 674 372 PALAEONTOLOGY, VOLUME 5 most abundant constituent is E. bisulcatum; E. bisulcatum erinense subsp. nov. is only seen in the lower beds associated with rare specimens of E. bisulcatum ferrimontanum subsp. nov., which succeeds it and which is dominant in the higher parts of the sequence at L21(13)4 and at L21(5)ll, where the lower subspecies no longer occurs. Both sub- species are in many respects close to E. bisulcatum s.s. but significant differences exist; they appear to be closer to E. bisulcatum s.s. than to other subspecies, namely E. bisul- catum grassingtonense Dunham and Stubblefield, E. bisulcatum varicata Schmidt, and E. bisulcatum mut. B Schmidt. The subspecies of Eumorphoceras are accompanied at this level by Cravenoceras cf. C. gairense, specimens of which are easily distinguished by means of three raised spiral lines around the umbilicus (a diagnostic feature, which is not seen in any other species of this genus). It has been collected at all three localities but is never as abundant as either subspecies of Eumorphoceras. Kazakhoceras scaliger, which occurs in E, with C. malhamense and Caneyella membranacea, also occurs at the three localities. Its two associates do not survive Ex times but K. scaliger apparently has a wider range. However, these are the only two levels at which this problematical species has been seen. Anthracoceras glabrum occurs at the three localities but is decidedly more abundant in the lower levels at L21(5)10. Very rare specimens of the conservative Stroboceras subsulcatus also occur, contrasting with the more rapidly evolving goniatites. Neither C. membranacea s.s. nor C. membranacea horizontalis subsp. nov. persist beyond Ei beds, but at this level in E2 an elongate subspecies of P. corrugata occurs, which it is thought may have been misidentified as C. membranacea by other authors; it is described as P. corrugata elongata subsp. nov. It is always associated with the ubiqui- tous P. corrugata, the most abundant species in the entire succession, and abundant specimens of the persistent Chaenocardiola footii, which occurs at several levels in E2 and in E2. The latter was not present in the faunas of the C. leion zone at the base of El9 but Chaenocardiola bisati sp. nov. occurs at this level. Chaenocardiola never occurs in such swarms as some of the species of Posidonia, but it reaches its acme at this horizon. Dunbarella aff. D. elegans is present, although this record does not conform with the horizon given by Jackson for the species; it is thought that the forms at this level are identical with those in P2 and P2. The species was not collected at any level in Ex but is present again at this horizon in E2. (/) The arenaceous interlude. The very fossiliferous beds at L21(13)4, L21 (5)1 1 , and L21(5)10 are followed by about 100 feet of shales with clay-ironstone bands increasing in abundance upwards, overlain by a massive quartzitic grit, about 200 feet thick, which forms the prominent escarpment on the western and eastern sides of Slieve Anierin. Two thin coal-seams of poor quality occur within the grit; the lower is the most easily traced, and varies in thickness up to about 3 feet; the upper seam is only up to 1 foot in thickness, and is separated from the lower by about 50 feet of flagstones and sandy shales with plant remains. The lower part of the grit consists of the more massive beds but is usually the most obscured by the vast landslides which have occurred in front of the escarpment. About 75 feet of massive grits with some flagstones probably occur beneath the lower seam, while 25 feet of rusty arenaceous shales with ironstone nodules, followed by 50 feet of massive grit, overlie the upper seam. It is clear that a great influx of fairly coarse arenaceous material entered the Namurian P. J. YATES: NAMURIAN OF SLIEVE ANIERIN 373 seas in the area at this time, associated with advancing delta fronts which periodically allowed a coal swamp vegetation to flourish. (g) Cravenoceratoides edalense and Ct. bisati fauna ( E2b\ ). The first fossiliferous horizon above the grit is exposed at L21(9)20, which is the nearest exposure to the top of the grit escarpment on the south-eastern side of Slieve Anierin; the intervening beds, about 40 feet thick, are obscured. At L21(13)3, on the south of the mountain where the grit is obscured by drift, the fossiliferous beds occur above 20 feet of unfossiliferous shales, the remainder being concealed. The horizon is about 8 feet thick and consists of dark-grey to black shales which split into large regular slabs. The number of species is low but individuals are abundant. The commonest species is Ct. edalense. This is the first appearance of Cravenoceratoides, which is closely related to Cravenoceras, a frequent member of the faunas at lower horizons and which still continues to flourish at this level. Associated with Ct. edalense, but much more rare, is Ct. bisati; it shows an irregular and repeated bifurcation of the lirae instead of the single division seen in Ct. edalense s.s. No specimens of Eumor- phoceras were seen at this level. The only other members of the fauna are P. corrugata and P. corrugata elongata subsp. nov. ; the latter was also common in the high E2a faunal band beneath the grit. This horizon is believed to be in the Ct. bisati subzone (the lowest subzone of the Ct. nitidus zone) although it is here dominated by Ct. edalense, and Ct. bisati itself is only a rare member of the fauna. In the absence of evidence for precise dating, the shales above L21(13)4 and L21(5)ll, the grit formation and the 40 feet of beds between the grit and the Ct. edalense band, can only be loosely assigned to either the top of the E. bisulcatum s.s. zone or the Ct. bisati subzone. (/?) Cravenoceras subplicatum fauna ( E2b\ ). The succession from the level of Ct. edalense to the summit of Slieve Anierin is exposed in its entirety in Valley 4 (L21(9)23). How- ever, better collections can be made in Valley 3 (L2 1(9)24), despite the fact that the succession is slightly less complete, beginning higher at the level of E. bisulcatum leitri- mense subsp. nov. The succession from Ct. edalense to E. bisulcatum leitrimense will therefore be described from Valley 4, and the rest of the succession from Valley 3 (see Table 2). The Ct. edalense beds are succeeded by 8 feet of shales in which specimens are so abundant at certain levels that individual outlines become obscured. At other levels sediment is more abundant and the details of the fauna are consequently less obscure. Some of the best examples of P. corrugata s.s. have been collected at these levels, associated with Posidoniella variabilis and P. variabilis erecta subsp. nov. This is the first appearance of Posidoniella in the area. The goniatites at this level belong to the genus Cravenoceras. At first the writer was inclined to assign these specimens, which are by no means good, to the eow/ingense group, but many of the better ones are now compared with C. subplicatum. The fauna undergoes a change in the succeeding 2 feet of beds. It is still a goniatite- lamellibranch fauna but now Dimorphoceras is the only goniatite. The difficulty of identifying the species of this genus without sutural evidence has already been men- tioned, and the specimens at this level are therefore only tenatively attributed to Dimor- phoceras cf. D. looneyi. This form dominates the fauna, and the only other fossils are 374 PALAEONTOLOGY, VOLUME 5 table 2. Distribution of goniatites and lamellibranchs in the subzones of Cravenoceratoides bisati and Cravenoceratoides nitidus on Slieve Anierin, compiled from Valleys 3 and 4, L21(9)24 and 23. P. J. YATES: NAMURIAN OF SLIEVE ANIERIN 375 Posidoniella variabilis and P. variabilis erecta subsp. nov., both of which were present at the lower level but subordinate to Posidonia. Above this band there are about 4 feet of shales which are virtually barren except for very infrequent narrow seams of P. corrugata indistinguishable from those at lower levels, and occasional specimens of A. tenuispirale. The succeeding 12-15 feet of shales are completely barren, but they are overlain by a very fossiliferous band about 9 inches thick, crowded with fossils which frequently obscure each other. P. corrugata and P. corrugata gigantea subsp. nov. abound, but P. corrugata elongata subsp. nov. is slightly less common. Poorly preserved goniatites are present, and as in the case of the lower forms they are assigned to C. subplicatum. In summary, the succession up to this point consists of about 16 feet of shales during the deposition of which a population rich in individuals but poor in species flourished. In the succeeding 2 feet Dimorphoceras , believed to be indicative of more brackish con- ditions, is the only goniatite. Thereafter, through about 16 feet of beds, conditions were unsuitable for goniatites, except for stray specimens of Anthracoceras and a few lamel- libranch seams at the base. Overlying this portion of the succession is another fos- siliferous horizon. (/) Eumorphoceras bisulcatum leitrimense fauna ( E2b2 ). The description of the succession from this horizon to the top of Slieve Anierin is continued from Valley 3 (L21(9)24). E. bisulcatum leitrimense subsp. nov. extends through about 18 inches of sediment, and is associated with abundant specimens of P. corrugata s.s., its two subspecies elongata and gigantea, and less common examples of Posidoniella variabilis. The specimens of Eumorphoceras are mostly rather small and are not usually so well preserved as the forms occurring below the grit, and also at higher levels than leitrimense. This band is a very useful marker horizon and collections have been made from it at several other localities; it is thought that it may in fact represent the base of the Ct. nitidus subzone. At L21(9)19 E. bisulcatum leitrimense has been collected with very scanty pieces of Cravenoceratoides ornament, but the lirae on these fragments, although showing the bifurcations seen in the lower Ct. edalense s.s. material, are asymmetrical as in the two species Ct. nitidus and Ct. nititoides. (j) Anthracoceras tenuispirale fauna ( E2b2 ). The E. bisulcatum leitrimense horizon is followed by 19 feet of shales, the only goniatite being Anthracoceras tenuispirale. This species has not hitherto been recorded in the British area but it occurs in abundance on Slieve Anierin. I am also informed by Dr. J. S. Jackson (in lift.) that the same species occurs in the Kingscourt inlier, Co. Meath. The possibility that specimens of A. tenuispirale from other areas have been wrongly identified as Cravenoceras cf. C. holmesi is discussed on p. 395. On Slieve Anierin A. tenuispirale is usually associated with Posidoniella variabilis and P. variabilis erecta subsp. nov. It may also have been the species present with E. bisulca- tum leitrimense but the material at this level is not sufficiently clear. Throughout the lower 5 feet of this 19-foot thickness of shales the proportion of fossils to sediment is about the same as in the lower leitrimense band so that individual specimens do not obscure each other; the lithology varies from pale brown decalcified siltstone to an intensely black siltstone. In the next 7 feet of shales within the 19-foot sequence, fossils are very rare except for 376 PALAEONTOLOGY, VOLUME 5 a few specimens of A. temiispirale and Lingula sp. Bisat (1933, pp. 412-14) believes Anthracoceras to be a semi-estuarine genus, and its scanty occurrence with Lingula here supports this contention. In the lower part of this 7-foot section P. variabilis is also present with A. tenuispirale , and seems to have been capable of withstanding a lower salinity than Posidonia. After this barren interlude there is a thickness of about 2 ft. 6 in. in which P. corrugata and P. corrugata elongata are dominant, and A. tenuispirale and Posidoniella variabilis both rare. There follow two white sandstone bands, each about 4 inches thick and separated by about 8 inches of sandy unfossiliferous shales. This brief arenaceous in- terlude is succeeded by about 2 ft. 9 in. of beds in which A. tenuispirale is the only fossil present apart from internal moulds of minute mollusca and impressions of conodonts. In the upper 9 inches Posidoniella variabilis and P. variabilis erecta appear again. Con- ditions during the deposition of these 19 feet of shales therefore obviously fluctuated from semi-estuarine to littoral. At no point in the succession were clay-ironstone bands observed. (k) Cravenoceras holmesi fauna (E2b2). Succeeding these 19 feet of shales is a 15-inch band dominated by C. holmesi. At L21(9)13 a few internal moulds of this form were collected just below the E. bisulcatum leitrimense material but at 1,21(9)24 it appears for the first time as a very abundant component of the fauna about 20 feet above leitri- mense. Associated with this species are very rare specimens of A . tenuispirale and a few rare P. variabilis erecta. C. holmesi persists through the overlying 2 ft. 6 in. of shales and at certain levels is very abundant, but at other levels A. tenuispirale is dominant. At those levels at which Cravenoceras abounds specimens of P. corrugata and P. corrugata elongata are also common. A. tenuispirale occurs mostly in isolation, although sometimes in association with conodont impressions. The next 3 feet of sediments are barren apart from rare A. tenuispirale and Lingula sp. ; the upper 6 inches of this section has yielded no fossils at all. A narrow sandstone band then occurs, followed by 9 feet of beds containing Lingula sp., a narrow sandstone band and then 2 feet of shales with obscure lAnthracoceras and Posidoniella and plant fragments only. (/) Cravenoceratoides nititoides fauna ( E2b3 ). These less interesting deposits are termin- ated by a 6-inch band of decalcified mudstone in which fossils, though exceedingly abundant, are poorly preserved. This band, however, is the prelude to more rewarding material since it immediately underlies the richest faunal horizon on Slieve Anierin. The latter is only about 9 inches to 1 foot in thickness but the individuals are more abundant and there is less sediment than in the leitrimense band. The band is tough, pale brown in colour, completely decalcified, and loose slabs are frequently found in the streams wind- ing through the peat on the upland area above the grit in front of the four main valleys on the south-western face of the mountain (text-figs. 1, 3). The fauna consists of Eumorphoceras rostratum sp. nov., Ct. nititoides, rare Ct. nitidus, Euchondria aff. E. levicula, Cliaenocardiola footii, C. cf. C. lialiotoidea, Dun- barella atf. D. elegans, Posidoniella cf. P. vetusta (Sowerby), Weberides cf. W. shun- nerensis, Productus hibernicus, Orbiculoidea nitida, Mourlonia striata, Archaeocidaris urii, crinoidal debris, Stroboceras subsulcatus, Fenestella sp., Edestodus sp. P. J. YATES: NAMURIAN OF SLIEVE ANIERIN 377 This is the richest and most diverse band in the succession in terms of species present. Trilobites, brachiopods, gastropods, and echinoid plates and spines only occur else- where in the sequence in P2 or very low Ex levels. This is the only level at which any bryozoa have been seen. After the accumulation of the thick grit formation the succession on Slieve Anierin up to the band just described has oscillated from decidedly marine horizons (e.g. those with Ct. edalense, C. subplicatum, and C. holmesi ) to beds deposited under far more brackish-water conditions with Dimorphoceras or Anthracoceras alone at certain levels or associated with Posidoniella variabilis. Between the grit and the Ct. nititoides band clay-ironstones have not been observed but there are several thin sandstone horizons with A. tenuispirale, particularly in the brackish sequences. Overlying the Ct. nititoides band there are 40 feet of barren sandy shales with clay- ironstone bands becoming more numerous towards the top. This is virtually a return to the lithology typically seen separating the various fossiliferous beds below the grit. The clay-ironstone horizons both below the grit and above the Ct. nititoides band occur as thin continuous beds as well as bands of nodules. The last solid beds seen under the peat deposits which cover the top of Slieve Anierin consist of about 12 feet of white or pale-buff flagstones with plant fragments. SYSTEMATIC DESCRIPTIONS Order ammonoidea Zittel 1884 Suborder goniatitina Hyatt 1884 Superfamily goniatitacea de Haan 1825 Family goniatitidae de Haan Subfamily girtyoceratinae Wedekind Genus eumorphoceras Girty 1909 Genotype: Eumorphoceras bisulcatum Girty 1909. In his diagnosis of this genus Moore (1946, pp. 417-18) includes the following fea- tures: pronounced ribs as early as the second whorl and continuing into the late youth- ful stage; a ventro-lateral groove; a generally rounded venter; and a ventro-lateral salient and ventral sinus. In his original description Girty (1909, pp. 67-68) defined Eumorphoceras as lacking constrictions; however, species and subspecies have sub- sequently been described which show constrictions. Moore (1946, p. 393) has commented on this and added this feature to his diagnosis of the genus (p. 418), which now therefore includes some taxa with constrictions. Eumorphoceras pseudo cor onula Bisat Plate 51, fig. 1 Eumorphoceras pseudocoronula Bisat 1950, p. 19, pi. 2, fig. 4. Description. The umbilicus is widely open. There are prominent constrictions which after a short radial passage from the umbilicus soon curve smoothly forward to pass obliquely into the ventro-lateral groove. The edges of the constrictions are sharp and raised into ribs. Between each pair of constrictions there appear to be two or three ribs 378 PALAEONTOLOGY, VOLUME 5 which are strongly seen in the umbilical edge and close to it, but which fade some dis- tance before the groove. The umbilical edge is beaded. The groove on the ventro-lateral area is divided into two by a strongly rounded ridge. The test ornament of delicate striae is seen in some specimens, and their course follows that of the constrictions as far as the groove. At the groove these striae have a prominent lingua, from which they curve backwards to a sinus on the venter. There are spiral striae in the ventro-lateral region. Localities. This species is a very common member of a rich fauna at L24(l)l and at L21 (14)8. Horizon. It is associated with Cravenoceras leion and Eumorphoceras rota (Yates 1961, pp. 57-58, pi. 6, figs. 6, 7). The stratigraphical level is Exa. Discussion. Although this form has already been described by Bisat, a description of the forms collected on Slieve Anierin is given here to facilitate comparison with the later closely related form of E. medusa (Yates 1961, pp. 54-56, pi. 6, figs. 1, 2). Specimen 7213 has been figured (op. cit., pi. 6, fig. 3). Eumorphoceras pseudobilingue A Bisat Plate 51, fig. 2; Plate 53, fig. 6 Eumorphoceras pseudobilingue A Bisat 1928, pi. 6 (facing p. 130). Description. This form is sharply ribbed with a wide umbilicus and in this material no evidence of constrictions has been seen. The ribs are numerous and sharp; they are sickle-shaped and separated by wide interspaces; close to the shoulder ridge they have a well-marked and smoothly-curved forward swing and pass into the ventro-lateral furrow. The umbilicus has a raised and beaded edge. The ventro-lateral furrow is divided into two by a well-marked ridge. Both the two resulting furrows are well defined. The specimens with shell preserved show fine striae which follow the rib direction; spiral striae are strongly developed in the region of the ventro-lateral ridge. Dimensions. 7016 (pi. 1, fig. 2): diameter 22 mm. ; umbilical diameter 7 mm. 7017 (pi. 3, fig. 6): diameter c. 35 mm.; the ribbing is still strong on this large specimen though it is becoming more indistinct on the last visible piece of whorl. Locality and horizon. The best examples on Slieve Anierin occur at L23(4)7. E. pseudobilingue A is associated with equally abundant examples of C. leion and is therefore an Exa species. Discussion. Moore (1946, p. 426) points out that although Bisat (1928) has divided E. pseudobilingue into three forms, A, B, and C, he has given no statement as to their differences, but apparently groups form A with C. leion. Moore also describes a form which seems to agree with one seen in younger beds on Slieve Anierin and it is therefore EXPLANATION OF PLATE 51 All specimens are from Slieve Anierin, Co. Leitrim, Eire. Fig. 1. Eumorphoceras pseudocoronula Bisat. 7015c. External mould; also showing two internal moulds of E. rota Yates (701 5a, b), X 3-5. Fig. 2. Eumorphoceras pseudobilingue A Bisat. 7016, external mould showing spiral ornament on the ventro-lateral ridge, X 4. Figs. 3-5. Eumorphoceras pseudobilingue (Bisat) emend. Moore. 3, 7039, showing wavy nature of nar- row ribs, X 3-6. 4, 7037, X 3-6. 5, 7040, showing angular beaded venter of large specimen, X 2. Palaeontology , Vol. 5 PLATE 51 2x4 5x2 YATES, Namurian goniatites P. J. YATES: NAMURIAN OF SLIEVE ANIERIN 379 useful and appropriate to describe the earlier form which agrees well with those figured by Nevill (1957, pi. 22, figs. 1-3) from the Summerhill Basin. Eumorphoceras pseudobilingue (Bisat) emend. Moore 1946 Plate 51, figs. 3-5 Glyphioceras pseudobilingue Bisat 1922, The Naturalist, pp. 225-6. Eumorphoceras pseudobilingue (Bisat) partim. Bisat 1924, pp. 99-100, pi. 10, figs. 1, 2. Eumorphoceras pseudobilingue (Bisat); Schmidt 1934, p. 446, fig. 1. (non) Eumorphoceras pseudobilingue (Bisat); Demanet 1941, pp. 135-6, pi. 5, figs. 11-14. Eumorphoceras pseudobilingue (Bisat) emend. Moore 1946, pp. 426-9, pi. 23, fig. 2; pi. 25, fig. 3; text-fig. 27. Description. The very early whorls have not been seen. At 12 mm. diameter the ribbing is strong and there are about 13/half whorl. The following description is based on many specimens of which 7037 (PI. 51, fig. 4) is a typical example. At c. 20 mm. there is a ventro-lateral ridge and a wide umbilicus. The venter is broad but the mid-venter becomes raised and angular. It is not certainly known at what diameter this angularity of the mid-venter appears, but it is a well marked character by c. 25 mm. Large frag- ments show a distinct notching of the mid-ventral ridge (PI. 51, fig. 5). The ribs in this species have a typically wavy character. In the adult whorl they are thin and sharp, separated by wide interspaces. In the earliest part of the whorl they are sharp on the umbilical edge and continue over the greater part of the flank. Near the ventro-lateral ridge they curve forward and terminate at the ridge. At this stage there is one quite noticeable bend in the course of the ribs close to the umbilical edge. As the whorl advances the ribs fade over most of the flank and are sharp only in the immediate neigh- bourhood of the umbilicus. They swing strongly forward just after leaving the umbilical edge but then disappear. At very advanced diameters there are still indications of the ribs at the extreme umbilical edge, and they persist when the ventro-lateral ridge has all but disappeared. Dimensions. 7037 : diameter c. 20 mm. (PI. 51, fig. 4). 7038 : diameter c. 25 mm. Most of the specimens approximate to these dimensions but crushing has obscured many, making their exact measurement impossible. Localities. L23(4)l and L2 1(5)4. Horizon. L23(4)l is isolated but is probably in low Ejb. At L21(5)4, which is also in low Eib, the fauna occurs a little distance above beds with Eumorphoceras cf. E. angustum, Posidonia corrugata, and P. trapezoedra ; the latter horizon is separated by a considerable thickness of unfossiliferous rusty shales from the highest faunal band in the C. leion zone (E^). Discussion. The Slieve Anierin examples are considered to conform to the lectotype (GSM 72972) from Little Mearley Clough described by Moore (1946), and other speci- mens deposited by Moore at the Geological Survey Museum from Cow Close Syke, Malham. Moore gives no stratigraphical placing beyond assigning an Ex age. A few feet above this form on Slieve Anierin occur forms referred to Cravenoceras aff. C. malham- ense, Kazakhoceras scaliger, and CaneyeUa membranacea. The figure given by Schmidt (1934, p. 446, fig. 1) shows a similarity in the wavering nature of the ribbing and the ridge which develops in the mid-venter. Demanet (1941, pp. 135-6, pi. 5, figs. 11-14) has forms which do not resemble either the Irish specimens or Moore’s material. They 380 PALAEONTOLOGY, VOLUME 5 apparently have a far smaller umbilicus, the ribbing disappears at far smaller diameters and there is apparently a strong shoulder groove. These specimens do not resemble Eumorphoceras pseudobilingue A. Eumorphoceras pseudobilingue C Bisat Plate 52, figs. 1, 2 Eumorphoceras pseudobilingue C Bisat 1928, pi. 6. Description. There is a marked groove on the ventro-lateral area which persists to ad- vanced diameters. At 10 mm. diameter (umbilical diameter 3 mm.) there are ribs which are strongly defined at the umbilical edge but which lose their strength over the flanks. In their thinness and wide interspacing they resemble those of E. pseudobilingue s.s., but lack the typical wavering character of the ribs in that species although they still show a kink near the umbilical edge. At this stage there are slight constrictions. By 1 5 mm. diameter the ribs are seen only at the extreme umbilical edge and no constrictions are seen. The ventro-lateral groove is still strong. Dimensions. 7041 : diameter 15 mm. (PI. 52, fig. 1). 7042: diameter 10 mm. (PI. 52, fig. 2). 7043: dia- meter c. 8 mm. 7044: diameter c. 10 mm. Localities. L21(5)4, low Exb; L2 1(1 3)8, high Ejb. Horizon and associated fauna. These forms have all been collected from a very thin band immediately above beds with E. pseudobilingue s.s., which are in turn above beds containing Eumorphoceras cf. E. angustum. They are associated with rare specimens of Chaenocardiola footii and gregarious small individuals of Posidonia corrugata. Discussion. This species has points of similarity with E. angustum Moore (1946, pp. 424- 6, pi. 24, figs. 1-7; text-fig. 26), namely the early fading of the ribs and the compara- tively small umbilicus; however the ribs, although fading early, are still quite strong at diameters at which in E. angustum they are little more than plications. In E. pseudo- bilingue C there is an undoubted groove in the ventro-lateral area which contrasts strongly with the poorly developed ridge seen in this area in E. angustum. A large distorted specimen at about 22 mm. diameter still shows the ventro-lateral groove. A comparison has also been made with E. hudsoni Gill, originally described by Moore (1946, pp. 419-20, pi. 24, figs. 2, 2a) as Eumorphoceras sp. form B aff. Sagittoceras costatum Ruprecht. Moore states that in this species the groove in the ventro-lateral EXPLANATION OF PLATE 52 All specimens are from Slieve Anierin, Co. Leitrim, Eire. Figs. 1, 2. Eumorphoceras pseudobilingue C Bisat. 1, 7041, showing early loss of ribs and strong ventro-lateral groove, X5-5. 2, 7042, x6. Figs. 3, 4. Eumorphoceras bisulcatum grassingtonense Dunham and Stubblefield. 3, 7047, the inner whorls show rib bifurcation and a relatively early reduction in their strength; the outer whorl is preserved as an internal mould showing a strong groove only, X 5-3. 4, 7046, fragment showing two constrictions, X 7. Fig. 5. Eumorphoceras bisulcatum ferrimontanum subsp. nov. 7055, paratype, showing ribs only at the umbilical edge, merging into finer striae over the flanks, X 4. Fig. 6. Cravenoceratoides nitidus (Phillips). 7094, external mould showing relatively large umbilicus and asymmetrical lirae, x 4. Palaeontology, Vol. 5 PLATE 52 YATES, Namurian goniatites P. J. YATES: NAMURIAN OF SLIEVE ANIERIN 381 area continues up to about 20 mm. On the holotype (GSM 72650) at 1 1 mm. diameter there appears to be very little sign of a groove, but only a slight ridge. This ventro- lateral groove does not appear as a very strong feature on GSM 72649, 72651-5, all collected from Carla Beck, near Skipton. E. pseudobilingue C has a strong groove, and a smaller umbilicus than E. hudsoni. The Slieve Anierin specimens are, however, similar to E. pseudobilingue s.s. The thin ribs with wide interspaces are common to both but in E. pseudobilingue C the ribs fade earlier and do not show the wavy character seen in the ribs of E. pseudobilingue s.s. The ribs (see 7041, PI. 52, fig. 1), before fading on the flanks, show the same kink after leaving the umbilicus as is seen in E. pseudobilingue s.s. In the latter, however, there is a definite ridge in the ventro-lateral area. Bisat has mentioned but never described or figured E. pseudobilingue C (1928, pi. 6). Slieve Anierin forms have so far been referred to E. pseudobilingue A and to E. pseudobilingue s.s. At the Geological Survey Museum GSM Z1 5777, collected in Little Mearley Clough, has been labelled E. pseudobilingue C, but the specimens are very poor though they appear to possess a groove on the ventro- lateral area. There are also slabs collected by Parkinson from Studforth Gill, Tosside, 5 miles south-west of Settle, Yorkshire, which are said to be high E. pseudobilingue C. On these slabs only one specimen, GSM Z1 5775, resembles the Slieve Anierin examples; although poor it has a groove on the shoulder. On the other slabs the examples appear to be closer to E. pseudobilingue s.s. It has been decided (with Bisat’s approval, in lift.) to refer these examples from Slieve Anierin below Cravenoceras malhamense to E. pseudobilingue C. Eumorphoceras bisulcatum grassingtonense Dunham and Stubblefield Plate 52, figs. 3, 4 Eumorphoceras bisulcatum Girty mut. grassintonensis Dunham and Stubblefield 1944, pp. 258-60, pi. 11, figs. 4 a-c. Description. At a diameter of about 10 mm. the umbilical diameter is about 3-5 mm. ; in 7045 at this diameter there are about fourteen strong ribs in slightly under half a whorl ; these ribs are strong and slightly swollen at the umbilical edge, where they seem to project over the edge; there are two clear constrictions in this specimen. At a diameter of about 7 mm. 7046 shows one clear constriction and a rib forking very close to the umbilical edge just before the constriction. In 7047 at 12 mm. diameter the ribs show raised, swollen tips at the umbilical edge but they are very muted across the rest of the flank; at 19 mm. diameter over the flank (which is all this specimen shows at this dia- meter) only growth lines are seen. At this, the largest diameter seen, the shoulder groove is still strong. From above these constrictions are not very strong; they are most easily seen at their break into the shoulder groove. This is also true in the type specimen GSM KD423. This feature is also commented on by Currie (1954, p. 582) in describing E. bisulcatum aff. grassingtonense Dunham and Stubblefield. Dimensions. 7047: greatest diameter 19 mm., diameter of inner ribbed part 12 mm. (PI. 52, fig. 3). 7046: diameter 7 mm. (PI. 52, fig. 4). 7045: diameter 10 mm. Localities. L21 ( 1 3)6 and L21(5)8. Horizon. Low E,a. This is the earliest record on Slieve Anierin of E. bisulcatum. It occurs very scantily 382 PALAEONTOLOGY, VOLUME 5 indeed, the dominant goniatite at this level being Cravenoceras cowlingense. Dimorphoceras sp. is also present. Lamellibranchs are not common and include Chaenocardiola footii, Posidonia lamellosa and P. corrugata. Discussion. The material at this level is very scanty and Cravenoceras individuals far exceed Eumorphoceras in abundance, but as this is the lowest horizon at which E. bisulcatum occurs they are particularly important specimens. At 10-5 mm. diameter grassingtonense, described by Dunham and Stubblefield (1944, pp. 258-60), has an umbilicus of 4-0 mm. and about sixteen ribs in half a whorl. Specimen 7048 corresponds approximately to these figures ; only two constrictions have been seen in this specimen but others may be concealed between these two. 7046 shows a bifurcation of the ribs at a point immediately before the single clear constriction. Rib bifurcation is a feature of grassingtonense, in which at 10-5 mm. diameter there are about five constrictions with five ribs between them, but the number is not constant. The ribs of grassingtonense are said to ‘take origin at the margin in a raised tubercle’, and this feature is seen in the Sheve Anierin material. In the original description of this mutation it is stated that the diameter at which the ribbing becomes reduced is not known. In 7047, at about 12 mm. diameter, the ribs are still strong at the edge of the umbilicus but less apparent on the flank. At this diameter also bifurcations in the ribs appear to be slightly commoner and to take place further over the flank. Eumorphoceras bisulcatum erinense subsp. nov. Plate 53, figs. 1,2; Plate 54, fig. 7 t Description. The ribs are strong and numerous. They continue across the flanks almost to the shoulder groove; very close to the latter they bend forward rather sharply. After a short oblique passage forward they end at the groove. The ribs are still apparent at a diameter of 14 mm. in 7049 and the umbilical diameter is about a third of the total diameter. In some specimens the ribs are still strong at 18 mm. over most of the flank (see 7050) and the shoulder groove is also still strongly defined. Holotype. 7049 c (counterpart 7274): the large specimen, diameter 14 mm. (PL 53, fig. 1). Paratypes. 7049 a, b : two small specimens on the same slab, diameter 8 mm. and 9 mm. (PI. 53, fig. 2). 7050 : diameter 17-18 mm. (PI. 54, fig. 7). 7052: diameter 12 mm. Type locality and horizon. This subspecies has so far only been collected from one locality, L21(5)10, which is thought to be very close to L21(13)4 and L21(5)ll in stratigraphical level, which is high E2a. The associated fauna at the three localities is the same, and E. bisulcatum ferrimontanum subsp. nov. occurs at L21(5)10 with erinense, but less abundantly. At the other localities mentioned only ferrimon- tanum is present. EXPLANATION OF PLATE 53 Except for fig. 3, all specimens are from Slieve Anierin, Co. Leitrim, Eire. Figs. 1, 2. Eumorphoceras bisulcatum erinense subsp. nov. 1, 7049c, holotype, showing geniculate aspect of ribs, X4-3. 2, 7049u, b, paratypes, external moulds, x4. Fig. 3. Eumorphoceras cf. E. bisulcatum ferrimontanum subsp. nov. Edge Marine Band, Cononley Beck, 200 yds. S. 47° W. of Cononley Church, Yorks. GSM GM3675, X4-25. Figs. 4, 5. Eumorphoceras bisulcatum leitrimense subsp. nov. 4, 7060, holotype, showing constrictions. with 2-3 short intervening ribs, X 5-3. 5, 7063, paratype, X 9-4. Fig. 6. Eumorphoceras pseudobilingue A Bisat. 7017, external mould, x3. Palaeontology, Vol. 5 PLATE 53 YATES, Namurian goniatites P. J. YATES: NAMURI AN OF SLIEVE ANIERIN 383 Discussion. This subspecies resembles E. bisulcatum ferrimontanum subsp. nov. in some respects. Both forms have abundant and strong ribs, but in erinense they persist to much larger diameters. The groove is strong to large diameters in both subspecies. Apart from the greater persistence of the ribs in erinense there is also a difference in their appearance when compared with those of ferrimontanum. In erinense they pass almost to the groove before bending forward rather sharply to pass obliquely into the groove. The result is a geniculate appearance and a larger radial portion to the rib. In these specimens of erin- ense although the ribs persist to about 18 mm. diameter they merge distally into the finer striations on 7049c where the geniculation begins at about 14 mm. diameter. In 7050 they are strong over about three-quarters of the flank and then degenerate. At a diameter of at least 25 mm. 7053 has a marked ridge at the shoulder with a slight furrow on its lateral and ventral side. As with ferrimontanum there are differences when com- pared with E. bisulcatum Girty s.s. The geniculate aspect of the ribs in erinense is closer to Girty’s figures than the ribs in ferrimontanum. Occasional indications of rib bifurcation are seen in erinense but these do not seem to follow any definite pattern. They are not mentioned in Girty’s description (1909, pp. 68-70) nor by Miller and Youngquist (1948, pp. 662—4). The umbilicus of the type specimen of E. bisulcatum s.s. is smaller than that seen in erinense. Eumorphoceras bisulcatum ferrimontanum subsp. nov. Plate 52, fig. 5; Plate 53, fig. 3; Plate 54, figs. 1-4 Description. Most of the specimens are rather small. The ribs are strong from the earliest whorls. By the time a diameter of 12 mm. has been reached the ribs are sharp on the immediate umbilical edge only. At smaller diameters the ribs pass over the flanks with a slightly forward trend towards the shoulder groove. They have a slight twist at the um- bilical edge. Close to the groove they curve forward and are much less distinct, merging into finer growth striae. They pass forwards to form a lingua in the ventro-lateral region. The rounded termination of the lingua is situated on the ventral side of the shoulder groove. There are indications also of spiral ornament in this region. The shoulder groove is seen to advanced diameters (see 7054 and 7055). The groove is strong, with the inner and the ventral wall showing about equal angles of slope. At a radius of 15 mm. 7056 shows a ridge at the shoulder with a strong furrow still on its lateral side and a far fainter furrow on the ventral side. So far no undoubted constrictions have been seen in these specimens. The umbilical diameter is about a third of the total diameter at 14 mm. diameter. The ribs in 7057 number about 17/half whorl. There is evidence of at least nine ribs in the small fragment of the umbilicus seen in 7055. Holotype. 7054 (counterpart 7048): diameter 18 mm. (PI. 54, fig. 1). Paratypes. 7058: incomplete, 727 mm. (PI. 54, fig. 2). 7059: diameter 11 mm. (PI. 54, fig. 3). 7055 (PI. 52, fig. 5). 7057: diameter 14 mm. (PI. 54, fig. 4). Type locality and horizon. This form is abundantly represented on Slieve Anierin at L21(13)4, the type locality, and at L21 (5) 1 1 . The horizon is high E2a. The rich associated fauna includes Cravenoceras cf. C. gairense, Kazakhoceras scaliger, Chaenocardiola footii, Dunbarella elegans, and several varieties of Posidonia corrugata. Discussion. In this form the ribs apparently fade away relatively early. 7058 is almost smooth apart from the growth-lines and the faint indication of ribs at the umbilical 384 PALAEONTOLOGY, VOLUME 5 edge. The lingua is relatively deep (see 7055 and 7054). The rib counts are fairly large. These examples are obviously broadly referable to E. bisulcatum Girty. Unfortunately Girty’s description (1909, pp. 68-70, p. 1 1, figs. 1 5— 19c) is based on specimens of about 10 mm. diameter and the later stages well seen on the Slieve Anierin specimens have not been discussed in detail beyond the statement that the ventro-lateral groove persists for longer than the ribs. From Girty’s plates it seems that his specimens apparently have rather more geniculate ribs than are seen in the author’s material. Moore (1946, pp. 430-3) describes a form which he refers to E. bisulcatum Girty s.l. but it does not agree with the present subspecies. The latter is probably close to the form E. bisulcatum as described by Girty, but differs in the less geniculate nature of the ribs. Most of the Irish specimens have an umbilical diameter of about a third of the total diameter. The type specimen of E. bisulcatum (refigured by Moore 1946, pi. 25, figs. 5 a-d) has an umbilical diameter of about 25 per cent of the whole. The inability to compare very closely the specimens at slightly more advanced stages is also a difficulty. However, since this form occupies a definite level and appears to be distinct in at least one feature it is proposed to name it E. bisulcatum ferrimontanum. Subspecies of E. bisulcatum. The three subspecies of E. bisulcatum which have been described may look very similar superficially but a study of many specimens collected from beds whose order of superposition is known with certainty is valuable and shows that three subspecies of this species do exist. Two of these occur on approximately the same level and are stratigraphically higher than the third. For the sake of clarity the salient features of these three subspecies and their order of appearance are summarized. (a) Specimens collected at L2 1(1 3)6 and L2 1(5)8 from a low E2a horizon show: 1 . About sixteen ribs in half a whorl. 2. Constriction (at least at small diameters). 3. Rib-bifurcation (more frequent at advanced diameters and taking place farther from the umbilical edge). 4. Ribs which are somewhat swollen at the umbilical edge and project over it. 5. Ribs fading over the flanks at 12 mm. diameter. 6. An umbilical diameter which is about 35 per cent of the whole. 7. The groove still strong at the largest diameter seen. These are identified as E. bisulcatum grassingtonense. ( b ) The high E2a band at L21 (5) 1 0 yields specimens attributable to a subspecies showing: 1. Geniculate ribs. 2. Ribs still apparent at 17-18 mm. EXPLANATION OF PLATE 54 All specimens are from Slieve Anierin, Co. Leitrim, Eire. Figs. 1-4. Eumorphoceras bisulcatum ferrimontanum subsp. nov. 1, 7054, holotype, external mould showing early failure of ribs, and spiral ornament on the ventro-lateral area, X 3-75. 2, 7058, paratype, external mould, with the ventro-lateral groove still seen over most of the specimen although the ribbing has been lost, X 3'3. 3, 7059, paratype, external mould, X 5. 4, 7057, paratype, external mould, X4-75. Figs. 5-6. Eumorphoceras bisulcatum leitrimense subsp. nov. 5, 7065, showing constrictions persisting over the venter, X 8. 6, 7064, paratype, X4-75. Fig. 7. Eumorphoceras bisulcatum erinense subsp. nov. 7050, paratype, showing geniculate ribs to relatively large diameter, X3-75. Palaeontology, Vol. 5 PLATE 54 YATES, Namurian goniatites P. J. YATES: NAMURIAN OF SLIEVE ANIERIN 385 3. An umbilical diameter about 33 per cent of the whole. 4. Constrictions not apparent. 5. Occasional indications of rib bifurcation. 6. Groove persistent to advanced diameters. At very large diameters a ridge appears with a shallow groove laterally and ventrally. These are identified as E. bisulcatum erinense subsp. nov. Rare examples of the following subspecies are also present. ( c ) Specimens collected from the high E2a band at L21(5)ll and L21(13)4 show: 1. No bifurcations or constrictions. 2. An umbilical diameter which is about 33 per cent of the whole. 3. Ribs fading on the flanks at about 12 mm. 4. The groove persisting to advanced diameters ; at very advanced diameters there is a ridge at the shoulder with a strong groove laterally. 5. About seventeen ribs in half a whorl. These are identified as E. bisulcatum ferrimontanum subsp. nov. All these early examples of E. bisulcatum show features of resemblance to E. bisulcatum s.s. A close relationship exists between the three subspecies despite the several dis- tinguishing features which each has developed. The earliest subspecies, grassingtonense , resembles the much later ferrimontanum in the early fading of the ribs on the flanks, but no rib bifurcations and constrictions have been seen in the latter and the umbilical diameter may be slightly smaller in ferrimontanum at comparable diameters. Erinense and ferrimontanum are alike in umbilical diameter but the ribs persist to greater dia- meters in erinense and are rather geniculate in aspect. The latter shows an occasional rib bifurcation, a link with grassingtonense. All three subspecies in common have a strong shoulder groove persisting to the large diameters but at very large diameters in erinense and ferrimontanum a ridge appears on the shoulder. A strong furrow is present laterally of this ridge in ferrimontanum but there appears to be a less strong furrow each side of the ridge in erinense. Comparably large diameters of the lower form grassingtonense are not available for comparison. There is still a groove at c. 20 mm. in this subspecies. The distinguishing features are the relative persistence of the ribs, their aspect, and whether or not they show bifurcations. Constrictions have so far only been seen clearly in grassingtonense , the earliest form. Eumorphoceras bisulcatum leitrimense subsp. nov. Plate 53, figs. 4, 5; Plate 54, figs. 5, 6; Plate 55, fig. 5 Description. These specimens are all rather small. Constrictions are clearly seen. 7060 is the best specimen and shows in the earlier part of the last whorl three short ribs between the constrictions. Later there appear to be only two ribs between the con- strictions. The intermediate ribs are short and do not extend to the ventro-lateral groove. This groove is strong to advanced diameters. Fragments of shell devoid of all indications of ribs or constrictions are not uncommon and represent an extremely gerontic stage of this subspecies. The umbilicus is not large ; at small diameters it is about 29 per cent of the total diameter. A few short ribs persist at the umbilical edge after the last constrictions, and are rather fat and stubby. At least in the early stages the constrictions are strong over the venter; unfortunately the venter at later stages has not been seen. 386 PALAEONTOLOGY, VOLUME 5 Holotype. 7060: diameter 10 mm.; umbilical diameter 2-5-3 mm. (PI. 53, fig. 4). Paratypes. 7061: diameter 16 mm. (PI. 55, fig. 5). 7062: diameter 10 mm. 7063: diameter 5 mm. (PI. 53, fig. 5). 7064: diameter 7-8 mm.; umbilical diameter 1-5-2 mm. (PI. 54, fig. 6). Type locality and horizon. Basal beds at L21(9)27, western exposure. It also occurs in basal beds at L2 1 (9)28 and in Valley 3 (L21(9)24) and Valley 4 (L21(9)23). The E2b2 horizon on which this form oc- curs is above beds rich in Ct. edalense and well below the top faunal band. Associated with this form are several variants of Posidonia corrugata, and Anthracoceras cf. A. paucilobum. Discussion. From a consideration of specimens 7060 and 7064 it appears that in the last constrictions seen, there are only two intervening short ribs, of which either one or both coincide with the actual edge of the constriction, which is raised and rib-like close to the umbilicus. In the earlier part of the last whorl, which shows these intermediate short ribs, one of these, the first to develop, coincides with the edge of the constriction. The constrictions show a strong forward curve in all cases. Not many subspecies of E. bisulcatum with constrictions have been described. H. Schmidt (1934, p. 455) defines E. bisulcatum varicata; this form, at a diameter of 12 mm., has seven ribs reducing to four between the constrictions. The constrictions are shown on his figure (op. cit., p. 449, fig. 29) to continue strongly over the venter and the umbilicus looks quite large compared with the Slieve Anierin material. The short intermediate ribs are the same in both cases but in the German specimens there are greater numbers of intermediate riblets between the constrictions. E. bisulcatum grassingtonense Dunham and Stubblefield (1944, pp. 258-60) has con- strictions which number about five/whorl and usually have about five ribs between them. However these intermediate ribs are not short but geniculate, and reach to the ventro- lateral groove. Also there is occasionally the appearance of a bifurcation. The type specimen of this form does not show any constrictions over the venter and the form is obviously distinct from the Slieve Anierin material. The constrictions are less obvious in grassingtonense. The only form so far described which bears any resemblance to the author’s specimens is E. bisulcatum varicata, but the former can be distinguished by means of the very low number of intermediate riblets between the constrictions. The varieties of E. bisulcatum from the Scottish limestones (see Currie 1954, pp. 581-4, pi. 4, figs. 5-7) do not seem to resemble this subspecies. GSM Da 1593, 1594, and 1599, collected from a section in the left bank of the stream, 150 yards south-east of Low Stubbing and 820 yards N. 10° W. of Holy Trinity Church, Cowling, are thought to be the same as the Slieve Anierin form. EXPLANATION OF PLATE 55 All specimens are from Slieve Anierin, Co. Leitrim, Eire. Figs. 1-4. Eumorphoceras rostratum sp. nov. 1 , 7066, paratype, showing one rib bifurcation and the shal- low groove between the curve of the flank and the ridged edge of the venter, X 3-8. 2, 7067 a, holo- type, external mould, x3-5. 3, 1061b, paratype, x6. 4, 7068, paratype, X 3. Fig. 5. Eumorphoceras bisulcatum leitrimense subsp. nov. 7061, paratype, external mould showing persistent ventro-lateral groove but early loss of ribs and constrictions, X 4-6. Fig. 6. Cravenoceras leion Bisat. 7076, fragment of internal mould showing two constrictions and the acute edged umbilicus, x 4. Palaeontology , Vol. 5 PLATE 55 4x3 5 X 4-6 YATES, Namurian goniatites P. J. YATES: NAMURIAN OF SLIEVE ANIERIN 387 Eumorphoceras rostratum sp. nov. Plate 55, figs. 1-4 Description. These specimens are very strongly ribbed from the smallest diameters seen. The largest complete specimen at 27 mm. diameter still shows very strongly developed ribs. At 10 mm. diameter there are about eleven ribs in half a whorl. Occasionally a rib forks (e.g. in specimen 7066). At 18 mm. diameter there are about fourteen ribs in half a whorl. The ribs pass strongly and radially (with a forward trend) over the flank for about half to two-thirds of the distance between the umbilical edge and the shoulder groove. They then begin to curve forwards, and thereafter lose their strength and merge into growth lines which pass forwards into an extremely deep lingua over the strong ridge at the shoulder. There is a shallow concavity between the curve of the flank and the strong ridge which marks the junction of the curved flank and the venter (the venter is usually embedded but the ridge at the edge of the flank apparently passes straight down into, and is the edge of, the flattened venter). Holotype. 7067 a (counterpart 7211): diameter 27 mm. (PI. 55, fig. 2). Paratypes. 1061b (counterpart 7212): small specimen on this slab, diameter 10 mm. (PI. 55, fig. 3). 7066: diameter 20 mm. (PI. 55, fig. 1). 7068: diameter 20 mm. (PI. 55, fig. 4). 7069: diameter 20 mm. Type locality and horizon. Valley 4, L21(9)23 ; also Valley 2, L21(9)25. All the specimens were collected from a very prominent fossiliferous horizon which is the highest on Slieve Anierin, E,b3. They are members of a very abundant fauna which includes Ct. nititoides, Chaenocardiola footii, Weberides cf. W. shunnerensis, &c., and which occurs about 40 feet above E. bisulcatum leitrimense subsp. nov. Discussion. The distinguishing features of these specimens are the very pronounced lingua in the growth-lines ; the early merging of strong ribs into fine growth-lines which often takes place about half-way across the flank; the strong ridge at the junction of venter and flank; and the very shallow depression between this ridge and the gently curved flank. The ribs are still strong at large diameters. No constrictions have been seen. Moore (1946) has described specimens of E. bisulcatum s.l. from Samlesbury Bottoms, River Darwen, Lancs., where they are associated with Nuculoceras nuculum. They therefore occur at a higher horizon than the Slieve Anierin specimens. A study of Moore’s specimens in the Geological Survey Museum results in the conclusion that the forms are not the same. In GSM 72603 (Moore 1946, pi. 22, fig. 3) there is a definite groove at the shoulder and the ribs persist across the flanks to this groove. 7061b from Slieve Anierin is approximately the same size for comparison and is distinctly different. The strong ribs have merged into growth-lines and start their forward swing to the lingua about half-way across the flank ; also, there is no prominent shoulder groove but only a slight dip on the flank side of the sharp edge which lies between flank and venter. The test is seen in the specimens described by Moore and shows spiral lirae (GSM 72602, pi. 27, fig. 2). These have not been seen in the Slieve Anierin material, but the vagaries of preservation may well be responsible for this absence. A point of similarity is that the ridge (at the margin of the flank) which slopes down to the venter is also present in Moore’s material, but in the latter is flanked by a decided groove which is already present by 3 mm. diameter. Miller and Youngquist (1948, pp. 665-7, pi. 100, figs. 1-4, 20, 21) have defined the species E. plummeri, which they believe closely resembles the form described by Moore. C 674 c c 388 PALAEONTOLOGY, VOLUME 5 From their plate and descriptions the same distinctions from the Slieve Anierin speci- mens as those for Moore’s material are valid. Subfamily homoceratinae Spath Genus cravenoceras Bisat 1928 Genotype: Cravenoceras malhamense (Bisat 1924). Bisat originally defined this genus in 1928 but sub- sequently described it far more fully (1932, pp. 27-36, pi. 1, 2). Within the genus he separated two groups, one around forms like C. leion Bisat and C. malhamense (Bisat) with delicate non-dichotomiz- ing striae, and another group with stronger dichotomizing ornament and including such forms as C. edalense Bisat and C. nitidum (Phillips). Hudson (1941, p. 282, footnote) later separated off the latter group as a new genus, Cravenoceratoides, but left the other group as Cravenoceras. Cravenoceras cf. C. gairense Currie Plate 56, figs. 1, 2 Cravenoceras gairense Currie 1954, pp. 577-9, figs. 8-10; text-figs. 6b, c. Description. This form is interpreted as moderately globose. The umbilicus is not large and probably occupies about a quarter or less of the diameter. The ornament consists of fine non-bifurcating striae, having a distribution of three or four per 1 mm. at about 6 mm. from the umbilical edge. The striae are radial with a very slight forward trend from the umbilicus. There are three raised spiral ridges around the umbilicus; in the impressions they are seen in reverse as impressed furrows separated by low curved ridges. The spiral ridges are raised above the general curvature of the flanks to form a rim around the umbilicus. Dimensions. The specimens are generally too fragmentary for accurate measurement; the following are relatively complete, although squashed, specimens. 7082 (counterpart 7256): diameter c. 8 mm.; umbilicus 2 mm. 7083 (counterpart 7257): diameter c. 8 mm.; umbilicus 2 mm. (PI. 56, fig. 1). Localities and horizon. The specimens were all collected at localities L21 (1 3)4, L21 (5)1 1 , and L2 1 (5) 1 0, which are all thought to be at approximately the same stratigraphical level and represent a high E2a horizon. Discussion. This distinctive species has been described by Currie from the Gair Lime- stone of Lanarkshire, and other specimens from the Calmy Limestone of Lanarkshire are also mentioned. Currie (1954, p. 532) has given a table showing the possible strati- graphical relationships of the Scottish deposits, from which it appears that the Calmy Limestone and the Gair Limestone are both higher in E2 than the beds on Slieve Anierin EXPLANATION OF PLATE 56 All specimens are from Slieve Anierin, Co. Leitrim, Eire. Figs. 1, 2. Cravenoceras cf. C. gairense Currie. 1, 7083, X5-25. 2, 7084, fragmentary external mould showing spiral ornament around the umbilicus, X 5. Figs. 3, 4, 6. Cravenoceratoides cf. Ct. bisati Hudson. 3, 7103, showing irregular bifurcating lirae, X 4-5. 4, 7104, external mould showing repeated bifurcation of lirae, X 3-5. 6, 7105, external mould showing irregular bifurcation of lirae, X 4. Fig. 5. Cravenoceratoides edalense (Bisat). 7101, part of internal mould with a constriction, and an external mould showing the symmetrical lirae with one bifurcation, X 5-3. Fig. 7. Chaenocardiola footii (Baily). 7174, external mould, x 6-5. Palaeontology , Vol. 5 PLATE 56 YATES, Namurian goniatites and lamellibranchs P. J. YATES: NAMURIAN OF SLIEVE ANIER1N 389 are believed to be. The fauna associated with C. gairense in the Scottish limestones is rather similar to that which occurs at a higher level on Slieve Anierin within the Ct. nitidus zone E2b. Currie (in lift., 1959) admits the great similarity of the Irish material to her specimens but is unwilling to go any further with shale impressions only. The specimens are therefore probably best identified as Cravenoceras cf. C. gairense. Currie mentions a specimen in the Geological Survey Museum (GSM RM77) which resembles her species but apparently lacks the middle spiral line. In addition GSM JS1479 and JS1492 from Crickton, Glam., appear to be very close to C. gairense. GSM JS1121 from near Ilston, Glam., is also close. Cravenoceras subplicatum Bisat Plate 57, fig. 1 Cravenoceras subplicatum Bisat 1932, pp. 30-31, pi. 1, fig. 5. Description. The shape of these specimens is not easy to interpret but is apparently a slightly flattened cadicone. The ornament consists of very fine non-bifurcating striae, which are radial with no backward deflection near the umbilical edge. The umbilicus is about a quarter or slightly more of the total diameter. There are two noticeable features in these specimens. The first is seen on 7085, which shows the impressions of rather widely spaced striae over the venter and more sharply incised impressions of some of the striae at the umbilical edge. The other feature is seen on the internal mould 7086, which shows a tendency to form undulations of the surface which fan outwards from the umbilicus and fade away over the flanks and venter. Each of these undulations bears on its surface several striae, one of which usually appears somewhat more prominently than those on either side of it. Dimensions. All the specimens are small and imperfectly preserved, and it is difficult to give accurate dimensions; the diameters are considered to be from 10-14 mm. Localities and horizon. Most of the specimens have been collected from Valley 4, L21 (9)23, from an E2bl level between the Ct. edalense beds and beds with E. bisulcatum leitrimense subsp. nov. They are particularly common in a band just beneath that containing the latter. They are associated with Posi- donia corrugata and its subspecies. Less perfect examples have been collected from just above the Ct. edalense beds. Good specimens have been collected at localities L21(9)l— 14. Discussion. These specimens are very abundant and in view of their stratigraphical position it is important to decide on their affinities. They contrast with C. cowlingense Bisat (1932, pp. 29-30, pi. 1, figs. 1-3) in the absence of any backward deflexion in the ornament ; also the ornament is rather finer (at any rate at these diameters though pos- sibly larger specimens would show a coarser ornament). They differ from C. hohnesi Bisat (1932, p. 31, pi. 1, fig. 6) in the absence of a rim around the edge of the umbilicus. Two features of the Slieve Anierin material have been particularly noted and despite the differences in preservation both features are revealed in an examination of the type material of C. subplicatum. The holotype, GSM 49963 (from Birstwith Beck, near Hampsthwaite, Yorks.), of about 11 mm. diameter, shows very fine striations with periodically sharper plications at the umbilical edge. These become less obvious away from the umbilicus but there is still a tendency for periodic striae on the flanks and venter to be stronger than their adjacent ones, which are frequently so faint as to be 390 PALAEONTOLOGY, VOLUME 5 barely perceptible. As a result of this the stronger striae stand out and give the impression of a very widely spaced ornament (seen in 7085). The other feature, already described in 7086, may possibly be associated with slightly larger size. GSM Z1 5806, a topotype of C. subplicatum , with a diameter of about 13 mm., shows the plications at the umbilical edge, but in this case there is apparently a raising up of several striae, and this bundle fans outwards away from the umbilicus and fades over the flanks and venter back into the normal convexity. Genus cravenoceratoides Hudson 1941 Genotype: Cravenoceratoides nitidus (Phillips). Cravenoceratoides nitidus (Phillips) Plate 52, fig. 6 Goniatites nitidus Phillips 1836, pp. 235-6, pi. 20, figs. 10-12. Homoceras nitidum (Phillips); Bisat 1924, p. 106. Cravenoceras nitidum (Phillips); Bisat 1932, pp. 34-35, pi. 2, fig. 3. Cravenoceratoides nitidus (Phillips); Hudson 1946, pp. 376, 383, pi. 21, fig. 11 ; pi. 2\a, figs. 1 a-c. Description. The shape is apparently cadicone. The umbilicus is rather wide, and about a third of the diameter. The ornament consists of radial bifurcating lirae. In the external impressions these can be seen to be asymmetrical (canted). The bifurcation in the lirae at a diameter of 14 mm. is about 1 mm. from the edge of the umbilicus; at the same diameter the lirae are about two per mm. on the venter. There is no forward arching in the lirae even in the largest specimens. The tendency in this species is for the bifurcation to stay uniformly close to the umbilical edge, with little or no tendency to migrate over the flank as growth advances. Dimensions. 7094: diameter 14 mm., umbilicus 4-5 mm. (PI. 52, fig. 6). 7095: diameter 28-30 mm., umbilicus c. 9 mm. 7096: diameter c. 22 mm., umbilicus 7-5-8 mm. Locality and horizon. All the specimens so far collected come from the highest faunal band, E2b3, in Valley 3, L2 1(9)24. The fauna at this level is very rich in Ct. nititoides, E. rostratum sp. nov., Euchondria aff. E. levicula, Chaenocardiola foot 'd , Weberides cf. W. shunnerensis, &c. The specimens of Ct. nititoides are more abundant than Ct. nitidus. Discussion. This species is distinguished from Ct. nititoides by the larger umbilicus and the lack of the forward curve in the lirae, which in Ct. nitidus are radial. In all the ex- amples of Ct. nititoides examined there is a tendency for the bifurcation of the lirae to EXPLANATION OF PLATE 57 All specimens are from Slieve Anierin, Co. Leitrim, Eire. Fig. 1. Cravenoceras subplicatum Bisat. 7087, external mould showing in the later whorls striae which are more widely spaced and stronger at the umbilical edge, x4-25. Fig. 2. Cravenoceratoides edalense (Bisat). 7102, external mould showing singly bifurcating symmetrical lirae, x5. Fig. 3. Anthracoceras tenuispirale Demanet. 7129, crushed specimen showing spiral ornament, x 16. Figs. 4, 5. Cravenoceratoides nititoides (Bisat). 4, 7099, external mould showing bifurcating asym- metrical lirae tending to curve forward over flanks, and the small umbilicus, x3-3. 5, 7097, X 5. Palaeontology , Vol. 5 PLATE 57 YATES, Namurian goniatites P. J. YATES: NAMURIAN OF SLIEVE ANIERIN 391 move over the flank during ontogeny. This is hardly seen at all in Ct. nitidus where the position of the bifurcation stays close to the umbilical edge. In both species the lirae are asymmetrical (canted), in contrast to the symmetrical lirae (tented) of Ct. edalense and Ct. bisati (Hudson, 1946). Schmidt (1934, p. 449, fig. 42) figures Cravenoceras cf. C. nitidum (Phillips) from Germany, and his figure shows an umbilical diameter of about a third of the total diameter, but the bifurcations are not very clear on the drawing, which cannot be compared with the present specimens. The latter are closely comparable, however, with the lectotype of Ct. nitidus , BM C279n, which has been figured by Hud- son (1946, pi. 21 a, figs. \a-c). Cravenoceratoides nititoides (Bisat) Plate 57, figs. 4, 5 Cravenoceras nititoides Bisat 1932, p. 35, pi. 2, fig. 2. Cravenoceras nititoides Bisat; Schmidt 1934, p. 450, fig. 47. Cravenoceras nititoides Bisat; Demanet 1941, pp. 143-4, pi. 6, figs. 6-8. Cravenoceratoides nititoides (Bisat); Hudson 1941, p. 282. Cravenoceratoides nititoides (Bisat); Hudson 1946, pp. 375, 376, 383, pi. 21, fig. 8. Description. This species occurs crushed, but if undeformed it would probably be a slightly flattened cadicone. The plications bifurcate once, the bifurcation occurring a short distance over the flanks away from the edge of the umbilicus. The plications have a very slight forward swing over the flanks and are asymmetrical (canted). The umbilicus is small. Dimensions. 7097: diameter 11 mm. (PI. 57, fig. 5). 7098u: large specimen, diameter 18 mm., umbilical diameter 3 mm. 7098 b: one small specimen, diameter 1 1 mm., umbilical diameter 2 mm. 7099 (counter- part 7261): very squashed, umbilicus 3-5 mm. (PI. 57, fig. 4). 7100: diameter 24 mm., umbilicus 4 mm. Locality. All the specimens were collected from the highest faunal band on Slieve Anierin, and mainly from Valley 3, L21(9)24. The band, which is about 9 inches thick, is exposed at stream level almost at the upper end of this valley. Above the band there are about 40 feet of unfossiliferous rusty shales which are followed by about 12 feet of white, flaggy sandstones with plants. Horizon. This band, which is of E2b3 age, is rich in fossils ; Ct. nititoides is very common and occurs with E. rostratum sp. nov., Chaenocardiola footii, Euchondria aff. E. levicula, Weberides cf. W. shunnerensis, Productus hibernicus, plates and spines of Archaeocidaris urii, Stroboceras subsulcatus, Fenestella sp., &c. Discussion. In his original description Bisat distinguishes this form from Ct. nitidus by the fact that ‘ the plications are somewhat forwardly arched on the conch in adolescence, becoming radial in the adult’. Also the umbilicus is smaller in nititoides than in nitidus. The canted (asymmetrical) nature of the plications in these two species distinguishes them from sharply symmetrical (tented), plicated forms such as Ct. edalense or Ct. bisati. Ct. steUarum also has typically tented plications. The holotype of Ct. nititoides from Pace Gate Beck, near Bolton Abbey, is remarkably like the forms from Slieve Anierin. Tonks (1925, pp. 251-2) originally described the Pace Gate Beck section and the fauna, as on Slieve Anierin at this level, includes E. bisulcatum, trilobites, and a Productus. Unfortunately there are no exposures at this locality now and very little of the original material is available apart from the holotype of nititoides. 392 PALAEONTOLOGY, VOLUME 5 Cravenoceratoides edalense (Bisat) Plate 56, fig. 5; Plate 57, fig. 2 Cravenoceras edalense Bisat 1928, p. 132, pi. 6, 6a, figs. 4, 4 a. Cravenoceratoides lirifer Hudson 1946, pp. 380-5, pi. 21, figs. 1-3, 5-7. Description. This form shows a planulate stage in the very early whorls, but with ad- vancing development an increasingly globose shape is assumed. In most examples a wide and deep umbilicus reveals the early planulate whorls. The degree of involution is not very great even at the very advanced stages. There is a strong and bifurcating ornament; the lirae are sharply defined and symmetrical. Hudson (1946, p. 383) uses the expression ‘tented’ for such lirae. The early planulate whorls show much finer and closer ornamentation. The venter is broad with little or no indication of a ventral sinus in the lirae. In these specimens it is rather difficult to determine the exact position of the bifurcation of the lirae; in many the single bifurcation appears very close to the umbilical edge, but in others it appears to be nearer the edge of the broad venter. Dimensions. The rather imperfect preservation of these globose forms results in distortion of their original dimensions and accurate measurements are difficult to make. The diameters of the shells have not been measured, except in the less deformed planulate stages, which are up to 5-6 mm. approximately. Localities and horizon. All the specimens have been collected from the shales in the lower part of Valley 4, L2 1 (9)23, and from localities L21 (1 3)2, L21 ( 1 3)3, and L21(9)20. They occur in the first fossiliferous horizon above the thick grit, E2bl. They are associated with subspecies of Posidonia corrugata. Discussion. Bisat (1928) originally figured Cravenoceras edalense, and subsequently refigured it (1932, p. 33, pi. 1, figs. 4a, b). The specimens refigured in 1932 were later placed by Hudson (1946) in a new species, Cravenoceratoides bisati. Hudson also erected the new species Cravenoceratoides lirifer (1946, pp. 380-5, pi. 21, figs. 1-3, 5-7). The specimens separated by Hudson from Ct. edalense s.s. as Ct. bisati are distinguished by an irregular and repeated bifurcation of the lirae. This character is seen also in the figures given by H. Schmidt (1934, p. 448, figs. 23, 24) of Cravenoceras edalense. These forms appear to be specifically distinct from Ct. edalense s.s., in which there is only one bifurca- tion, but the writer has been unable to recognize any way of separating Ct. edalense s.s. from Ct. lirifer, and since the species predated Ct. lirifer the name of Ct. edalense seems more applicable to the abundant examples which occur on Slieve Anierin. Cravenoceratoides cf. Ct. bisati Hudson Plate 56, figs. 3, 4, 6 Cravenoceratoides bisati Hudson 1945, pp. 376-80, pi. 21, figs. 4, 10; text-fig. la. Description. These specimens are similar in general shape to Ct. edalense but are distin- guished by an irregular bifurcating ornament. In addition to the tendency for repeated bifurcation there is a tendency for the neighbouring branchlets from two bifurcating lirae to run together and continue as one lira, which may subsequently be seen to bifurcate. This is best seen in specimens 7103 (PI. 56, fig. 3) and 7105 (PL 56, fig. 6). Localities and horizon. These specimens occur at the same localities as Ct. edalense s.s. and on the same horizon, E2bl, but they are not so abundant. P. J. YATES: NAMURIAN OF SLIEVE ANIERIN 393 Superfamily dimorphocerataceae Hyatt 1884 Family dimorphoceratidae Hyatt 1884 Genus kazakhoceras Ruzhencev 1947 Kazakhoceras scaliger (Schmidt) Plate 59, fig. 4 Dimorphoceras ? scaliger Schmidt 1934, p. 458, fig. 2. Description. Compressed and involute forms with a sharp venter and minute umbilicus. The most obvious feature is the lattice or reticulate pattern which covers the surface and which is unmistakable even in very small fragments of the shell. This lattice pattern bears no relationship to the growth-lines, which can frequently be seen with it. The growth-lines are suggestive of a member of the Dimorphoceratidae; the strong umbilical bow is well seen in 7108 with lattice ornament also. Dimensions. 7109 (counterpart 7249): diameter 21 mm. 7112: radius 11 mm. (PI. 59, fig. 4). 7110: diameter 14 mm. 7111 (counterpart 7246): radius 30 mm. Localities and horizons. These specimens have been collected from two levels on Slieve Anierin. At the lower level seen at L21(l 3)7, and at L21(5)4 and 5, they are associated with Cravenoceras aff. C. malhamense, Caneyella membranacea, and Chaenocardiola foot'd in EjC. At the higher level seen at L21(5)ll and at L21(13)4 the fauna is a larger one and includes Cravenoceras cf. C. gairense, E. bisulcatum erinense subsp. nov., E. bisulcatum ferrimontanum subsp. nov., Posidonia corrugata and subspecies, Chaenocardiola foot'd , and Dunbarella elegans. The species is more abundant at this higher level, which is considered to be in high E2a. Discussion. In his original description of this form H. Schmidt (1934, p. 458) doubts whether the lattice pattern is true ornament, and expresses the belief that it may be the wrinkled layer. I believe the lattice pattern is ornament, but it is impossible to be definite on this issue without studying solid specimens capable of dissection. The species is found on Slieve Anierin only at the two levels indicated above, with its greatest abun- dance undoubtedly in the E2a horizon. Schmidt’s original examples were apparently from E2 beds, as are those from the lower level on Slieve Anierin. Ruzhencev (1947) erected Kazakhoceras to include forms like Neodimorpltoceras but with differences in the suture and with a sharply keeled venter. The Slieve Anierin specimens with the lattice pattern are tentatively placed here. Many specimens with this lattice ornament in the Geological Survey Museum collection have been identified as Neodimorpltoceras haw- kinsi (Moore). In particular the material from Holbeck (Stephens et al. 1953, p. 28) has been referred to this species, but on examination these specimens appear to be the same as those which I have referred to K. scaliger. Schmidt (1934, pp. 458 ; 446, fig. 2) does not comment on the suture of his species. Neither does Moore (1958, pp. 225-6) make any comment on the ornament of K. hawkinsi, nor does he include K. scaliger in the synonymy of his species. In the absence of any definite sutural proof that these two forms are conspecific, I prefer to retain the specific name scaliger for specimens showing the lattice pattern. This practice has some stratigraphical value since the specimens only occur on two horizons. Moore (1958, p. 225) records K. hawkinsi from P2 and E, horizons and says that it is impossible to distinguish between the specimens from two such widely different levels. Neodimorpltoceras cf. N. scaliger is recorded by Hudson and Cotton (1943, p. 163) at the base of E2 and in the C. malhamense E2c zone (op. cit., 394 PALAEONTOLOGY, VOLUME 5 p. 167), and these are the same two levels at which the species has been found on Slieve Anierin. Genus anthracoceras Freeh 1899 Anthracoceras tenuispirale Demanet Plate 57, fig. 3; Plate 58, fig. 4; Plate 59, fig. 1 Anthracoceras tenuispirale Demanet 1941, pp. 148-9, pi. 6, fig. 18; pi. 7, figs. 1, 2. Description. A very involute species with a small umbilicus. The shell is ornamented with delicate radiating lirae, which when first seen are evenly curved over the flanks but progressively develop a lingua on the ventro-lateral area. With high magnification it is possible to distinguish a spiral ornament on the very early part of the shell which fades as the radial ornament becomes important. The spiral ornament is seen to be dominant on specimens up to 6 mm. diameter, at which stage the radial ornament is appearing. Thereafter the radial ornament becomes increasingly important, with a high and moderately deep lingua forming by 9 mm. diameter (7127). Indications of constrictions are present in the spirally striated specimens; 7128 shows at least three such constric- tions. Dimensions. 7126: diameter 6 mm. (radials more or less smoothly curved and just appearing). 7128 (counterpart 7357): diameter 6 mm. (radials more or less smoothly curved and just appearing) (PI. 58, fig. 4). 7129: diameter 5 mm. (spirals only) (PI. 57, fig. 3). 7130: diameter 3-5 mm. (spirals only). 7131 : diameter 8 mm. (radials beginning to show the lingua). 7132: diameter 10 mm. (radials beginning to show the lingua). 7127: diameter 9 mm. (radials showing definite lingua) (PI. 59, fig. 1). Localities and horizon. Most of the specimens were collected in Valley 3, L21(9)24. The species occurs in abundance in E2b2 between the band with E. bisulcatum leitrimense subsp. nov. and the top faunal band with E. rostratum sp. nov. and Ct. nititoides. It is associated with C. holmesi, P. corrugata, Posidoniella variabilis, and P. variabilis erecta subsp. nov. Discussion. These specimens undoubtedly show the characteristics of Demanet’s species, which has so far only been described from Belgium. Demanet apparently believes that the spirals are a feature of the inside of the test and the radials the outside. He comments that in some specimens the two forms of ornament may be seen superimposed. The author’s specimens, though numerous, are inconclusive on this point. If the spirals are internal ornament then the outside of the shell would seem to have been without orna- ment until about 5-6 mm., when the first radials appear in the author’s material. Currie, with experience of better material of Anthracoceras, states (in litt.) that the spiral ornamentation she has seen in other species has been a feature of both the inside and the outside of the test. EXPLANATION OF PLATE 58 All specimens are from Slieve Anierin, Co. Leitrim, Eire. Figs. 1, 2. Euchondria aff. E. levicula Newell. 1, 7165, external mould of right valve with no radial orna- ment, X 7-25. 2, 7158, internal mould of left valve with external ornament impressed upon it, X 6. Fig. 3. Actinopteria persulcata (M‘Coy). 7223, external mould of left valve, X4. Fig. 4. Anthracoceras tenuispirale Demanet. 7128, showing spiral striae with indications adorally of the radial ornament, X 20. Fig. 5. Posidonia corrugata (Etheridge). 7144a, left valve, X 6-5. Palaeontology , Vol. 5 PLATE 58 YATES, Namurian lamellibranchs and goniatites P. J. YATES: NAMURIAN OF SLIEVE ANIERIN 395 In view of the great abundance of A. tenuispirale on Slieve Anierin at E2b levels it seems remarkable that it has not been described from beds of the same age elsewhere. The very high magnification that is needed to see these early spirals makes it very likely that such specimens have been assigned to A. paucilobum (Phillips) or A. glabrwn Bisat, which it closely resembles in other respects. GSM CS891 from the Colsterdale Marine Band (E2b) in a stream section 300 yards west of Ivin Waite, west of Pateley Bridge, Yorks., although labelled as Cravenoceras cf. holme si is seen to be A. tenuispirale when suitably magnified. Bisat has seen a photo- graph and agrees with me (in lift., 1960) that this is the case. He also comments that this raises the question of whether some other records of C. holmesi in the literature may not in fact also be A. tenuispirale. This occurrence is interesting in that it is thought to occur at a similar level to that on which the species is so abundant on Slieve Anierin. Class lamellibranchiata Blainville 1816 Family pterinopectinidae Newell 1937 Genus posidonia Bronn 1828 Posidonia corrugata (R. Etheridge jun.) Plate 58, fig. 5; Plate 60, fig. 4 Posidonomya corrugata Etheridge 1873, pp. 103-4. Posidonomya corrugata Etheridge; Etheridge 1874, pp. 304-5, pi. 13, figs. 4, 5 (non fig. 6). Posidonomya corrugata Etheridge; Hind 1901, pp. 30-31, pi. 6, figs. 1, 2, 5. Posidonomya corrugata Etheridge; Weigelt 1922, pp. 93-95, fig. 17. Posidonomya corrugata Etheridge; Schmidt 1934, p. 446, fig. 8; p. 451, fig. 52. Posidonia corrugata (Etheridge); Ramsbottom 1959, p. 406. Description. The hinge-line is short. The height and greatest antero-posterior measure- ment are approximately the same. The umbo is prominent and nearer the anterior end of the hinge from which it is separated by a narrow anterior wing, which in some speci- mens is slightly concave but in most is flattened. The anterior margin descends from the hinge-line at first vertically but soon swings forward obliquely to this short vertical piece; farther downwards the direction of the anterior margin changes from this forward swing to a steeper one and it then curves round smoothly into the ventral margin. The posterior margin is oblique, and both it and the ventral margin show a con- siderable degree of backward extension. The surface of the valve bears strong concentric corrugations as well as less prominent growth lines. Dimensions. 7144a (counterpart 7277): left valve, height 9 mm., greatest antero-posterior measure- ment 10 mm. (PI. 58, fig. 5). 71446, c (counterpart 7277): two left valves, height 8 mm., greatest anterio-posterior measurement 7 mm. 7145 (counterpart 7278): two left valves, height c. 9mm., greatest anterio-posterior measurement 13mm. (PI. 60, fig. 4). 7146: right valve, height 7-8 mm., greatest antero- posterior measurement 7-8 mm. 7147 (counterpart 7282): left valve (also deformed right valve), incomplete greatest antero-posterior measurement 8 mm. Localities and horizons. This species has been collected abundantly at numerous horizons ranging from P2 to E2. The localities on Slieve Anierin are too numerous to list separately. Specimens are parti- cularly abundant in the shales above the grit in E2, and they are frequently the only forms present. The abundance is often such that good individual specimens are very difficult to obtain. Some of the best examples were collected in E2bl shales almost immediately above the Ct. edalense beds in Valley 4, 396 PALAEONTOLOGY, VOLUME 5 L21(9)23. Locality L23(4)5 lies in the C. leion zone but the specimens are in every way like the ones from E2. Discussion. R. Etheridge jun. (1873, pp. 103^4) described this species as being very variable. In his view nearly all the adult specimens have radial ribs in addition to the concentric corrugations. The most common form of P. corrugata in Ireland is dominated by concentric corrugations. Specimens do exist with radial corrugations but these are not the most common and have been given specific rank as Posidonomya trapezoedra by Ruprecht (1937, pp. 30-31). Subspecies of this typical P. corrugata occur at certain horizons and are described below. They are always associated with P. corrugata as interpreted above. Posidonia corrugata elongata subsp. nov. Plate 60, fig. 1 Description. The specimens ascribed to this subspecies resemble P. corrugata in the possession of a narrow anterior wing and a short hinge-line. The more dorsal part of the anterior margin also resembles P. corrugata in that it descends vertically for a short distance and then swings forward. Thereafter, however, the anterior margin differs in following a backward course in its passage into the ventral margin and in being approxi- mately parallel to the oblique posterior margin. The corrugations of the valves are in every way similar to those in P. corrugata. Ho/otype. 7148a (counterpart 7216a): probably incomplete, height 10 mm., antero-posterior measure- ment 6 mm. (PI. 60, fig. 1). Paratype. 7220: height c. 12 mm., antero-posterior dimension c. 8 mm. Type locality and horizon. This subspecies is most common in E2 but similar forms have been observed in lower beds. Some of the best examples were collected from the high E,a horizon exposed at L2 1(1 3)4, the type locality, and at L21 (5) 1 1, and also from the E2b2 beds with E. bisulcatum leitrimense subsp. nov. in Valley 4, L21(9)23. Discussion. Specimens of this subspecies differ from the typical P. corrugata in being longer and narrower in shape. This difference in aspect is produced by the more back- ward passage of the ventral portion of the anterior margin, and also the steeper posterior margin. In some respects this subspecies might be confused with the more oblique speci- mens of Canevel/a membranacea but in the latter the umbo is not so close to the anterior margin as in elongata , where the anterior ear is extremely narrow as also in the typical P. corrugata. Radial ribbing is usual in C. membranacea whereas it has not been clearly observed in elongata; if present in the latter it is faintly seen only on the more ventral part of the shell. The anterior margin in C. membranacea descends more or less vertically for some distance before curving round into the posteriorly inclined part of the margin, EXPLANATION OF PLATE 59 All specimens are from Slieve Anierin, Co. Leitrim, Eire. Fig. 1. Anthracoceras tenuispirale Demanet. 7127, showing spiral ornament in the early whorls, and radial ornament in the adult whorl, x 20. Figs. 2, 3. Obliquipecten costatus sp. nov. 2, 7217, paratype, left valve, showing radial ornament, X 5-3. 3, 7219, holotype, right valve, X 2. Fig. 4. Kazakhoceras scaliger (Schmidt). 7112, showing brickwork-like pattern, x7. Palaeontology, Vol. 5 PLATE 59 YATES, Namurian lamellibranchs and goniatites P. J. YATES: NAMURIAN OF SLIEVE ANIERIN 397 while in elongata it descends in an anterior direction obliquely to the hinge-line before curving back. Posidonia corrugata gigantea subsp. nov. Plate 60, fig. 2 Description. This subspecies is larger and more coarsely and irregularly corrugated than P. corrugata or P. corrugata elongata. Like the latter the more ventral portion of the anterior margin descends obliquely backwards but in this subspecies it is less oblique. There is considerable backward extension of the posterior and ventral margin. The posterior margin is less steep than in elongata. The height and antero-posterior measure- ment in this subspecies are approximately the same as in P. corrugata. The concentric corrugations are somewhat coarser and more irregular than in the other forms. Holotype. 7149: height 22 mm., antero-posterior measurement c. 20 mm. (PI. 60, fig. 2). Paratype. 7150 (counterpart 7353): height 20 mm., antero-posterior measurement c. 16 mm. Type locality and horizon. The best specimens have been collected in Valley 4, L21(9)23, the type locality, and Valley 3, L21(9)24. This form has so far only been seen in E2 beds. It appears to be most common in the E2b2 beds containing E. bisulcatum leitrimense subsp. nov. or just below these in E2bl. It is also present in the slightly lower Ct. edalense beds, E2bl. Discussion. Apart from the large size and the coarse ornament this subspecies appears to combine some of the features of the normal P. corrugata and of P. corrugata elongata. In the posterior margin, which is less steeply inclined than in elongata , it resembles P. corrugata. The anterior margin resembles that of elongata though it is less oblique and steeper, and only slightly backwardly inclined. As a result of its large size this sub- species is particularly vulnerable to fracture and complete specimens are rare. Genus caneyella Girty 1909 Caneyella membranacea ( M‘ Coy) Plate 60, fig. 3 Posidonomya membranacea M‘Coy 1844, p. 78, pi. 13, fig. 14. Posidonomya membranacea M‘Coy; Hind 1901, pp. 33-34, pi. 5, figs. 18-23. Posidonomya membranacea M‘Coy; Schmidt 1934, p. 446, fig. 10; (non) p. 448, fig. 28. Posidonomya (Posidonia) membranacea M‘Coy; Demanet 1941, pp. 80-81. Posidonia membranacea (M‘Coy); Smyth 1950, p. 317, pi. 17, fig. 6. Caneyella membranacea (M‘Coy); Ramsbottom 1959, p. 406, pi. 71, fig. 14. Description. The hinge-line is of moderate length, with the umbo about midway along or slightly anterior. The posterior margin is very oblique to the hinge-line and passes ventrally and backwards in an almost straight line. The anterior margin at first descends approximately vertically and then curves round to pass obliquely backwards in a path approximately parallel with the posterior margin. The surface of the valve is ornamented with concentric folds and with finer growth-lines. There is also a radial ornament of obscure radial folds, of varying strength, which pass from the umbo across the valve 398 PALAEONTOLOGY, VOLUME 5 and terminate on the ventral margin; they are most obvious over the central area of the valve. Dimensions Length — greatest distance measured parallel with the hinge-line 7154 (counterpart 7247) c. 17 mm. 7051 (counterpart 7266) c. 22 mm. (PL 60, fig. 3) Localities and horizons. These are given in the description of C. membranacea horizontalis subsp. nov. below, and the two forms are considered together in the discussion of that subspecies. Caneyella membranacea horizontalis subsp. nov. Plate 61, fig. 5 Description. In this subspecies the posterior margin is not so obviously oblique to the hinge-line, instead the two lie in practically a straight line. The growth lines, however, terminate on the anterior part of this long straight apparently dorsal margin, and the actual length of hinge-line is about the same as in C. membranacea. After the initial vertical descent the anterior margin curves round to describe a course approximately parallel with the straight dorsal edge. The ornament in this subspecies is the same as in C. membranacea except that the radial folds tend to be stronger. Dimensions Length — greatest distance measured Greatest measurement from the umbo to parallel with the hinge-line a point opposite on the ventral Ttiargin {measured parallel with the posterior margin ) 7157, holotype, (PI. 61, fig. 5) 25 mm. 22 mm. 7156 36 mm. 32 mm. Type locality and horizons. L21 (14)9, the type locality, and L23(4)19 are both considered to be high P2; at the latter, 20 feet above the base of the section, C. membranacea and C. membranacea horizontalis are associated with Goniatites granosus, Dunbarella elegans, and Sudeticeras crenistriatum. Some of the best examples on Slieve Anierin have been collected from localities L2 1(5)5 and L21(13)7, which are believed to be at about the same horizon, i.e. E^; at both these localities C. membranacea and C. membranacea horizontalis have been collected with Cravenoceras aff. C. malhamense, Kazak- hoceras scaliger, and, about 20 feet above, E. pseudobilingue s.s. Discussion. C. membranacea is a very variable species, but it is possible to separate two extreme forms according to the angle made by the posterior margin with the hinge- line. The forms figured by Hind and the original type from the Skerries, Co. Dublin Greatest distance from the umbo to a point opposite on the ventral margin {measured parallel with the posterior margin ). c. 31 mm. c. 38 mm. EXPLANATION OF PLATE 60 All specimens are from Slieve Anierin, Co. Leitrim, Eire. Fig. 1. Posidonia corrugata elongata subsp. nov. 7148a, holotype, right valve showing dorso-ventrally elongated form, X 7. Fig. 2. Posidonia corrugata gigantea subsp. nov. 7149, holotype, left valve, X2-8. Fig. 3. Caneyella membranacea (M‘Coy). 7155, showing posterior margin oblique to hinge-line, x3. Fig. 4. Posidonia corrugata (Etheridge). 7145, two left valves, X4. Fig. 5. Posidoniella variabilis Hind. 7173a, b, c, internal moulds, x4. Palaeontology, Vol. 5 PLATE 60 YATES, Namurian lamellibranchs P. J. YATES: NAMURIAN OF SLIEVE ANIERIN 399 (refigured by Hind 1901, pi. 5, fig. 18), are of the more oblique form considered as mem- branacea s.s. The specimens illustrated by Demanet (1938, pi. 10, figs. 5, 10, 11) are nearer to horizontal is ; so also is the specimen figured by Ramsbottom (1959, pi. 71, fig. 14). On Slieve Anierin the two forms usually occur together and so far have not been found in E2. All Demanet’s records are from Ex (1941, p. 81). Schmidt (1934, p. 448, fig. 28) figures the species in beds with Ct. edalense; the very narrow anterior wing suggests that this may be Posidonia corrugata e/ongata or P. corrugata gigantea, both of which occur near this level on Slieve Anierin. Smyth (1950, p. 317) reports the species in E2, but here again I believe the specimen may be more correctly regarded as a subspecies of P. corrugata. Ramsbottom (1959, p. 406) placed the species in the genus Caneyella, which he defined as including costate and non-costate species with a relatively long hinge-line, with the umbo usually towards the anterior end. It is believed that liorizon- talis is rather more abundant in the P2 horizon than in the EiC band, where membranacea s.s. is dominant. Family euchondriidae Newell 1937 Genus euchondria Meek 1874 Euchondria aff. E. levicida Newell Plate 58, figs. 1, 2 Euchondria levicida Newell 1937, p. 107, pi. 1, figs. 6, 7; pi. 19, figs. 5, 10, 11, 18. Description. Left valve. The hinge length is about half or slightly less than half of the greatest antero-posterior measurement. The umbo is slightly anterior of the mid point of the hinge-line. The shell has a postero-ventral extension. The anterior wing is small and defined from the body of the valve by a strong downfold which passes from the umbo to the anterior margin. The posterior wing is larger than the anterior but has no distinct fold marking it off externally. The anterior margin of the anterior wing is very gently curved, the posterior margin has a deep embayment below the hinge-line which swings outwards in to the postero-ventral extension. The surface of the valve is orna- mented with radiating costae. These are regularly spaced at about 4-5/ mm. They are crossed by concentric fila in which the spacing is a little more variable, from 5-7/ mm. The intersection of the two results in a cross-hatched pattern of ornamentation on the left valve. The fila continue on to the ears and there are also three to four costae on the anterior ear. The posterior ear has about five costae. It is not always easy to determine these numbers with absolute certainty as the costae do not appear to be as strong on the ears as on the body of the valve but they are definitely present in small numbers. Along the hinge margin specimen 7158 (PI. 58, fig. 2) shows a line of denticles, which may represent the position of a row of ligamental pits. Right valve. This valve lacks the postero-ventral extension. There is less discrepancy between the greatest antero-posterior measurement and the hinge length; with increase in size the discrepancy increases slightly. The anterior wing is defined by a deep furrow from the umbo to the anterior margin. This wing, although small, is very convex. The posterior wing is not defined by a furrow but is clearly distinguished by the sharp descent in the umbonal region from the convexity of the valve to the flat wing. There are no radiating costae on this valve. The fila are very clearly seen in external impressions, the 400 PALAEONTOLOGY, VOLUME 5 spacing being about 8/ mm. Although costae are absent from the valve they are present on the ears. The anterior ear has three or four costae and the posterior four to five costae. Dimensions Dorso-ventrally Antero-posteriorlv 7160, left valve 10 mm. c. 12-13 mm. 7161a, large left valve c. 13 mm. c. 15 mm. b, small left valve c. 10 mm. c. 12 mm. c. broken right valve 10 mm. 7162, incomplete left valve c. 14 mm. 7163a, right valve 15 mm. 15 mm. b, left valve 5 mm. 5 mm. c, on lower side, right valve 9 mm. 9 mm. 7164, incomplete right valve 10 mm. 7165, right valve (PI. 58, fig. 1) 8-5 mm. 9 mm. 7158, left valve (PI. 58, fig. 2) 13 mm. 15 mm. 7159a, left valve 16 mm. 18 mm. Localities and horizon. This species has only been found in the topmost faunal band on Slieve Anierin, E2b3, associated with Ct. nititoides and E. rostratum sp. nov. Numerous specimens were collected in Valley 3, L21(9)24. Discussion. The genus Euchondria (Meek 1874, pp. 488-9), as understood by Newell (1937, pp. 102-5), is typified externally by the costae and fila on the left valve, which by their intersection produce a distinctive cross-hatched ornament, and the absence of costae in the right valve, which is smooth, possessing only obscure concentric fila. The ligament area has a series of ligamental pits both before and behind the median resilifer. These two features, namely discrepant ornament on the two valves and the multiple resilifers, are taken to be the chief characters of the genus. Newell (1937, p. 102) has erected a family for these forms, in which he also places Crenipecten. He describes several species of Euchondria, of which E. levicula Newell ( 1937, p. 107, pi. 19, figs. 5, 10, 11, 18) looks very like the specimens from Slieve Anierin. The latter seem slightly different in the distinctness of the fila in the right valve and the very deep anterior auricular sulcus in this valve, but the left valve seems indistinguishable from E. levicula. Newell (in litt.) agrees with the differences just mentioned but believes that the Irish specimens should be regarded as very closely related to E. levicula. They are therefore identified as Euchondria aff. E. levicula. There appear to be no previous records of this genus in the Carboniferous rocks of either England or Ireland. The holotype and topoparatypes come from the Hushpuckney black and grey shales, Swope formation (Missouri subseries), at Devil’s Backbone, near Winterset, Iowa. Apart from the fact that this is the first record of this species outside America it is interesting also EXPLANATION OF PLATE 61 All specimens are from Slieve Anierin, Co. Leitrim, Eire. Figs. 1, 2. Chaenocardiola bisati sp. nov. 1, 7184, holotype, external mould showing low number of relatively sharp ribs separated by wide flat interspaces, x 4-5. 2, 7185, paratype, internal mould, X 5. Fig. 3. Chaenocardiola cf. C. haliotoidea (Roemer). 7183a, b, two internal moulds, X3-5. Fig. 4. Posidoniella variabilis erecta subsp. nov. 7 1 29 b, holotype ; 7 1 29c, d, paratypes, an internal mould and two external moulds respectively, showing the near vertical anterior margin, X 6. Fig. 5. Caneyella membranacea liorizontalis subsp. nov. 7157, holotype, external mould of right valve showing hinge-line and posterior margin in more or less continuous line, X 5. Palaeontology , Vol. 5 PLATE 61 5x5 YATES, Namurian lamellibranchs P. J. YATES: NAMURIAN OF SLIEVE ANIERIN 401 that it occurs in a rather different lithology from the American specimens. These (Newell, in lift.) are almost invariably found in dark to black shales, associated with pyrite, and he believes they were adapted to a low pH and strongly reducing conditions. The Slieve Anierin specimens occur in a decalcified calcareous shale with a fauna in- cluding other lamellibranchs, goniatites, a productid, crinoidal debris, trilobite remains, and occasional echinoid spines and plates. The genus does not occur beneath this band in shales of lithology similar to Newell’s description. Newell states (in litt.) that the denticles along the hinge margin in the Slieve Anierin forms (see particularly the left valve 7158 (PI. 58, fig. 2) and less obviously the right valve 7163c) tend to confirm an idea that he has had for several years that these are not ligament grooves but rather hinge denticles which are found in the juvenile stages of many modern scallops. External impressions of this species provide the clearest details of the external orna- ment but inevitably show nothing of the ligamental area. Natural moulds of the interior, with details of the external ornament impressed upon them, have frequently been preserved and these are less sharp in the details of the ornament. In 7158, a left valve, an internal mould of the ligamental area is seen along the dorsal margin of an internal mould with external ornament impressed upon it; this opinion is confirmed also by Newell. Specimen 7165 (PI. 58, fig. 1) is the impression of a right valve in which there seems to have been breakage of the valve during the life of the shell and a subsequent repair of the damage after which the growth-lines return to the normal pattern. Specimen 7166 shows the moulds of a right and a left valve closely associated, and once more internal moulds have the external ornament impressed upon them. Family aviculopectinidae Etheridge jun., emend. Newell 1937 Genus obliquipecten Hind 1903 Obliquipecten costatus sp. nov. Plate 59, figs. 2, 3 ; Plate 62, fig. 5 Description. Right valve. The hinge-line is short. The posterior margin makes an obtuse angle with the hinge-line and is gently curved and smoothly continuous with the ventral margin. The anterior margin is concave below the anterior ear but soon becomes very convex forwards. The anterior ear is very distinct in this valve and is extended above the hinge-line (this feature is well seen in 7167). There are apparently two broad undula- tions of the surface of the ear. The posterior ear is very small indeed. The extension for- ward of the valve becomes more apparent with the increase in size of the specimen; it is very marked in the holotype but less apparent in some of the smaller paratypes. Growth-lines are seen on all the specimens and are particularly sharp on the ears. There is also a distinct radial ribbing of the surface. On some of the larger right valves (notably the holotype) the ribbing is stronger on the anterior part of the shell and rather muted over the rest of the surface. In the more dorsal part of the shell the convexity of the valve decreases very sharply posteriorly but ventrally there is a much more gradual change. Left valve. In this valve the anterior ear is defined by the broad umbonal fold. The ant- erior margin of the ear is apparently smoothly continuous with the anterior margin of 402 PALAEONTOLOGY, VOLUME 5 the valve. The posterior wing is again very small. The growth-lines and radial ribbing are as in the right valve, except that in the largest specimens of the left valve seen the ribs are still apparently strong all over the surface with no particular attenuation in the ant- erior region. Holotype. 7219 (counterpart 7265) : right valve, dorso-ventrally 40 mm. (incomplete), antero-posteriorly 45 mm. (PI. 59, fig. 3). Paratypes. 7169: right and left valve, dorso-ventrally 21-22 mm., antero- posteriorly 18 mm. (PI. 62, fig. 5). 7217: left valve, dorso-ventrally 14 mm., antero-posteriorly 12 mm. (PI. 59, fig. 2). 7167 (counterpart 7168a): right valve, incomplete. 71686: left valve, other side of slab bearing counterpart of 7167, dorso-ventrally 30 mm., antero-posteriorly 28 mm. Type locality and horizon. L20(8)l; also L23(4)8. O. costatus appears to be particularly abundant in E^, where it has been found with Cravenoceras leion and Eumorphoceras cf. E. sp. form A Moore; the latter occurs at the type locality L20(8)l. The species occurs, however, at other horizons in E beds but never so abundantly. Discussion. Obliquipecten is characterized, in Newell’s opinion (1937), by ‘the remarkable extent to which the opisthocline obliquity has been carried and the nearly complete loss of the posterior auricle'. There can be no doubt that the Slieve Anierin specimens are members of this genus but they are specifically distinct from the only described species O. laevis Hind, which is described by that author (1903) as being smooth apart from the growth-lines. Newell describes the species as ‘nearly smooth save for a few fine radiat- ing costae on the anterior part of each valve and a few coarse fila on the anterior auricle of the right valve’. The Slieve Anierin specimens are considered to be specifically distinct by reason of their ribbed character. Demanet (1941, pp. 84-86) identified speci- mens in the Ex deposits of Belgium as Obliquipecten aff. O. laevis Hind but described these forms as smooth apart from concentric growth-lines. Family myalinidae Freeh Genus posidoniella de Koninck 1885 Posidoniella variabilis Hind Plate 60, fig. 5 Posidoniella variabilis (Brown MS.) Hind 1897, pp. 100-1, pi. 7, figs. 7-9. Posidoniella variabilis Hind; Ramsbottom 1959, p. 405, pi. 71, fig. 10. Description. Convex forms in which the umbo is pointed and terminal. The usual aspect is rather mytiloid. Internal moulds are frequent and are either smooth or bear somewhat irregular concentric corrugations, which appear to be more frequent nearer the ventral edge of the valves and absent or poorly seen in the more dorsal part of the valve under the umbo. The hinge-line is short and the anterior margin descends obliquely backwards making an acute angle with the hinge-line. The posterior margin is approximately parallel with the anterior, but rather more curved than the anterior. External impressions of the shell show fine concentric growth-lines and a few obscure corrugations. Dimensions. 7172: dorso-ventrally 9-5 mm., antero-posteriorly 6 mm. 7173a, b, c: largest specimen, dorso-ventrally 8 mm., antero-posteriorly 6-5 mm. (PI. 60, fig. 5). Localities and horizon. Specimens have been collected abundantly on Slieve Anierin at many levels in E2 shales above the grit from the level of the Cravenoceras subplicatum fauna, E2bl, upwards. P. J. YATES: NAMURIAN OF SLIEVE ANIERIN 403 Discussion. The author’s specimens agree closely with the species P. variabilis. Rams- bottom (1959, p. 405) has selected a lectotype from Hind’s original specimens and figured it (op. cit., pi. 71, fig. 10). He believes that of the several Millstone Grit species referred to Posidoniella, only P. variabilis rightly belongs to that genus. However, although many of my forms agree closely with P. variabilis there are others in which the mytiloid aspect is not present and a squarer form has been assumed. This change in shape is reflected in the nearly vertical downward descent of the anterior margin, in contrast to the oblique backward passage of the margin in undoubted P. variabilis. The Slieve Anierin form resembles P. laevis (Brown) (Hind 1897, pi. 6, figs. 12-14, 24), but in Ramsbottom’s opinion (/'// lift.) Brown’s original specimen had an anterior wing and therefore cannot belong to Posidoniella. However, in E2 shales on Slieve Anierin forms with a vertical anterior margin undoubtedly exist. From a study of many speci- mens it seems likely that in fact P. variabilis and the squarer form represent two ex- tremes of variation, since many specimens are difficult to assign to either end of the series. It seems desirable to name this squarer form, since the two end-forms of the series are so distinct, and this can most appropriately be done by designating it as a subspecies of P. variabilis. The name P. variabilis erect a subsp. nov. (PI. 61, fig. 4) is proposed for those forms in which the anterior margin descends vertically; holotype, 7129/?, para- types, 7129c, d. Demanet (1941, pp. 76-77, pi. 2, fig. 3) records P. variabilis within the Dimorphoceras cf. D. looneyi horizon, which corresponds with one of the periods of dominance of P. variabilis on Slieve Anierin. However, Demanet considers that the oblique anterior margin is a constant feature. H. Schmidt (1934, p. 44, fig. 45) also records this species in beds with D. looneyi. Family pteriidae Meek 1864 Genus actinopteria Hall 1884 Actinopteria per sulcata (M‘Coy) Plate 58, fig. 3 Pteronites persulcatus M‘Coy 1851, p. 170. Actinopteria persulcata (M‘Coy); Hind 1901, pp. 23-25, pi. 4, fig. 14. Description. The umbo is swollen but not quite terminal on the hinge-line, there being a narrow expansion anterior to it. The anterior margin runs obliquely backwards to the curved ventral margin. The posterior margin is smoothly continuous with the ventral margin but is ultimately concave beneath the hinge-line. The posterior wing is a long isosceles triangle in shape (with its apex at the umbo and its base the concave portion of the posterior margin). It is flattened compared with the convexity of the rest of the valve. The surface of the valve and the wing show concentric lines of growth which are quite widely spaced and reflect clearly the concavity of the posterior margin ventral to the hinge-line. There are also radial corrugations of the surface of the valve which seem to be absent on the wing in all the specimens seen. They are strongest on the middle of the valve and show a slight offset of their courses at the growth-lines. There is a long posterior extension of the hinge-line area, that of each valve being concave towards its fellow of the opposite valve. They are all unfortunately broken in this material and it is therefore impossible to tell how far this extension reached beyond the body of the valve. C 674 d d 404 PALAEONTOLOGY, VOLUME 5 Externally this extension first appears faintly as a convex ridge just below the dorsal edge of the valve at about 5 mm. behind the umbo, but is a distinctly rounded ridge just below the dorsal margin at 7 mm. from the umbo. It then continues to the posterior margin and beyond. Dimensions. 7223 (counterpart 7250): dorso-ventrally 10 mm., antero-posteriorly 12 mm. (PI. 58, fig. 3). Locality and horizon. L21(13)7, about six specimens. The horizon is EjC. The specimens are associated with Caneyella membranacea, Kazakhoceras scaliger, Chaenocardiola foot'd , and Cravenoceras aff. C. malhamense. Discussion. This is not a common species on Slieve Anierin. I compared the form initially with Actinopteria fluctuosa (Etheridge) (Hind 1901, pp. 25-26, pi. 5, figs. 8-12). However, R. B. Wilson, who has been working on these species, informs me (in lift.) that he con- siders that A. fluctuosa should now be included in A. persulcata, and this practice is followed here. In Scotland the species is particularly abundant at the P!-P2 boundary, although starting in Zone D. It therefore has a long range, since in Ireland it occurs on a high Ei horizon. ?Family conocardiidae Neumayr Genus chaenocardiola Holzapfel 1889, emend. Beushausen 1895 Chaenocardiola Holzapfel 1889, pp. 61-62. Chaenocardiola Holzapfel; Beushausen 1895, pp. 364-5. Chaenocardiola Holzapfel emend. Beushausen 1895; Hind 1900, pp. 474-6, pi. 52, figs. 5-7. Chaenocardiola Holzapfel emend. Beushausen 1895; Demanet 1941, pp. 67-69, pi. 1, figs. 5-7. Little appears to be known about the internal structure or the true affinities of this very distinctive genus. Hind mentions a certain resemblance to Conocardium. Demanet refers it to the family Conocardiidae Neumayr. Hind further states that he believes the genus is more nearly related to the Cardiidae. It is impossible to make any comment on the affinities of the Carboniferous specimens to be described. The most obvious generic features are the very strong forward curvature of the umbones and the slightly concave area just beneath the umbo on each valve. The ribbing is strong and continues from the umbo to the ventral margin and the valves are ribbed on the inside of the shell, though this usually fades before the umbo and is strongest on the ventral margin. Hind (1900, p. 476) mentioned fine striations parallel to the upper edge and interpreted them as the site of the ligament. These fine striations parallel to the upper edge have also been seen on internal moulds in many of the Slieve Anierin specimens. Chaenocardiola footii (Baily) Plate 62, fig. 3 Lunulacardium footii Baily 1860, pp. 18-19, fig. 9. Conocardium footii (Baily); Etheridge 1888, p. 281. Chaenocardiola footii (Baily); Hind 1900, pp. 475-6, pi. 52, figs. 5-7. Chaenocardiola haliotoidea Roemer; Schmidt 1934, p. 446, fig. 7. Chaenocardiola footii (Baily); Demanet 1941, pp. 67-68, fig. 5, ?fig. 6. Description. The shape is approximately semicircular. The dorsal margin is gently convex but rather more sharply so at the anterior end where it descends to the umbo. P. J. YATES: NAMURIAN OF SLIEVE ANIERIN 405 At the posterior end the dorsal margin is truncated sharply by the posterior margin, which curves quickly round into the ventral margin. At the anterior end of the shell there is a slight concavity of the surface immediately beneath the umbones. The original form does not appear to have been very convex. The umbo appears to be incurved. Strong ribs radiate from the umbo across the body of the valve and are crossed by fine concentric lines of growth. The ribs are about twenty-five in number on most specimens but may vary up to thirty. Dimensions. 7174: largest on slab, height 6 mm., length 9-5 mm. (PI. 62, fig. 3). 7175a: height 13 mm., length 16 mm. 71756: height 13 mm., length 17 mm. 7176: height 3-5 mm., length 5 mm. lllla-d: a, height 5 mm., length 1 1 mm. ; 6, height 5 mm., length 9 mm. ; c, height 4 mm., length 9 mm. ; d, height 10 mm., length 15 mm. 71486: height 8 mm., length 12 mm. 7178: height 11 mm., length 15 mm. 7179: height 10 mm., length 16 mm. 7180: height 20 mm., length 24 mm. Localities and horizons. This species has been collected from Ej and E2 beds. It has its maximum abun- dance inE2. The high E2a beds at L21(13)4, L21(5)ll, and at L21 (5)10 are rich in examples associated with the subspecies of E. bisulcatum , and Cravenoceras cf. C. gairense, &c. It occurs in abundance in the highest faunal band on Slieve Anierin, which is considered to be in the Ct. nitidus zone, E2b3, and here the species is associated with E. rostratum sp. nov., Ct. nititoides, and Ct. cf. Ct. nitidus. The species has been collected in Ej beds from all the prominent faunal bands above the C. leion zone (at this lower level it has not been collected, but Chaenocardiola bisati sp. nov. occurs). Discussion. It is apparent from a study of many specimens of this form that the shape is rather variable, ranging from young individuals in which the height of the valve is about half the length to larger specimens in which height and length are approximately equal. (Slab 7177 has young and adult specimens.) The dimensions originally given by Baily (1860, p. 19), when converted into millimetres give a height of about 20 mm. and a length of about 28 mm. This would be considered large for most of the Slieve Anierin speci- mens, but 7180 approximates to these measurements, while a few rare incomplete individuals (which if complete would be larger still) have been found. The area beneath the umbo often appears to be broken and since it carries about five ribs results in defici- ent rib counts. Although Baily’s original figure for the ribs is twenty-five, they vary up to about thirty, but twenty-five appears to be the average. The internal moulds show a distinct ribbing around the ventral margin, becoming less strong towards the umbo. Plasticine impressions of these internal moulds show that the ribs on the inside of the shell were very broad and flat-topped at the extreme ventral edge, becoming narrower as they fade towards the umbo. At the extreme ventral edge very short furrows can sometimes be seen on the flattened summits of these internal ribs. On the original specimens these short furrows appear as short intercalated ribs between the larger ribs. In internal ribbing, at least, they resemble members of the Cardiidae, for example Prosodacna sp. (Morley Davies 1935, p. 153, fig. 201), which is a member of the Adacnidae, an aberrant Miocene offshoot of the Cardiidae. The resemblance between the superficial morphology of this form and the Carboniferous Chaenocardiola is close. More detailed knowledge of the hinge and ligament area in Chaenocardiola , however, is needed before its true affinities can be determined. This species is mentioned in several faunal lists from beds of Ex and E2 age from the north of England and most of these are included by Demanet in the synonymy of the species (1941, p. 67). Stephens et al. (1942, p. 348; also 1953, p. 94) state that E. bisulcatum and Chaenocardiola footii are the two most abundant forms in the Edge 406 PALAEONTOLOGY, VOLUME 5 Marine Band in the Rombalds Moor area in Yorkshire. This band may be on the same horizon as that seen at L21 (5) 1 1 and at L21(13)4. Hudson and Cotton (1943, p. 167) record the species at two levels within Ex which can also be broadly correlated with the Slieve Anierin horizons containing the species. In Ireland the form has been recorded in North Co. Dublin by Smyth (1950, p. 320) in E2 beds. Moseley (1954) records it in the Lancaster Fells in the Tarnbrook Wyre Marine Beds of E2a age. The species is wide- spread at this low E2 level, although it occurs both lower and higher in the succession. The first Ex fauna to be described in Ireland (Nevill 1957, pp. 297-8) does not include this species nor is it mentioned in E2 (pp. 298-300). Baily’s original specimens were from Rosscliff, Co. Clare, and he mentions material from Westown, Co. Dublin; from near Drogheda, Co. Meath; and from Cahernanalt, Kendue, Co. Roscommon. Chaenocardiola cf. C. haliotoidea (Roemer) Plate 61, fig. 3 Cardital haliotoidea Roemer 1850, p. 49, pi. 8, fig. 5. Chaenocardiola haliotoidea (Roemer); Holzapfel 1889, pp. 62-63, pi. 7, figs. 5, 6. Chaenocardiola haliotoidea (Roemer); Demanet 1941, pp. 68-69, pi. 1, fig. 7; non fig. 6. Description. The shape is long and low and not very convex. The ribs are very narrow and number about forty. Dimensions. 7183a, b: two specimens, one complete, length 10 mm., height 4 mm. (PI. 61, fig. 3). Locality and horizon. Valleys 4 and 2, L21(9)23 and 25 respectively; Ct. nititoides band, E2b3. Discussion. In his description Roemer mentions forty to forty-five ribs, but there are less than this in his figure, which has a count nearer C. footii. Demanet describes this form as differing from C. footii in its smallness and its large number of ribs. Of his two figures I would refer pi. 1, fig. 6 to C. footii, but fig. 7 appears to be specifically distinct and to resemble 7183# and b. On Slieve Anierin this form has only been found in the Ct. nitidus zone. Demanet reports it also from Ex horizons. Specimens referred to this species by H. Schmidt (1934, p. 446, fig. 7) show only twenty-one ribs and may possibly be incomplete examples of C. footii; they occur in Ex beds. Chaenocardiola sp. is re- ferred to but not figured in the nitidus zone. Hudson and Cotton (1943, p. 167) record C. footii (Baily) (or C. haliotoidea (Roemer)) in Exd and Exc. The writer is uncertain exactly what is meant by this form of identifica- tion unless they intend to suggest that the two species are probably the same. The original plate given by Roemer certainly closely resembles C. footii but the definition of forty to fifty ribs is precise in the text. The highest band on Slieve Anierin contains a few rare specimens which accord with this definition and Roemer’s specific name has therefore been retained for them. Chaenocardiola bisati sp. nov. Plate 61, fig. 2 Description. The general outline of this species is as already described for Chaenocardiola footii. All the Slieve Anierin specimens discovered so far are small, but not smaller than he smallest individuals of C. footii. The valves are more convex than C. footii in the P. J. YATES: NAMURIAN OF SLIEVE ANIERIN 407 younger stages and bear a smaller number of strong ribs, which are separated by wide flat-bottomed furrows in which, at larger dimensions, intermediate finer ribs are present. There are about fifteen to seventeen ribs. There is a small distinctly concave area be- neath the umbo. Holotype. 7184: external mould, length 8 mm., height 5 mm. (PI. 61, fig. 1). Paratype. 7185 (counter- part 7237): internal mould, length 7 mm., height 4 mm. (PI. 61, fig. 2). Type locality and horizon. L24(l)l. This form is very rare and occurs in the lowest Cravenoceras leion band, Exa, associated with C. leion. Specimens have also been collected at L23(4)19 in P2 beds, as- sociated with Goniatites granosus; they are compared with this species although they are not so well preserved as the Ex examples. Discussion. Specimens of Chaenoccirdiola footii have their normal rib quotient at sizes comparable to those so far seen in this species (cf. 7167, which is a very small C. footii), and C. bisati is therefore to be distinguished by the smaller number of ribs (c. 17) separated by wide interspaces. In the Geological Survey Museum, two slabs (GSM Ca 1938 and 1939) collected from Holden Clough, Holden, Yorks., show incomplete large specimens of this species, and are associated with Goniatites elegans Bisat and are therefore of Pxc age. They show low numbers of sharp ribs (about seven but very in- complete) separated by wide interspaces. It is considered that these specimens are more adult individuals of the C. bisati described from Slieve Anierin. The dimensions of the two valves on Ca 1939 are: height c. 16 mm., length c. 23 mm. There are indications at these dimensions that in flat-bottomed grooves seen at smaller sizes there are three finer intermediary ribs, which are persistent from the umbo to the margins of the valve. The species is named in honour of Mr. W. S. Bisat. Order ptychopariida Swinnerton 1915 Suborder illaenina Jaanusson 1959 Superfamily proetacea Salter 1864 Family phillipsiidae Oehlert 1886 Genus weberides Reed 1942 Weberides cf. W. shunnerensis (King) Plate 62, figs. 1, 2 Griffithides shunnerensis King 1914, pp. 392-4, pi. 32, figs. 1-7. Description. Headshield. The glabella is inflated anteriorly and pear-shaped. The oc- cipital ring is distinctly separated from the rest of the glabella, and bears a central tubercle, with indications of others on each side of it. A pair of glabellar furrows slope back to meet the occipital furrow and define a pair of triangular-shaped basal lobes of the glabella. No other indications of glabellar furrows have been seen in front of this pair. The fixed cheeks are narrow with a well-defined palpebral lobe. The eyes are situated very close to the sides of the glabella and are distinctly reniform. In 7190 the eye is about 2-5 mm. long and is therefore about a third of the total length of the head shield. In relation to the convexity of the glabella the free cheeks are only very slightly raised. There are well-defined genal spines. In 7190 one of the spines is about 4 mm. long but without a complete specimen it is impossible to say where this spine would end 408 PALAEONTOLOGY, VOLUME 5 in relation to the thoracic segments. Surrounding the free cheeks there is a border which is about 1 mm. wide. In 7190, an impression, this border appears as a furrow in which there are about five striations which run parallel to the outer margin. Up to eight of these striations have been seen on several free cheeks. In the original trilobite the border must have been a convex band with a variable number of fine striations running parallel to the outer margin. There is a slight band between the anterior end of the glabella and the edge of the head shield; the border is very reduced in this region, its area having been invaded by the glabella. A constantly recurring feature on the glabella in the Slieve Anierin specimens is the presence of a pair of pits in front of the eye lobes and situated in the depression which surrounds and outlines the glabella. These pores are commented on by King (1914, p. 394). Each pore is situated about a quarter of the distance between the eye lobe and the front margin of the cranidium. Thorax. Unfortunately, since there are no complete specimens in the collection, the original number and form of the thoracic segments is not known. Specimen 7191 shows some fragmentary thoracic segments. The axis in these segments appears to be about 2 mm. in width and more convex than the flanking pleurae. The pleurae are not visible. On the very small and distorted specimen 7067c the thoracic pleurae appear to have straight terminations with no indications of the development of pleural spines. Pygidium. There are several good specimens of pygidia. The length varies from about 8-10 mm. The axis of the pygidium is strongly arched above the flanking pleurae, which are only moderately convex. The pygidium is surrounded by a wide border. There are about sixteen segments in the axis and about ten in the pleural region. Each axial seg- ment has a single row of granules just in front of the posterior border. A single row of granules also occurs in a similar position on each of the pleurae. Some moulds of the pygidium show a concave area surrounding the pleurae (and not the convex border seen in other moulds) and are interpreted as moulds of the ventral surface of the pygidium showing the doublure, which has striations parallel to the margin. Dimensions. 7190: the only complete headshield, width between the two genal angles 11 mm., length 7-5 mm. (PI. 62, fig. 2). 7192 (counterpart 7283): pygidium, c. 6 mm. long (PL 62, fig. 1). 7193 : cranidium, 6-5 mm. long; length of pygidium c. 7 mm., maximum width 10 mm. Localities and horizon. Fragments of trilobites occur abundantly in the highest faunal band, E2b3, on Slieve Anierin. The most extensive collecting from this band was carried out in Valley 3, L21(9)24. The trilobite specimens are associated with Ct. nititoides, E. rostraturn sp. nov., Chaenocardiola footii, Euchondria aff. E. levicula, &c. Discussion. These specimens compare very closely, allowing for differences in preserva- tion, with Griffithides shunnerensis, described by King (1914), now known as Weberides shunnerensis (see Reed 1942, p. 653). The type specimens were collected from the Shun- EXPLANATION OF PLATE 62 All specimens are from Slieve Anierin, Co. Leitrim, Eire. Figs. 1, 2. Weberides cf. W. shunnerensis (King). 1, 7192, pygidium, x7. 2, 7190, cranidium, X6. Fig. 3. Chaenocardiola footii (Baily). 7174, external mould, x6-5. Fig. 4. Edestus ( Edestodus ) sp. GSM 86950, external mould, X 4. Fig. 5. Obliquipecten costatus sp. nov. 7169, paratype, external mould of right valve partly obscuring a right valve, probably an internal mould with external ornament partially impressed upon it, X 3-3. Palaeontology , Vol. 5 PLATE 62 5x33 YATES, Namurian fossils P. J. YATES: NAMURIAN OF SLIEVE ANIERIN 409 ner Fell Limestone, Great Shunner Fell, Wensleydale, north Yorkshire, a highly fos- siliferous rock which yields an E2 fauna. The Yorkshire specimens are therefore of the same general age as those from Slieve Anierin. Slight differences may exist in the num- ber of axial segments in the pygidium, but most of the Slieve Anierin specimens are broken at the anterior end of the pygidium and the number of segments may well be more than the figures given. There are several records of trilobites at this level in England and Ireland, but a generic name is not usually given. Scanlon (1953), Smyth (1950), and Nevill (1957) all record trilobite remains in E2 beds in Ireland. Hudson and Cotton (1943) record a trilobite in the Alport Dale boring, Derbyshire, associated with a fauna very similar to that on Slieve Anierin. Tonks (1925) lists a trilobite in the fauna from Pace Gate Beck, Yorkshire, in beds which also yielded the type of Ct. nititoides. Demanet (1941, p. 154, pi. 7, figs. 4, 6) describes and figures a trilobite from E2 near Bioul in Belgium, but it is not the same species and appears to be rather larger. Superclass pisces Class CHONDRICHTHYES Subclass ELASMOBRANCHII Order selachii Suborder hybodontoidea Family edestidae Genus edestus Leidy 1856 Edestus (Edestodus) sp. Plate 62, fig. 4 Description. The crown of this tooth is triangular, laterally compressed and symmetrical. Small subsidiary cusps occur at the base both anteriorly and posteriorly. The anterior and posterior edges of the tooth are serrated. There are eleven to twelve of these small denticulations along each margin but some may have been rubbed away near the apex. Each denticulation appears to be undivided. At the base of the tooth there are several raised ridges (seen as furrows in this impression). Dimensions. Height 16 mm., width at base 18-5 mm. (PI. 62, fig. 4). Locality and horizon. A single specimen only has been collected (GSM 86950) from the horizon of Ct. nititoides, E2b3, in Valley 3, L21(9)24. Discussion. Specimens of Edestus are extremely rare in English deposits and this is believed to be the first record from Ireland. The writer is indebted to Dr. Ramsbottom of the Geological Survey for identifying this specimen, indicating its rare nature, and also pointing out to me the paper in Russian by Obruchev (1953) on this family. The relevant generic definitions in this work (pp. 59-60) were translated with the assistance of Dr. Skiba of the Department of Geology, Imperial College. The Slieve Anierin specimen accords most nearly with the subgenus Edestodus Obruchev (type species Edestodus minor (Newberry)) in the sharply triangular outline and the small angle at the apex of the tooth which in Edestodus is 25-35°, and which in this specimen is approximately 29°. In the presence of the subsidiary cusps each side at the base the specimen shows 410 PALAEONTOLOGY, VOLUME 5 some resemblance to Edestus heinrichsii Newberry and Worthen (1870, pp. 350-3, pi. 1, figs. 1 a, b ), which is now assigned by Obruchev to the subgenus Protopirata Traut- schold (in which the apical angle varies from 70-90°). In this species the denticles are few in number and the basal ones at the anterior and posterior margins are enlarged almost to form subsidiary cusps. The type species of the subgenus Lestrodus Obruchev is L. newtoni (Woodward) and in the original description by Woodward (1916, pp. 1-6, pi. 1) was described as possessing vertical plications or flutings at the base of the crown. These are also seen on the Slieve Anierin specimen but are more regular and more marked than in the specimens of L. newtoni; in this genus the apical angle varies from 40-45°. CORRELATIONS WITH OTHER AREAS Px-Po Beds The fossils preserved in beds of P^Pa age are too poorly preserved to allow close correlation with beds of the same age elsewhere. Hudson and Cotton (1945 a, pp. 273-8), working on the Alport borehole, established a correlation with Germany. The sequence of faunas within Px was correlated with that from Edertal on the eastern side of the Rhenish Schiefergebirges (Pickel 1937) and the P2 succession was compared with that in the northern Sauerland (Ruprecht 1937). There is less similarity between the P2 faunas than those of Px but this, in the opinion of Hudson and Cotton (op. cit., p. 275), is mostly due to the poor definition of the diagnostic features of the species and the re- sulting difficulty in identification. The material of this age from Slieve Anierin adds nothing to the detailed subzoning and correlation established by Hudson and Cotton. Basal E1 to Middle E2 1. Ireland North Co. Dublin. Smyth (1950, pp. 297-304) showed that Pendleian deposits are absent in North Co. Dublin and that Arnsbergian beds succeed beds of P2 age and overlap onto the Lower Palaeozoic. This absence of Ex and overlap of E, is due to the Sudetian orogeny. As a result of faulting the succession is not so simply interpreted as the Slieve Anierin succession, nor do the described faunas appear to be so abundant. A fauna is described (op. cit., p. 298) which is in part reminiscent of the highest Ct. nititoides fauna on Slieve Anierin, a notable similarity being the occurrence in both of Produetus hibernicus and a Phillipsiid trilobite ( Weberides cf. W. shunnerensis on Slieve Anierin). Unfortunately this band was not found in direct relationship to any of the other described sections; Smyth (p. 302) believes that the Rowans Brook and Walshes- town sections cover the E. bisulcatum s.s. and Ct. nitidus zones, and that the P. hibernicus fauna is higher than any part of these two sections. On Slieve Anierin the fauna with P. hibernicus is included in the Ct. nitidus subzone. In the Rowans Brook section, which is the most complete, there are about 400 feet of beds, predominantly shale, of which about 60 feet at the base are in the Balrickard Sandstone; at other localities it is estimated that this sandstone must be considerably over 100 feet in thickness. North Co. Dublin and Slieve Anierin are alike, therefore, in the presence of a considerable thickness of arenaceous rocks within the lower part of E,. The first E. bisulcatum to be found above P. J. YATES: NAMURIAN OF SLIEVE ANIERIN 411 this grit has not been figured but has been described by Stubblefield (in Smyth 1950, pp. 318-19) as intermediate between E. bisulcatum grassingtonense and examples of E. bisulcatum from the Edge Marine Band at Cononley Beck, Yorkshire. It is probable that these forms represent a higher horizon than those on Slieve Anierin since within 20 feet they are succeeded by Ct. cf. Ct. stellarum, a species which has not been found on Slieve Anierin. No account is given of any faunas between the grit and this band with E. bisulcatum. E2 deposits from near Garristown were described by Scanlon (1953, pp. 145-57). The faunas are too poor for close comparison and there is no record of E. bisulcatum itself but of Ct. stellarum and Cravenoceras sp. Co. Meath. Nevill (1957, pp. 297-300) recorded both Pendleian and Arnsbergian stages in the Summerhill Basin, but lack of detailed information on the faunas and incomplete exposure of parts of the succession precludes any close correlation. The combined Ex- E2 stages are about 2,000 feet thick and the precise position of the boundary between the two stages has not been established. A basal Et goniatite fauna which has much in common with the fauna at L23(4)7 on Slieve Anierin is described, but the rest of the Pendleian is not exposed and the lowest exposed E2 horizon is of E2b age, consisting of beds with Ct. edalense. Two hundred feet of the succession are not exposed, and this would account for the absence of all the horizons which are present above Ct. edalense on Slieve Anierin. Ct. stellarum was collected about 300 feet above Ct. edalense. In two isolated exposures in the Summerhill Basin which have not been related to the main succession (described from a drainage dyke at Mullagh) E. bisulcatum is associated with a Cravenoceras, an Anthracoceras, and a rich brachiopod fauna including P. hibernicus, a trilobite, Dunbarella sp., Posidoniella sp., P. sulcata (Hind), a coiled nauti- loid and crinoid ossicles. Nevill believes that these beds are closely followed by Sab- denian strata and therefore higher than the succession described from the Mullagh dyke. On Slieve Anierin P. hibernicus is associated with E. rostratum sp. nov., Ct. nititoides , and Weberides cf. W. shunnerensis and is at a lower horizon than Ct. stellarum, which does not occur on Slieve Anierin. If Smyth and Nevill are correct in attributing their isolated faunas to high E2 then a somewhat similar band must also occur at the lower level within the Ct. nitidus subzone. Neither author has described or figured the E. bisulcatum which occurs at this level but both refer to Cravenoceras sp. On Slieve Anierin the associated goniatite is undoubtedly Cravenoceratoides. The Slieve Anierin fauna includes several other forms which one would have expected to see in the faunal lists of these authors if they were describing the same horizon, e.g. Chaenocardiola and Euchon- dria, both abundant in the Ct. nititoides band. Nevill (1957, p. 296) also mentions the abundance in P2 and low Ex horizons of a large compressed goniatite referred to as Anthracoceras‘1 (pi. 22, figs. 6, 7). Similar forms have been collected on Slieve Anierin at these levels and identified as Kazakhoceras sp. Both Smyth and Nevill therefore provide information on what is probably the highest subzone of the Ct. nitidus zone (i.e. the Ct. stellarum subzone), but do not shed any light on the lower parts of E2 or E1; except for the basal beds of the latter in the Summerhill Basin. A considerable sandstone episode within E2 also occurs in North Co. Dublin, as in Leitrim. The greywacke facies described by Nevill at the base of Ex has not been observed in Leitrim. 412 PALAEONTOLOGY, VOLUME 5 Cuilcagh, borders of Co. Cavan and Co. Fermanagh. Padget (1953, pp. 17-26) described the geology of Cuilcagh (2,188 feet), which is only 10 miles from Slieve Anierin and is included in the same area of Upper Carboniferous rocks. He recorded only Ex fossils (apart from the P2 and PL forms) and found no evidence of E2. The fauna from a low Ex horizon included E. stubblefieldi and C. leion; no higher goniatite-bearing beds were found in situ , but C. cf. C. malhamense was collected from some loose blocks. Padget makes no suggestion as to the age of the succeeding shales or the grit which forms the escarpment. The latter is identical with that on Slieve Anierin, which has been proved to he within E2. On Benbrack (1,648 feet), to the south of Cuilcagh, the writer has collected Eumorphoceras cf. E. bisulcatum grassingtonense (GSM 95317) and believes it occurs at the same level as at localities L21(5)8 and 9, and at L21(l 3)5 and 6. Jt is therefore probable that the same faunas exist on Cuilcagh, though possibly not so well exposed as on Slieve Anierin. Pa/aeogeography. Hodson (1959, pp. 134—50) has discussed the palaeogeography of western Europe in Homoceras times and has shown (pi. 1) an embayment of the sea into the North Atlantic Continent in the north-western area of Ireland, which includes Slieve Anierin, where the Namurian beds succeed the Visean conformably. The position of the southern margin of this embayment is based on evidence provided by the (un- published) work of Hodson and Kelk, and there is apparently overlap to the south-west so that E2 shales he on Carboniferous Limestone in the south-western part of the Slieve Carna outlier north of Balia in Co. Mayo. South of the North Atlantic Continent lay a Central Trough of sedimentation. Hodson (1954#) demonstrated the effects of the Sudetian earth-movements in north- west Co. Clare by the discovery there of Homoceras beds succeeding the Carboniferous Limestone; all the beds exposed on Slieve Anierin together with the N. nuculum beds (not present on the mountain) are absent and there is therefore a large non-sequence. The effects of the orogeny become less evident southwards across this trough and Hod- son (1959, p. 140) describes a thick Ex succession overlying the Carboniferous Limestone on the north bank of the River Shannon. Still further south the Lower Namurian beds are again overstepped, and the southern edge of the trough (against the westerly con- tinuation of St. George’s Land) is apparently near Ballagh, west of Newcastle West, Co. Limerick, where, as in Co. Clare, Homoceras is found resting on Carboniferous Lime- stone. The Sudetian earth-movements have also been detected by Smyth (1950, pp. 295- 326) in North Co. Dublin, where the whole of the Pendleian is absent. Larther south, in the Summerhill Basin, Co. Meath, Nevill (1957) found Ex and E2 beds succeeding P2, and in this area some of the higher beds of H and Rx are also preserved. The Summerhill Basin is farther away from the shoreline of the Central Trough than North Co. Dublin and the Arnsbergian deposits are correspondingly thicker. The relationship of the Sum- merhill succession to the North Co. Dublin succession is very like that of the Slieve Anierin succession to that south of the embayment at Slieve Carna. On Slieve Anierin the higher zones which are preserved in the Summerhill Basin have presumably been removed by erosion leaving only the beds of Eumorphoceras age. Hodson (1959, p. 139) postulated a marine connexion between the Central Trough and the north-western Ireland embayment on the basis of the faunal and lithological P. J. YATES: NAMURI AN OF SLIEVE ANIERIN 413 similarity of the two areas. The close correlation which it is possible to establish between the Slieve Anierin succession and those of areas in the Central Trough in Ej^ and E2 times amply testify the accuracy of this statement. 2. Southern and Mid-Pennines, England The only complete record of the Arnsbergian succession is that given by Hudson and Cotton (1943, pp. 160-72) from the Alport Dale borehole in Derbyshire. A large number of the other known occurrences of certain faunas do not allow an accurate determination of their order of superposition. The Pendleian succession is also included in the Alport borehole. Three zones were defined within the Pendleian by Hudson and Mitchell (1936, p. 26) in the Skipton Anticline in Yorkshire: EjC Subzone of Cravenoceras malhamense Ejb „ „ Eumorphoceras pseudobilingue s.s. and Cravenoceras sp. E:a ,, „ Cravenoceras leion and Eumorphoceras pseudobilingue (early form) Hudson and Cotton recognized these subzones in the Alport borehole section, but treated them as zones, and added E^d, the Eumorphoceras aff. E. pseudobilingue zone. In the Slaidburn district of Yorkshire Parkinson (1936, pp. 318-20, pi. 24) recognized: Upper Ex Lower Ex Cravenoceras malhamense Eumorphoceras pseudobilingue C „ „ B ( „ A \ Cravenoceras leion Chaenocardiola foot'd In this area the C. malhamense beds are succeeded by the Pendle Top Grit. There is obviously a close correlation between the Slieve Anierin and Pennine successions, though the grit which succeeds the C. malhamense beds in the Slaidburn area is not present until later in the succession in Co. Leitrim. (a) Cravenoceras leion zone. Apart from the plates in Nevill (1957, pi. 22, figs. 1-3) and Bisat (1950, pi. 1, figs. 1, 2) E. pseudobilingue A has never been described by Bisat although he contrasted it with E. pseudocoronula (1950, p. 19). The former is placed by Bisat (p. 24) somewhat above the base of the C. leion zone with E. pseudocoronula, C. leion, E. stubblefieldi, &c. On Slieve Anierin the maximum abundance of this species occurs with C. leion slightly above beds in which E. pseudocoronula is more abundant and it is associated with E. rota. On specimen GSM 84690 from Little Mearley Clough, E. pseudocoronula is associated with a fragment identified as E. rota. At the top of the zone or nearly so on Slieve Anierin E. medusa occurs, and slightly higher E. medusa sinuosum. Both these forms are believed to be related to the stratigraphically lower E. pseudocoronula. Specimen GSM Ca4782, previously identified as Eumorphoceras aff. E. hudsoni Gill, is thought to belong to E. medusa\ it was collected about 40 feet above the lowest C. leion beds in Bateson Wood, 550 yards north-east of Crag House, Yorkshire. Bisat, who originally identified this specimen, noting that it might be undescribed, agrees (in lift., 1960) with this identification. E. hudsoni has not been collected in this zone nor in the succeeding one; Bisat (1950, 414 PALAEONTOLOGY, VOLUME 5 p. 24) includes it within E^, although Gill (1947, p. 64) is uncertain whether the band is in E^ or Ejb. E. stubblefieldi has not been seen either, although included by Bisat at the level of E. pseudocoronula and E. pseudobilingue A. The lamellibranchs at this level seem to have been neglected. Hudson and Cotton (1943, p. 169) record Pseudamusium in the Alport borehole, and also Posidonia mem- branacea (now Caneyella membranacea ) and Posidonia cf. P. corrugata. Obliquipecten is not included though it is an abundant element in very low Et beds in Leitrim, as- sociated with C. leion, whereas Pseudamusium is more abundant at the top of the zone with E. medusa. Several specimens from the Alport borehole material are referred to in Book 30 at the Geological Survey Museum as Posidonia sp. These have been examined and found to be the same as Slieve Anierin forms referred to P. trapezoedra , which is extremely abundant towards the upper part of the zone. GSM Zh2000 is a slab showing Dimorphoceras sp. and P. trapezoedra, and was collected from a depth of 1065-6 feet (GSM, Book 30, p. 281). This is valuable confirmatory evidence of the burst in development of this species at about this level. From a depth of 1060-1 feet, which is 6 feet below the top of the zone, GSM Zhl973 has been identified as Girtyoceras sp. but may be compared with E. medusa sinuosum which occurs at the top of the zone in Leitrim. Bisat (1950, p. 14) refers to the occurrence of Eumorphoceras aff. E. hudsoni at 1064 feet in the Alport material. GSM Zhl993 collected at this depth, and similarly identified, is very like the Bateson Wood specimen GSM Ca4782 and is now believed to be E. medusa. At lower depths in the borehole (1072-3 feet) GSM Zh2026, E. pseudobilingue A, is very close to the specimens collected from locality L23(4)7 where this species and C. leion are about equally abundant. Hudson and Cotton refer to a Dimorphoceras phase in E^ and these specimens have been examined and compared with Slieve Anierin specimens referred to Kazakhoceras sp., which are abundant at about the level at which P. trapezoedra first becomes so notice- able. The Alport specimens are all poor and apart from the fact that like the Slieve Anierin examples they are all very narrow compressed forms, little more can be estab- lished. In the lower part of the succession in the Alport borehole Eumorphoceras sp. form A Moore is apparently more common than E. pseudocoronula. The former has only been imperfectly seen on Slieve Anierin at a level at which C. leion is dominant, with Ob- liquipecten costatus\ either this horizon or the level of E. pseudocoronula and E. rota could be the one with the oldest Exa fauna, though the writer believes that the latter band is lower. There is, however, close correspondence between the successions at Alport Dale and Slieve Anierin in the larger part of the zone and the lack of precise correspondence in the lower part is partly due to the poorness of the Alport borehole material. ( b ) Eumorphoceras pseudobilingue zone. Hudson and Cotton (1943, p. 168) state that Cravenoceras is not common in this zone in the Alport borehole, and on Slieve Anierin it has not been collected from beds assigned to this zone. P. trapezoedra continues from the C. leion zone and in the Alport material poor specimens referred to as Posidonia cf. P. costata are believed to be the same as such specimens as GSM Zh2000 ( P . trapezoedra ) from the lower zone, so that the species apparently continues in both areas. Eumorphoceras cf. E. angustum is a very abundant species at this level on Slieve P. J. YATES: NAMURIAN OF SLIEVE ANIERIN 415 Anierin. Though it had not been defined at the time of identification of the Alport material, it nevertheless does not seem to be present. Moore (1946, p. 439) places the species in the E. pseudobilingue zone and states (p. 440) that the two species are not necessarily on the same horizon. On Slieve Anierin this species directly underlies E. pseudobilingue s.s. and is associated with P. trapezoedra and Kazakhoeeras sp. showing a strongly beaded, sharp venter. The presence of notching on the sharp mid-venter is also believed to be present in the later stages of E. pseudobilingue s.s. which succeeds E. cf. E. angustum. Stephens et al. (1953, p. 92) further confirm the presence of P. trape- zoedra in the E. pseudobilingue zone. In the same memoir (loc. cit.) a goniatite referred to as Ewnorphoceras aff. E. pseudo- bilingue is described from Ramshaw Beck in older beds than E. pseudobilingue s.s.; it has poorly developed ribs, a more prominent sulcus, faint spiral ornament, and a beaded keel in old age. No species which exactly fits this description has been found on Slieve Anierin. The venter has not been seen to be beaded at the diameter usually found in Ewnorphoceras cf. E. angustum and the shoulder ridge is a very faintly developed fea- ture, although in some of the specimens the faint plications of the surface which replace the earlier strong ribs ridge the surface of the faint shoulder ridge where they cross it and make the latter slightly more obvious. The beaded venter has been most obviously seen in the large compressed Kazakhoeeras sp. The succeeding specimens of E. pseudobilingue s.s. accord very well with GSM 72927 from Little Mearley Clough, near Clitheroe, and is presumably the form intended by Bisat (1928, pi. 6) as E. pseudobilingue B. On Slieve Anierin a few forms succeed E. pseudobilingue B; they have been figured and described as E. pseudobilingue C. Although they have some resemblance to E. pseudobilingue s.s. they show an earlier fading of the ribs, which are less wavy than the ribs in E. pseudobilingue s.s. and with a prominent groove in the shoulder region. Parkinson (1936, pi. 24) referred to E. pseudobilingue C occurring below Cravenoceras malhamense. Bisat (in lift., 1960) agrees that a shoulder groove is a marked feature of this form. Specimens collected by Parkinson from Studforth Gill have been presented by Bisat to the Geological Survey Museum (GSM Z1 5773-6) and have been examined, but only one specimen resembles the Slieve Anierin examples. It seems likely therefore that those specimens occurring below C. malhamense should be referred to this form, but as Bisat has never defined or figured it, there is no holotype for comparison; however, Bisat (in lift., 1960) has agreed with the identification. The species E. pseudobilingue s.l., as seen on Slieve Anierin, shows a reduction in the number of ribs; in E. pseudobilingue s.s. they are fewer and with wider interspaces than in E. pseudobilingue A ; in E. pseudobilingue C the ribs fade earlier and are narrow and sharp as in the lower E. pseudobilingue s.s., but less tenuous in their passage across the flank than in that species. The shoulder ridge is lost and a groove more reminiscent of the later E. bisulcatum appears. On Slieve Anierin at this level Chaenocardiola foot'd occurs. It is noted by Parkinson (1936, pi. 24) as appearing at the level of C. malhamense but on Slieve Anierin is definitely associated with E. pseudobilingue C, together with small P. corrugata but not P. trapezoedra. (c) Cravenoceras malhamense zone. Hudson and Cotton (1953, p. 167) list C. mat- 416 PALAEONTOLOGY, VOLUME 5 Immense, Neodimorphoceras scaliger (Schmidt) and Chaenocardiola footii as the charac- teristic fossils of the C. malhamense zone in the Alport borehole, providing a striking correlation with the beds of the same age seen at localities L2 1(1 3)7 and L2 1(5)5 on Slieve Anierin. CaneyeUa membranacea is also abundant on Slieve Anierin, and is included in Hudson and Cotton’s faunal list. On Slieve Anierin this is the highest level at which C. membranacea has been collected, and at this level most of the forms are referred to C. membranacea s.s., its subspecies horizontalis being less abundant. No specimens of Eumorphoceras are known from Derbyshire or Slieve Anierin at this level, so that there is close correlation between the two areas on this point. In the Bradford and Skipton Memoir (Stephens et al. 1953, p. 92) Cravenoceras aff. C. malham- ense is reported from Howgill Beck, associated with C. membranacea and E. pseudo- bilingue; this association contrasts with their separation in Leitrim and in Alport Dale. (d) Egd zone or E2a faunas. The next fossiliferous level on Slieve Anierin is thought to correspond to the Exd zone of Hudson and Cotton (1953, pp. 166-7). The most abundant species at this level is C. cowlingense. A comparison of these specimens with those collected from the Mirk Fell Beds of Tan Hill in Yorkshire by Hudson (1941, pp. 279-83) leads to the conclusion that they belong to the same species. The Mirk Fell beds are referred to E2 by Hudson, and Anthraeoceras aff. A. paucilobum occurs with C. cowlingense. Stubblefield (Hudson and Stubblefield 1945, p. 136) also believes that the horizon of C. cowlingense is low E2 not Exd. On Slieve Anierin C. cowlingense is associated with a rather poor fauna, but including a few specimens of E. bisulcatum grassingtonense , P. corrugata, P. lamellosa, and Chaeno- cardiola footii. The Tan Hill fauna is rather different from the goniatite-lamellibranch fauna on Slieve Anierin since it includes nuculids and small gastropods but no examples of Posidonia or Posidoniella ; there is also an apparent absence of fossil wood debris, which is quite common at the level of C. cowlingense on Slieve Anierin. The lucky preservation of a suture in one of the Slieve Anierin specimens of C. cowlingense confirms the accuracy of the identification. Hudson (1941, p. 281) has figured the suture-line of GSM 62813 from Mirk Fell Beck and of GSM 62824, a meta- type of the species from an erratic in Keighley Churchyard, and a comparison of these with the Slieve Anierin specimen leaves no doubt of their being the same form. A com- parison of specimens GSM CS571-4, 582, and 584 collected from the Cockhill Marine Band in Gillfields Adit, also established this identification; a very large specimen, GSM Zh2908, is from the same horizon at the Cockhill Adit. These examples of C. cowlingense are particularly interesting since the Cockhill Limestone is the horizon from which Dunham and Stubblefield (1944, pp. 237-9) described E. bisulcatum grassingtonense and which they place in E2. Cravenoceras is dominant in the Cockhill Limestone and since there is only one specimen of grassing- tonense at the Geological Survey Museum it would appear that specimens of Eumorpho- ceras are as rare as they are at this level on Slieve Anierin. Dunham and Stubblefield suggest a correlation of this level with the Edge Marine Band, described by Stephens et al. (1942, p. 348) but in a footnote (p. 238) they also consider that it may be slightly later than this band. The Slieve Anierin succession shows two decided levels within beds referred to E2a, the lower dominated by C. cowlingense and with rare examples of rather variable P. J. YATES: NAMURIAN OF SLIEVE ANIERIN 417 Eumorphoceras, some of which are definitely E. bisulcatum, and which have been com- pared with grassingtonense ; and the upper level with E. bisulcatum erinense subsp. nov. and E. bisulcatum ferrimontanum subsp. nov. dominant, with Chaenocardiola footii the most abundant lamellibranch, and with no C. cowlingense. The upper level is believed to be that of the Edge Marine Band. The Eid fauna described by Hudson and Cotton in the Alport borehole is correlated with the lower E,a faunal band on Slieve Anierin. The Eumorphoceras specimens from Slieve Anierin {this paper) Greenhow Mining Area {Dunham and Stubblefield 1944) Bradford and Skipton Area {Stephens et al. 1953) Lancaster Fells {Moseley 1954) Alport Dale {Hudson and Cotton 1943) Grit Red Scar Marchup Grit Roeburndale Grit Grit Group Barren shales Shales and Shales and Brennand Grits Sandstone Sandstones, Bands &c. High E2a E. bisulcatum ferrimontanum not Edge Chaenocardiola footii known Marine in Band E,a E. bisulcatum erinense the Weston Brennand Band 399-408 ft. Chaenocardiola footii area Marine Band Barren shales Shales and Skipton Weston Sandstone Moor Grit Bands Grits Lowest Em Dominant C. cowlingense Cockhill Tarnbrook Ejd and rare E. bisulcatum Limestone Valley Band 453-63 ft. grassingtonense table 3. Suggested correlations between the fossiliferous bands in E2a on Slieve Anierin and some bands of similar age in northern England. this level in the borehole section are poor and have been variously referred to as Eumorphoceras cf. E. pseudobilingue and E. aff. E. pseudobilingue, but Hudson and Cotton (1943, p. 167) state that many of the latter are indistinguishable from E. bisul- catum. The writer compares GSM Zhll64 with forms collected from the lowest E2a faunal band on Slieve Anierin. The evidence suggests that the forms of Eumorphoceras at this level are rather variable, and Hudson and Cotton’s view that the fauna has more in common with the Pendleian than the Arnsbergian may be justifiable in some respects, but the writer prefers to assign these beds to E2 because of the presence of E. bisulcatum. In the Lancaster Fells, Moseley (1954, pp. 428-30) suggests that beds with C. cowling- ense and E. bisulcatum should be correlated with the Edge Marine Band and included in the Arnsbergian, and not the Pendleian as in Hudson (1945, p. 3) and Hudson and Cotton (1943, p. 166). It is now suggested that the band with C. cowlingense and E. bisulcatum grassingtonense should be correlated with the Cockhill Limestone and Hudson’s Exd level at Alport Dale. The writer correlates the Edge Marine Band of 418 PALAEONTOLOGY, VOLUME 5 Rombalds Moor with the higher band in E2a on Slieve Anierin in which E. bisulcatum is the most abundant form; the whole fauna is a richer one than at the lower level in E2a. Moseley (1954, pp. 429-30) states that the Tarnbrook Wyre Marine Beds (E2a) are made up of two horizons, but as they are exposed in different localities he is uncertain of their relative positions ; he believes that the Brennand outcrops in which E. bisulcatum is the dominant form is the lower band. The other fauna in the upper Tarnbrook Valley contains an association of C. cowlingense and E. bisulcatum. The Slieve Anierin suc- cession shows that the Tarnbrook Valley material is lower and the Brennand outcrops probably equivalent to the second E2a level on Slieve Anierin. Specimens of E. bisulcatum from some Brennand material kindly provided by Bisat appear to be close to those from the second faunal band in E2a which are referred to as E. bisulcatum erinense subsp. nov. Stephens et al. (1942, p. 348) describe the Edge Marine Band, and state that E. bisulcatum and Chaenocardiola footii are the most abundant forms. This is reminiscent of the second faunal band in E2a on Slieve Anierin and contrasts strongly with the fauna of the lower E2a band. The specimens of E. bisulcatum at this level on Slieve Anierin are believed to be very close indeed to E. bisulcatum s.s. but there are two subspecies present within this band, the lower being erinense and the higher ferrimontanum. Good speci- mens from the Edge Marine Band appear to be very rare and Bisat (in lift., 1960) does not recall seeing any good specimens. The material mentioned in the Bradford and Skipton memoir (Stephens et al. 1953, p. 25) has been examined, but is extremely poor and inconclusive. Dunham and Stubblefield (1944, p. 260) refer to specimen GSM GM3675 (see pi. 3, fig. 3) and suggest a resemblance to grassingtonense. The writer suggests rather a resemblance to E. bisulcatum ferrimontanum subsp. nov. from localities L2 1(5) 1 1 and L21(13)4. GSM GM3675 was collected from Cononley Beck and is about the best specimen in the material mentioned by Stephens et al. (1953, p. 25). There is an additional line of evidence by means of which the second faunal band in E2a on Slieve Anierin can be correlated with beds elsewhere, since in Ireland two very easily deter- mined goniatites, viz. Kazakhoceras scaliger and Cravenoceras cf. C. gairense, are associated rather less abundantly with E. bisulcatum. K. scaliger is an abundant member of the fauna attributed by Hudson and Cotton (1943, pp. 162-3) to E2a. The fauna from 399-408 feet in the Alport borehole has been examined and although the specimens of E. bisulcatum are not easily compared, since many of them seem to be gerontic individ- uals, the examples of K. scaliger are easily determined even from very small fragments. Crinoid ossicles also appear to be common at this level, as on Slieve Anierin in the second E2a faunal band. It is therefore suggested that the second faunal band on Slieve Anierin should be correlated with this level in Alport Dale. A fauna is described in the Bradford and Skipton memoir (Stephens et al. 1953, p. 28) from the left bank of Holbeck, near Otley, Yorks. It is stated to be difficult to place in the succession on account of drift obscured country and faulting. The writer suggests that it should be correlated with the second E2a faunal band in Leitrim and not with the Marchup Marine Beds as suggested in the memoir. Hudson (1944, p. 234) correlates this fauna with the E2a horizon in Alport Dale. There is an abundance of K. scaliger as in Hudson’s E2a horizon at Alport, also Pseudamusium and crinoidal debris. Most of the specimens of Cravenoceras are too fragmentary to be of value and those of E. bisulcatum from this locality are not good. The specimens identified as Posidonia cf. P. membranacea are the forms now referred to as P. corrugata elongata subsp. nov., P. J. YATES: NAMURI AN OF SLIEVE ANIERIN 419 which is abundant on Slieve Anierin in the second E2a band. Chaenocardio/a footii is also present in both places. A similar fauna is described in the Bradford and Skipton memoir (Stephens et al. 1953, p. 29) from the Washburn Valley near Leathley, Yorks., and is also correlated with the Marchup Marine Beds, but the writer would correlate it with the second faunal band in E2a in Leitrim. A large slab from 280 yards W. 8° S. of St. Oswald’s Church, Leathley, Yorks., shows K. scaliger which is indistinguishable from specimens in the second faunal band in E,a on Slieve Anierin and Eludson and Cotton’s E2a horizon at Alport. Hudson (1944, p. 234) correlates this fauna with E2a in Alport Dale, and Stubblefield (/'// Stephens et al. 1953, p. 94) agrees that it may be lower than the Marchup Marine Beds. A discussion between Hudson and Stubblefield (1945, pp. 135—7) over the possible correlation of the Cockhill Limestone with the Weston Marine Beds in the Washburn Valley can be considered at this point in the fight of the Slieve Anierin succession. E. bisulcatwn from the Weston Marine Band at Leathley (GSM WE947) is compared with E. bisulcatwn erinense from the second faunal band in E2a on Slieve Anierin, and the E. bisulcatwn from the Cononley Beck Edge Marine Band with E. bisulcatwn ferrimontanum from the same band on Slieve Anierin. Both subspecies occur within one continuous fossiliferous band and it is therefore suggested that this second faunal band in E.,a should be corre- lated with the Weston and the Edge Marine Bands. The Warley Wise marine band material has not been seen, but the lamellibranch fauna fisted by Bray (1927, p. 53) appears to be similar to that found in the second band in E2a. Hudson believes, on faunal and stratigraphical evidence, that this band is below the Weston Marine Band. It may be that the two subspecies of E. bisulcatwn which occur within the one band on Slieve Anierin have elsewhere led to the conclusion that two very different levels were being seen. The writer would suggest that the Warley Wise, the Edge and the Weston Marine Bands should all be correlated with the second faunal band in E2a on Slieve Anierin and that the lower faunal band corresponds with the Cockhill Limestone. This would support Stubblefield’s suggestion that the Weston Grit is earlier than the Marchup Grit and that the Grassington Grit is earlier than either. Although the second faunal band in E2a on Slieve Anierin does not yield as abundant examples of Cravenoceras as the lower band, it does yield a few which are referred to Cravenoceras cf. C. gairense. In the material at the Geological Survey Museum from Cononley Beck listed by Stephens et al. (1953, p. 25) is a Cravenoceras with an acute- edged open umbilicus; however, most of the specimens have been rejected and thrown away and the few fragments now left do not show the umbilicus but only simple Craveno- ceras ornament. Since C. cf. C. gairense is typical of the second faunal band on Slieve Anierin it would be a valuable additional fine of evidence if it could be found in some of the marine bands in the Pennines which it is suggested should be correlated with this level. Some specimens have been found at the Geological Survey Museum which had been identified as Cravenoceras cf. C. holmesi, presumably because the um- bilical edge appears to be raised; however, in C. gairense there are three spiral ridges around the umbilicus which make it unmistakable. The specimens now assigned to the latter species, e.g. GSM JS1479, 1491, and 1492, were collected from a road-cutting on the east side of the road 520 yards west-north-west of Crickton, Llanrhidian, Glam. E e C 674 420 PALAEONTOLOGY, VOLUME 5 (Survey Book 29, p. 267). Specimens GSM JS1 121 and 1117 were collected from a stream in Moorlakes Wood, 250 yards north-east of Courthouse Farm, Ilston, Glam., and are also the same species. A further link with the Slieve Anierin horizon exists in the presence of Dunbarella sp. (GSM JS1113) in the Glamorgan fauna; it is believed to be the same species as that on Slieve Anierin and shows a large number of ribs and no definition of the anterior ear by a furrow. (e) Cravenoceratoides bisati and Ct. edalens e fauna, lowest E2b. The lowest E2b subzone, that of Ct. bisati, contains dominant Ct. edalense and less common Ct. bisati. The most Slieve Anierin ( this paper ) Greenhow Mining Area (. Dunham and Stubblefield 1944) Simonseat Anticline near Skipton (Hudson 1939) Lancaster Fells ( Moseley 1954) Alport Dale ( Hudson and Cotton 1943) Ct. nititoides E. rostratum Productus hibernicus Weberides cf. W. shunnerensis C. holmesi A. tenuispirale A. tenuispirale Pace Gate Beck (Tonks 1925) Ct. nititoides Productus sp. ? Ct. stellarum C. holmesi Anthracoceras beds E. rostratum at 300-6 ft. (re- ferred to as the Ct. nitidus level by authors) few horizons with faunas Dominant E. bisulcatum Colsterdale Birk Gill nitidus worth leitrimense ; rare Ct. nitidus C. subplicatum Limestone no record of Limestone A. aff. A. disco ides C. cf. C. holmesi Limestone Cravenoceras of cowlingense group, Ct. recording Dominant Ct. edalense. any C. aff. C. holmesi lirifer and rare 354-60 ft. rare Ct. bisati Grit of these species Red Scar Grit C. cf. C. subplicatum Red Scar Grit Ct. bisati Roeburndale Grit Ct. edalense table 4. Suggested correlations between the fauna above the grit on Slieve Anierin and ones of similar age in northern England. common lamellibranch is Posidonia corrugata elongata. The succeeding beds contain very abundant but poor forms attributed to Cravenoceras subplicatum. Hudson (1945, pp. 2, 4) states that there are two horizons within the Ct. bisati sub- zone, a lower faunal band with C. subplicatum and an upper with Ct. bisati. The various sections described by Hudson (1944, pp. 233-41) all appear to lead to this conclusion. On Slieve Anierin the maximum abundance of Ct. edalense is definitely beneath C. subplicatum and only unfossiliferous horizons occur beneath the former. The Marchup Marine Beds are described in the Bradford and Skipton memoir (Stephens et al. 1953, pp. 26-29) as characterized by Ct. bisati, and presumably in part at least they belong to P. J. YATES: NAMURIAN OF SLIEVE ANIERIN 421 the Ct. bisati subzone and can therefore be correlated with the beds immediately above the grit on Slieve Anierin. It is to this level that the beds from Holbeck and the Wash- burn River, which have already been discussed, have been ascribed in the memoir. Hudson and Cotton (19456, pp. 9, 10), in describing the Ct. bisati subzone in the Edale Valley in Derbyshire, have not been able to determine the relative positions of the two faunal bands of the subzone. In the Lancaster Fells, Moseley (1954, pp. 432-3) has not included C. subplicatum in his faunal list but includes C. cf. C. cowlingense group and Ct. lirifer; these two forms are associated together in four bands within the subzone with no distinction into lower and upper. There can be no doubt of the order of succession in these beds on Slieve Anierin. (/) Cravenoceratoides nitidus subzone. The base of this subzone is characterized by a small E. bisulcatum which has constrictions and is described as E. bisulcatum leitrimense subsp. nov. It does not conform with E. bisulcatum varicata Schmidt (1934, p. 449, fig. 29 and p. 445). At this level only fragments of Cravenoceratoides ornament have been found, which show clearly the forking and the asymmetrical nature of the lirae, sug- gesting that they represent either Ct. nitidus or Ct. nititoides. It seems probable that they are fragments of the former, but for some reason the species does not appear to have been as common in this area as elsewhere, whereas the Eumorphoceras is relatively abundant in the shales at this level. A few rare specimens of C. holmesi have been found slightly lower than E. bisulcatum leitrimense , but are more abundant above this level. In Alport Dale, Derbyshire, Hudson and Cotton (1943, p. 162) record a Ct. nitidus band from a depth of 300-6 feet and a Ct. edalense horizon at 354-60 feet. Between these two depths there were few horizons with faunas worth reporting, and there is no record of anything comparable with E. bisulcatum leitrimense. The material collected by the same authors (19456, pp. 9, 10) in Edale has also been examined at the Geological Survey Museum but is extremely poor and there is no indication of this horizon. At the Geological Survey Museum there are a few imperfect specimens which are believed to be the same subspecies; GSM Da 1593, 1594, and 1599 were collected in a section on the left bank of the stream, 150 yards to the south-east of Low Stubbing and 820 yards N. 11° W. of Holy Trinity Church, Cowling, Yorks. Stubblefield has commented in Geological Survey Book 28, p. 20, that Da 1599 shows constrictions with two to three ribs between them and that the ribs resemble short stubby plications as are seen in some of the Scottish examples of E. bisulcatum. Dunham and Stubblefield (1944, pp. 239-41) describe the Colsterdale Limestone as abounding in Ct. nitidus at the level of the Colsterdale Marine Beds in the Greenhow mining area, and with E. bisulcatum rare in the shales at this level. The latter is described as the variety with short stout ribs which elsewhere characterizes this horizon. GSM CS853 and CS859 (Survey Book 35, p. 51) from locality 25 of Dunham and Stubblefield have been examined, but are too poor and fragmentary to compare satisfactorily with E. bisulcatum leitrimense. However, one very interesting connexion that can be established is that GSM CS891, identified as Cravenoceras cf. C. holmesi , from the Colsterdale Marine Band in a stream section 300 yards west of Ivin Waite, west of Pateley Bridge, Yorks., is now attributed to Anthracoceras tenuispirale, and this species first appears on Slieve Anierin at the level 422 PALAEONTOLOGY, VOLUME 5 of E. bisulcatum leitrimense and soon becomes the dominant species. It is suggested therefore that the Colsterdale Limestone corresponds to the E. bisulcatum leitrimense level on Slieve Anierin. In the Pateley Bridge area Ct. nitidus is only abundant in the limestone whereas Eumorphoceras occurs in the shales; it is therefore possible that the lack of suitable limestone-forming environments in the Slieve Anierin area at this time may be connected with the scarcity of Ct. nitidus. Dunham and Stubblefield (1944, p. 241) correlate the Colsterdale Marine Beds in general terms with the Marchup Marine Beds of the Brad- ford and Skipton area. There is, however, no record in the Greenhow area of beds with Ct. bisati; the Colsterdale Marine Beds succeed the Red Scar Grit and their fauna of Ct. nitidus has already been discussed. The limits of the Marchup Marine Beds do not appear to be exactly defined, but the Slieve Anierin succession suggests that the level of the Colsterdale Marine Beds is above the Ct. bisati subzone and at the lower level within the Ct. nitidus subzone. The Ct. nitidus fauna seen in the Greenhow area has not been seen in the Bradford and Skipton country. (g) Anthracoceras tenuispirale fauna. A. tenuispirale, which was first described from the Ct. nitidus subzone in the Namurian of Belgium by Demanet (1941, pp. 148-9, pi. 6, fig. 18; pi. 7, figs. 1, 2), is abundant on Slieve Anierin and can now be demonstrated in beds of this age in the Pennine area. The high magnification needed to detect the spiral ornament suggests the possibility that this species may well have been overlooked in the past and may have been identified as either A. pauci/obum or A. glabrum , or, like the Colsterdale specimen, as C. holmesi. Moseley (1954, pp. 433-4) records Anthracoceras of the paucilobum group in the Anthracoceras beds above the Ct. nitidus limestone in the Lancaster Fells, but un- fortunately, no illustrations of the fossils are given and the material does not appear to be available ; it can only be suggested, therefore, that as this is the same level as that with abundant material on Slieve Anierin, Moseley’s Anthracoceras specimens may be A. tenuispirale. (h) Cravenoceras holmesi fauna. At this level C. holmesi has only been seen as external impressions in which the ridge around the umbilical edge in the adult is seen as an impressed groove. The species occurs rarely lower in the succession just below the E. bisulcatum leitrimense horizon and a few internal moulds have been found at this lower level showing the rim around the umbilicus and fragmentary sutures. The crushed im- pressions which are so common above the A. tenuispirale horizon are inferior and mostly not very large specimens. In this species the ridge is not a decided feature until the adult stage. A larger specimen, in which the ridge must have been a very marked feature, is seen as an impression in GSM Zgl349, collected from Meerbrook, Staffs. The position of C. holmesi in the succession has been the subject of some discussion. Hudson (1945, p. 4) placed the C. holmesi fauna beneath the Ct. nitidus horizon on evidence from Greenholes Beck in the Lancaster Fells. Moseley (1954, pp. 432-3) dis- agreed with this and believed that Hudson (1944, p. 238) did not record the fauna of the nitidus limestone in the Greenholes Beck succession and was led astray by the rare occurrence of Ct. nitidus above the level with C. holmesi. On Slieve Anierin it appears that if the level of E. bisulcatum leitrimense is correctly correlated with the Ct. nitidus horizon elsewhere (and the evidence is distinctly in favour of this contention) then the P. J. YATES: NAMURI AN OF SLIEVE ANIERIN 423 maximum abundance of C. holmesi is definitely above the horizon of Ct. nitidus. How- ever, it must be pointed out that the species is already scantily present slightly lower than E. bisulcatum leitrimense although its period of dominance is higher in the succession. Moseley (1954, pp. 432-5) erected the subzone of C. holmesi above the Ct. nitidus subzone and below a subzone of ?C7. stellarum. The evidence for the latter does not seem to be strong, since Moseley states that badly preserved specimens of ICraveno- ceratoides (possibly Ct. stellarum ) were obtained from a thick calcareous band. He also states that Hudson may have had better material and that the horizon is tentatively regarded as the base of the Ct. stellarum subzone. Hudson (1945, p. 4) mentions another section in the River Noe Valley in Edale, Derbyshire, where it is possible to determine the relative positions of Ct. nitidus and C. holmesi. This section was described by Jackson (1927a) and subsequently by Hudson and Cotton (19456, pp. 9, 10); the latter describe a higher fauna including Ct. nitidus , C. cf. C. holmesi , and E. bisulcatum var. above shales with C. holmesi and C. cowlingense. The material available at the Geological Survey Museum, however, is all so poor and fragmentary that it was found impossible to compare it with any of the goniatites from Slieve Anierin. Specimens GSM Zi968 and 969 are, however, believed to be Productus hibernicus, which occurs in a rich faunal band above the C. holmesi beds on Slieve Anierin. GSM Zil487 also shows a Productus and a trilobite pygidium. Hudson and Cotton (19456, p. 9, footnote) state that Bisat (in lift., 1945) considered that Ct. nititoides was an important member of this fauna, which they refer to the Ct. nitidus subzone. (/) Cravenoceratoides nititoides fauna. Above the beds with Ct. holmesi on Slieve Anierin occurs the most prolific fossil band in the succession, rich in goniatites and lamel- libranchs but also containing the brachiopods P. hibernicus and rare Orbiculoidea nitida, and the trilobite Weberides cf. W. shunnerensis. Specimens of Ct. nititoides are extremely abundant and it is virtually impossible to distinguish between them and the holotype (GSM 49964) collected from Pace Gate Beck, near Blubberhouses, Yorkshire (see Bisat 1932, pi. 2, fig. 2). Tonks (1925, pp. 251-2) originally collected from this locality and includes trilobite remains in his faunal list. E. bisulcatum is recorded as rare. Unfortunately it is now im- possible to collect from this locality and there is little material in the Geological Survey Museum collections apart from the holotype of Ct. nititoides and the paratypes GSM Z1 5779-86. On the evidence of Ct. nititoides and the trilobite remains it is suggested that this band should be correlated with the Pace Gate Beck exposure. Hudson (1945, footnote, p. 5) states that the shale exposure in Pace Gate Beck is an isolated one, that it occurs towards the top of the Birk Gill Shales, and that it is not possible at this locality to locate its position in relation to other Arnsbergian faunas. The fauna given by Hud- son (1939, p. 329) for the Birk Gill Limestone appears to be nearer to that of the Colster- dale Limestone, with common Ct. nitidus , whereas the Pace Gate Beck fauna is obviously distinct and the inference from Hudson’s remarks (1945, footnote, p. 5) is that it is higher in the Birk Gill Shales than any of the faunas described by him from these beds. It is unfortunate that these exposures are so incomplete but the succession on Slieve Anierin establishes the position of this band dominated by Ct. nititoides about 40 feet above the horizon with E. bisulcatum leitrimense and very rare Ct. nitidus, and below the first appearance of N. nuculum. 424 PALAEONTOLOGY, VOLUME 5 In Alport Dale Hudson and Cotton (1943, p. 162) record a fauna at a depth of 300-6 feet; this fauna has been examined and specimen GSM Zh955 is considered to belong to E. rostratum sp. nov., which occurs at the Ct. nititoides level on Slieve Anierin. It shows the same merging of the ribs into fine striae at about half-way across the flanks and the same extremely prominent lingua in the striae. At this level Ct. nititoides is present as well as Ct. nitidus, trilobite remains and Productus sp. ; all the evidence favours the correlation of this level in the borehole with the Ct. nititoides band on Slieve Anierin. An interesting occurrence at the Ct. nititoides level on Slieve Anierin is the presence of Euchondria aff. E. levicula Newell (1937, p. 107), previously only identified in American deposits. Newell (in lift., 1960) agrees that the Slieve Anierin specimens are extremely close to the American material. The species is a very abundant member of the lamelli- branch fauna at this level. No information is available as to its stratigraphical level in the American succession in terms of the British goniatite succession, but it is an Upper Carboniferous (Pennsylvanian) species. It is considered significant that Tonks (1925, p. 252) included Aviculopecten aff. A. dissimilis Fleming in the Pace Gate Beck faunal list. This species has a left valve with radial ornament and a right valve with concentric ornament only, suggesting that his specimens were the same as the lamellibranchs associated with Ct. nititoides on Slieve Anierin. The Euchondria levicula specimens from Slieve Anierin are better preserved, and show the nature of the ligamental area as well as the discrepant ornament of the two valves. This is further evidence of the postulated correlation of the two horizons. 3. Germany Arnsberg, Westphalia. The Namurian succession of the Arnsberg area in Westphalia, Germany, has been described by Schmidt (1934, pp. 440-61), and there is close corre- spondence with the sequence of faunas on Slieve Anierin. The E. pseudobilingue beds are not subdivided (op. cit., pp. 445-6) and Schmidt states that the forms of this species are extremely variable and not always easy to separate from E. bisulcatum. The example of the former species which has been figured, however (op. cit., p. 446, fig. 1), resembles E. pseudobilingue s.s. with rather wavy ribs as seen at localities L2 1(5)4 and L23(4)l on Slieve Anierin. Dimorphoceras scaliger Schmidt (op. cit., p. 446, fig. 2), now Kazakhoceras scaliger, is found at this level in Ireland also, where it is associated with Cravenoceras aff. C. malhamense and first appears a little above E. pseudobilingue s.s. The drawing of Chaenocardiola haliotoides (Roemer) (op cit., p. 446, fig. 7) shows only twenty-one ribs whereas this species is supposed to have rather large rib counts. It looks very much like an immature specimen of Chaenocardiola footii, which on Slieve Anierin first appears at about the level of E. pseudobilingue s.s. Schmidt does not be- lieve that the German forms are the same as the British species, but his drawing does not seem to support his argument. Patteisky (1929, p. 20, pi. 17, fig. 13) figured Chaenocardiola haliotoidea and the large number of ribs appears to conform with the original description of the species. It is associated, however, with Sagittoceras discus (Roemer), now Girtyoceras discus (Roemer), which in England is described from high B2 (Moore 1946, pp. 397-8). On Slieve Anierin the only specimens which have been referred to this species have been collected from the Ct. nititoides level in E2. P. J. YATES: NAMURIAN OF SLIEVE ANIERIN 425 The figures given for Cravenoceras cf. C. Jeion (Schmidt 1934, p. 446, fig. 3) and for C. cf. C. malhamense are too poor for comparison and according to Schmidt the genus is rarely found. He mentions fish remains about 10 mm. below the described fauna and which were attributed by Aldinger (1931, pp. 190-3) to Coelacanthus stensioi Aldinger (now Rhabdoderma stensioi (Aldinger) (Demanet 1941, pp. 1 66—8)) and Coelacanthus sp. Similar remains have been found at L20(16)2 on Slieve Anierin, where they are known to be in El5 and occur above L20(16)l, where a high C. leion zone fauna is exposed, including E. medusa. The beds of E2 age at Arnsberg allow a more detailed subdivision, and the fauna (op. cit., pp. 446-8) can broadly be correlated with the E2a beds on Slieve Anierin. It is difficult to suggest any closer comparisons within E2a as some of Schmidt’s figures suggest features that are rather generalized. The figure of E. bisulcatum (op. cit., p. 447, fig. 12) shows several bifurcating ribs like E. bisulcatum grassingtonense ; but the ribs appear to be rather geniculate and in fact like those of E. bisulcatum erinense subsp. nov. from the second faunal band in E2a on Slieve Anierin. It would be unwise to do more than point out that the figure certainly resembles E. bisulcatum s.l., which occurs below the grit on Slieve Anierin. The next horizon at Arnsberg with C. edalense (op. cit., p. 448) obviously represents the beds seen immediately above the grit on Slieve Anierin. The specimen illustrated in fig. 23, p. 448 would now be assigned to Ct. bisati, since there is repeated bifurcation of the lirae. On Slieve Anierin this form is considerably less common than Ct. edalense. Forms like Cravenoceras sp. (fig. 26, p. 448) and C. cf. C. leion (fig. 25, p. 448) are said to occur beneath the beds with Ct. bisati, but Schmidt’s figures are small and poor, and it has not been found possible to compare them with forms from Slieve Anierin. Schmidt (1934) refers fig. 28, p. 448 to Posidoniella membranacea (now Caneyella membranacea) but it is now thought to be Posidonia corrugata elongata subsp. nov., which is an abundant associate of Ct. edalense on Slieve Anierin, whereas C. mem- branacea does not extend beyond Ej. The next horizon contains Anthracoceras paucilobum and Cravenoceras nitidum (now Ct. nitidus), and probably corresponds with the horizon of E. bisulcatum leitrimense on Slieve Anierin. The Eumorphoceras at this level is E. bisulcatum varicata Schmidt, which has similarities with leitrimense, but the latter has fewer ribs between the con- strictions. A. paucilobum has not been seen with absolute certainty from this horizon on Slieve Anierin, but A. tenuispirale appears with leitrimense and soon becomes the dominant member of the fauna. The occurrence of Posidoniella laevis Brown at this level in Germany corresponds with a similar appearance at a comparable level on Slieve Anierin. Such forms are now referred to P. variabilis erecta subsp. nov. Ct. nitidus is rare at this level on Slieve Anierin but the horizon of leitrimense is believed to be the same as that at which Ct. nitidus is common in other localities, e.g. the level of the Colsterdale Limestone in the Greenhow area, near Grassington in Yorkshire (Dunham and Stubblefield 1944, pp. 239-41). The succeeding beds at Arnsberg, containing Cravenoceras holmesi and C. cowlingense are believed to be the equivalent of the C. holmesi beds on Slieve Anierin, where C. holmesi is abundant just above the A. tenuispirale beds and beneath a band dominated by Ct. nititoides. Fig. 40, p. 449 (Schmidt 1934) is very like the evolute examples of C. holmesi on Slieve Anierin, where, however, it has not been found associated with any 426 PALAEONTOLOGY, VOLUME 5 undoubted examples of C. cowlingense. Posidoniella variabilis also occurs at this level on Slieve Anierin. There is no record at this point in Schmidt’s succession of any band comparable with the nititoides horizon on Slieve Anierin. The next level described by him consists of shales with C. stellarum (now Ct. stellarwn) and C. nititoides (now Ct. nititoides). He describes spiral sculpture on some of these forms, which he otherwise ascribes, on umbi- lical diameter, to the two species just mentioned, assigning specimens in which the umbilicus is completely closed to Nucidoceras nuculum , and within which zone these forms are considered to be the lowest fauna. Spiral sculpture has not been seen in any of the Slieve Anierin specimens of Ct. nititoides and no specimens of N. nuculum or of Ct. stellarum have been collected. On Slieve Anierin there is therefore definite evidence for a Ct. nititoides band below the N. nuculum zone which is considered by Hudson (1945, p. 2) as the top of the E2 stage, but is placed by Bisat (1928) and also by Stephens et al. (1953, p. 95) as the lowest division of H. On the whole, excluding small differences in identification partly due to poor material, there appears to be a close resemblance between the sequences in the geographically widely separated areas of Westphalia and Leitrim. Edelburg. Bisat (1950, p. 14) has compared the basal Ex succession from Edelburg, near Menden, Germany, described by Ruprecht (1937), with the succession near Wiswell, Lancashire; Carla Beck, near Skipton, Yorkshire; the Whinney Gill Reservoir, near Skipton; and the Alport Dale boring, Derbyshire. The form referred to by Ruprecht as E. pseudobilingue (1937, p. 272, pi. 10, fig. 7) is now assigned to E. pseudo cor onula and does not differ from specimens in the C. leion zone on Slieve Anierin. Posidonia trape- zoedra (op. cit., pp. 272-3, pi. 10, figs. 9, 10) is very abundant near the top of Ej on Slieve Anierin but was first described by Ruprecht from lower P2 beds with Goniatites granosus. E. tornquisti (Wolterstorff), which Bisat (1950, p. 20) considers may be the same as Eumorphoceras sp. form A Moore, and which was originally described from Magdeburg (Wolterstorff 1899, pp. 34-36, pi. 2, figs. 12-14), is a very rare form on Slieve Anierin. Here again there appears to be close similarity between the Irish and German faunas. 4. Poland and Czechoslovakia Schwarzbach(1936, pp. 442-3) described several species and varieties of Phillipsiafrom Silesia. Most of the specimens came from Horizons \a-d, II, and III at the top of the Ostrauer Schichten. Patteisky (1936, p. 4) has tabulated the main marine bands in these beds and described some of the goniatites. He correlates (op. cit., pp. 24—26) these younger bands with the Ct. nitidus beds in England. He figures Cravenoceras (cf.?) C. nititoides Bisat (op. cit., pi. 1, figs, la, b) but the plates are too poor to allow com- parison with specimens of Ct. nititoides from Slieve Anierin. Even Patteisky describes this form as Cravenoceras sp. (p. 14) and the identification would thus appear to be far from certain. His specimen, however, is from Horizon IV6 and most of Schwarzbach’s trilobite records are from the younger marine horizons. It seems probable that these discrepancies are due to rather varying interpretations by different authors of some of the English species, and also to the poor material available. Susta (1928, p. 421) records Phillipsia mucronata M‘Coy, P. eichwaldi Fischer, P. P. J. YATES: NAMURIAN OF SLIEVE ANIERIN 427 mladeki Smetana, and Griffithides acuminatus Roemer from the Gaebler Horizon, the youngest band in the Ostrauer Schichten. He also records Eumorphoceras sp. at this level but does not figure the species. On Slieve Anierin Weberides cf. W. shunnerensis is associated with Ct. nititoides, which occurs about 40 feet above the level of E. bisul- catum leitrimense; the latter is believed to represent the level of Ct. nitidus elsewhere and is taken as the base of the Ct. nitidus subzone. It therefore appears that the Silesian trilobites occur at closely similar horizons to the Slieve Anierin specimens. Schwarzbach (1936, p. 427) also records trilobites from Horizon X in the Ostrauer Schichten, which is placed by Patteisky (1936, pp. 21-23) in IY /IS. He records Sudeticeras ostraviensis from this horizon. Moore (1950, p. 33) has commented that so little appears to be known about this species that comparison with others is valueless. No suture is known and Patteisky admits that it can be confused with A. pcnicilobum. The other goniatites recorded at this level are Cravenoceras sp., C. (? Sudeticeras) latecostatum Patteisky (op. cit., p. 13, pi. 1, fig. 1 1), Dimorphoceras sp., and ?A. pauci/obum. It is difficult to place this fauna in terms of the Slieve Anierin succession, but it must lie near the P2/E1 boundary. It is interesting that the only other trilobites found on Slieve Anierin occur at this level, which is devoid of goniatites, but must lie either just below or just above the base of Ex. Patteisky (1933, p. 44, pi. 2, fig. 30) also describes Phi/lipsia acuminatus Roemer from this level in the Sudetenland. Trilobites thus appear to have been widespread elements in the faunas at certain levels in the lower Namurian. 5. Belgium Basal Namurian faunas from the area around Namur are described by Demanet (1941 ; map, p. 53). The E. pseudobilingue beds are divided into a lower and an upper division, the former about 10 metres thick and fossiliferous, the latter about 125 metres thick and practically without fossils. The fauna of the lower division given by Demanet (1941, p. 22) is a rich one, but rather surprisingly includes only three goniatite species. Only one form of E. pseudo- bilingue is described and figured (op. cit., pp. 135-6, pi. 5, figs. 11—14) and it does not resemble any of the forms of that species collected on Slieve Anierin, but has features much more reminiscent of the specimens of E. bisulcatum which occur below the grit. C. leion (op. cit., pp. 140-1, pi. 5, figs. 21—23) is stated to be associated with E. pseudo- bilingue; the third goniatite is Anthracoceras sp. There is in addition a large nautiloid and lamellibranch fauna, together with a few brachiopods, conodonts, and fish remains. Apart from C. leion there are no records of any of the abundant goniatites of Exa found on Slieve Anierin. Crushed specimens of Cravenoceras are notoriously difficult to deal with and, judging from the photographs, it would be difficult to be certain of the specific determination of these specimens. An illustration of the suture-line, which is only described by Demanet (op. cit., p. 141), would be desirable for comparison with that figured by Bisat (1930, p. 29). The sharply acute edge to the umbilicus, which can usually be seen on the specimens of C. leion from Slieve Anierin, does not appear to be a feature of the Belgian material. The photographs of Eumorphoceras appear to be far more conclusive and do not resemble any of the Ex species on Slieve Anierin. Demanet includes Posidonomya ( Posidonia ) membranacea, now Caneyella mem- branacea, in his faunal list, and on Slieve Anierin this form does not extend beyond Ex deposits. Unfortunately the material is not figured, but Demanet has figured the species 428 PALAEONTOLOGY, VOLUME 5 in a previous publication (1938, pi. 10, figs. 5-11) from P2 deposits and his conception of the species obviously concurs with that of the writer. He remarks (1941, p. 80), how- ever, on the variation in obliquity of the species within E2. This is interesting since the writer believes that there is a more oblique form of the species than that which Demanet figured from P2 levels, and it occurs particularly abundantly on Slieve Anierin at the level of Cravenoceras aff. C. malhamense. However, in E2 beds there is an elongated variety of Posidonia corrugata which appears often to have been mistaken in faunal lists for C. membranacea. Without figures it is impossible to tell to which of these two forms Demanet’s material should be assigned. I believe the lower form to be C. mem- branacea and since it is associated with C. aff. C. malhamense it is an Ei form. I refer the higher forms to P. corrugata elongata subsp. nov. and this is most abundant in E2a deposits and in E2b, but I have not seen undoubted examples at lower levels. The evi- dence for the Ej age of these beds does not therefore appear to be conclusive, and indeed Demanet’s illustrations of Eumorphoceras suggest otherwise. Demanet apparently believed that the E. bisulcatum which he found with Ct. edalense in the lower Nmlb beds was E. bisulcatum s.s., and he does not distinguish beds in which E. bisulcatum is the dominant goniatite beneath the Ct. edalense beds. All the available evidence from successions described elsewhere, notably Arnsberg (Schmidt 1934, pp. 446-7), Alport Dale (Hudson and Cotton 1943, pp. 162-3), and the Edale Anticline, Derbyshire (Hudson and Cotton 1945, p. 10), indicate that this zone of E. bisulcatum s.s. exists below the zone of Ct. nitidus (the basal subzone of the latter is correlated with Demanet’s Ct. edalense beds). Demanet does not suggest that his succession is possibly incomplete. This apparent gap in the Belgian succession appears to the writer to support the view that the beds assigned to El5 certainly from the level at which the figured specimens of E. pseudo- bilingue were collected, are probably more correctly assigned to E2. Dorlodot and Delepine (1930, p. 58, pi. 8, fig. 4) described and figured E. pseudo- bilingue from Bioul in Belgium. They apparently only had one specimen, which was extremely crushed and distorted. It appears from the figure to be too poor and incon- clusive to be compared with the Slieve Anierin material. The E. pseudobilingue beds (Zone de Bioul, Nmla) of Belgium are succeeded by the Zone de Malonne, Nmlb, which is divided into lower, middle, and upper. The lower division (Nmlb inferieur) is characterized by C. edalense and is apparently present at all the Nmlb localities tabulated by Demanet (1941, p. 56). The description of this species given by Demanet (op. cit., pp. 141-2) mentions only one bifurcation of the lirae at the umbilical edge, which indicates that it is not Ct. bisati. Demanet’s plates (op. cit., pi. 6, figs. 1-3), although a little indistinct, appear to be very like Ct. edalense as col- lected above the grit on Slieve Anierin. At this level on Slieve Anierin E. bisulcatum does not occur, but Demanet (1941, p. 56) lists this species at four of the Nmlb localities. However, the single figure (pi. 5, fig. 15) of the form from this level is so poor that it is impossible to compare it with any of the Slieve Anierin specimens. Posidonia aff. P. wapanuckensis is also recorded from many of the localities by Demanet, but is not figured from this level; it has previously been figured from P2 beds (Demanet 1938, pp. 117-18, pi. 10, figs. 14-18). Demanet (1941, p. 81) comments that the specimens in Nmlb are far larger than the American ones and frequently difficult to distinguish from P. corrugata. This sugg;sts that these specimens are the same as the P. J. YATES: NAMURIAN OF SLIEVE ANIERIN 429 forms from this level on Slieve Anierin described as P. corrugata gigantea subsp. nov. and P. corrugata elongata subsp. nov., and associated there with Ct. edalense. Ramsbottom (1959, p. 405) believes that Caneyella wapanuckensis (Girty) from the Caney Shale of Oklahoma includes at least two species. In his opinion Girty’s figure 9 (1909, pi. 3) is very like Posidoniella variabilis , and figs. 6, 7, and 1 1 (on the same plate) are all reminiscent of Posidonia corrugata. This tends to support the present contention that Demanet’s specimens are probably incorrectly ascribed to P. aff. wapanuckensis. Demanet (1941, p. 29) includes A. tenuispirale in his fauna but not in the lower Nmlb faunal and locality chart (pp. 55—56) and it is therefore presumed not to be a very prominent member of this fauna. This coincides with the evidence on Slieve Anierin where the species is seen only rarely beneath E. bisulcatum leitrimense, but becomes more abundant later. Dimorphoceras sp. and A. paucilobum complete Demanet’s goniatite fauna for this level. The latter has not been seen at this horizon on Slieve Anierin; specimens attributable to Anthracoceras are present but it is difficult to be sure of the species. D. looneyi occurs on Slieve Anierin at a horizon a little above the beds with Ct. edalense. The nautiloid and lamellibranch faunas given by Demanet are far larger than those on Slieve Anierin. The fauna of the succeeding middle Nmlb or C. nitidum beds (of Demanet, but now Ct. nitidus ) comes from 6-10 metres of fossiliferous beds at the base, which are succeeded by unfossiliferous strata. The fossils from the entire thickness are treated as one fauna so that it is impossible to make exact correlations with Slieve Anierin. Ct. nitidus is rare on Slieve Anierin, but the level at which it is abundant elsewhere is believed to be represented by E. bisulcatum leitrimense. From what is regarded as the same level in Germany Schmidt has described E. bisulcatum varicata , and Demanet has likewise described and figured this subspecies in Belgium (1941, pp. 138-9, pi. 5, figs. 16, 17). He describes it as having strong constrictions, about six in a whorl, and with seven ribs between them. This is obviously different from leitrimense, although the general aspect of Demanet's figures is rather like some of the less clearly preserved Slieve Anierin material. Griffithides serotinus Demanet is recorded at locality Bioul 23, but appears to be dis- tinct from Weberides cf. W. shunnerensis which occurs on Slieve Anierin. The trilobite level in Belgium is associated with Ct. nitidus and E. bisulcatum varicata and appears to be lower than the horizon on Slieve Anierin, which yields abundant Ct. nititoides and E. rostratum sp. nov. There is apparently no record of a C. holmesi fauna in Belgium nor have C. cowlingense or C. subplicatum been recorded. Posidoniella variabilis is abundant in Belgium as on Slieve Anierin and the form in- cluded in Demanet’s lists as P. laevis Brown is thought to be the same as P. variabilis erecta subsp. nov. Posidonia corrugata is not included in the lists given by Demanet but is very abundant on Slieve Anierin. Posidonomya aff. P. wapanuckensis is included, however (as in the lower Nmlb fauna), and the more correct designation of this form has already been discussed. A. tenuispirale is abundant both in Belgium and on Slieve Anierin. It is very abundant just above E. bisulcatum leitrimense on Slieve Anierin, but higher in the succession it is replaced by C. holmesi. In Belgium it presumably occupies a similar position since it occurs with Ct. nitidus. Since there is no record of the succeeding C. holmesi fauna or the Ct. nititoides — E. rostratum band, it may be that the unfossiliferous beds which succeed the latter on Slieve Anierin are present at a lower level in Belgium. 430 PALAEONTOLOGY, VOLUME 5 The succeeding ‘Nmlb superieur’ is characterized by Nuculoceras nuculum and is therefore higher in the sequence than any of the beds exposed on Slieve Anierin, but corresponds with the successions at other localities. Dorlodot and Delepine (1930, pp. 57—58, pi. 1, figs. 1-5) figured specimens of E. bisulcatum from the Namur area; they are not like any of the Slieve Anierin forms, but as they are said to be associated with N. nuculum, A. glabrum, and Ct. nitidus (Homo- ceras nitidum of these authors) it seems likely that more than one form is included in this specific determination; also, since N. nuculum is referred to, some at least must occur at higher levels than any which are exposed on Slieve Anierin. 6. North America There is evidence that there was open communication between the seas of western Europe and North America at least during uppermost Visean and Lower Namurian times. Several American formations contain goniatite species that are very similar to those known in western Europe. Miller and Youngquist (1948, p. 656) and Youngquist (1949, pp. 282-3) have claimed that faunal elements which are distinct in the European succession are found associated together in the Barnett Shale of Texas, the Caney Shale of Oklahoma, and the White Pine Shale of Nevada. Youngquist (op. cit., p. 282) states that Eumorphoceras, Girtyo- ceras, and Goniatites s.s. occur in direct association in the White Pine Shale. Gordon (1957) described goniatites from northern and eastern Alaska, and for the first time in North America recorded the genus Sudeticeras ( S . alaskae Gordon). G. crenistria Phillips, G. cf. G. granosus Portlock and Cravenoceras sp. are also recorded but Gordon has no evidence to suggest an overlap of the ranges of Goniatites and Cravenoceras. The more obvious similarities between some of the species in the Slieve Anierin succession and those in American formations will be briefly outlined, but it seems impossible at present to establish accurate correlations based on the succession of faunas. The fauna of the Caney Shale of Oklahoma (over 1,000 feet thick) was described by Girty (1909), and is important as it includes the type material of E. bisulcatum Girty (1909, pp. 68-70, pi. 11, figs. 15-19a). The subspecies erinense and ferrimontanum from Slieve Anierin are both believed to be very close to E. bisulcatum s.s. In Ireland, England, Belgium, and Germany such forms appear to be typical of the lowest zone in E2, that of E. bisulcatum s.s. The resemblance of Caneyella wapanuckensis (Girty) (1909, pp. 34-35, pi. 3, figs. 6-11) to at least two species, namely Posidoniella variabi/is and Posidonia corrugata , has already been referred to. The former has been observed on Slieve Anierin throughout Ex and E2 deposits and in the lower P2 beds, and the latter becomes abundant at about the middle of E2. The genus Caneyella was erected on the abundant specimens of this lamellibranch in the shales, and species like C. nasuta (p. 37, pi. 3, figs. 12-14) appear to be very like C. membranacea, particularly fig. 14. Adelphoceras meslerianum Girty was originally described from the Caney Shale but is now attributed to Girtyoceras meslerianum. This genus is not known to occur in the rather poor P^Pa faunas of Slieve Anierin. Moore (1946, pp. 405-6, pi. 23, fig. 6) described GSM 72716 from a Pja level in the Bowland Shales of the River Ribble, Dinckley, Lancashire, and was satisfied that there was no valid distinction between this specimen and GSM For. 1867 (op. cit., pi. 23, fig. 3) collected from the Caney Shale. P. J. YATES: NAMURIAN OF SLIEVE ANIERIN 431 Goniatites newsomi Smith from the Caney Shale (Girty 1909, pp. 62-63, pi. 12, figs. 11, 11 a) also occurs on Slieve Anierin very near the top of P2, and has been recorded by Moore (1936, p. 185, pi. 2, figs. 6, 12) from the Bowland Shales. The species was re- ferred to the genus Lyrogoniatites by Miller and Furnish (1940, pp. 368-9), who erected a subspecies L. newsomi georgiensis, which differs from the typical L. newsomi in that the whorls are lower and broad and therefore the conch more nearly globular. In crushed shale material it is difficult to detect such a difference, but the close similarity of Moore’s plates of the English material, the Slieve Anierin material, and the figures of the Ameri- can form, whether newsomi ox georgiensis, is convincing evidence of the close relationships of all these forms. Padget (1953, pp. 22, 23) listed Neogiyphioceras subcircularis from the G. granosus zone of P2. On Slieve Anierin only undoubted G. granosus has been collected but the former genus is known from America also and is listed by Miller and Furnish (1940, p. 361) as a form known from Oklahoma, Arkansas, Texas, P2 of England, Ireland, Belgium, France, Germany, and also Morocco and northern Algeria. Gastrioceras caney- anum Girty is the genotype of Paragoniatites and is considered by Bisat (1955, p. 16) to be very close to Neogiyphioceras. There are therefore several forms from the Caney Shale which are known at specific levels in the succession of faunas established elsewhere. The type specimens of Leiorhynchus carboniferus polypleurus come from the Moore- field Shale of Arkansas (Girty 1911) and are indistinguishable from those collected on Slieve Anierin about 3 feet below G. granosus at the base of P2, and also forms figured and described by Demanet (1938, pp. 83-87, pi. 8, figs. 9-14). Demanet’s figured speci- mens are from upper V3c, which is equivalent to P2 in age. However, he records this species from the E. pseudobilingue zone, in which it has not been found on Slieve Anierin. Girty (191 1, pp. 103-4, pi. 14, fig. 4) identified one specimen from the Moorefield Shale as E. bisulcatum ; only a single specimen, described as senile, was available. The identifica- tion was later amended to Girtyoceras limatum (Miller and Faber) by Miller and Furnish (1940, pp. 364—6, pi. 47, figs. 6-12). This form appears to be similar to E. medusa which occurs near the top of the C. leion zone on Slieve Anierin and above E. pseudocoronu/a, to which it is believed to be related. Miller and Youngquist (1948, pp. 662-5) described examples of E. bisulcatum from the Barnett formation in central Texas. They also figured a new species, E. plummeri (op. cit., pp. 665-7, pi. 100, figs. 1-4, 20, 21), and compared it with the specimen (GSM 72603) figured by Moore (1946, pi. 22, fig. 3), which was associated with N. nuculum and collected from Samlesbury Bottoms, River Darwen, Lancs. There is no evidence for the N. nuculum zone on Slieve Anierin and no specimens of Eumorphoceras from the moun- tain appear to conform with E. plummeri, although E. rostratum sp. nov. displays certain points of similarity. Girtyoceras meslerianum (Girty) is also described from the Barnett formation, which, in terms of the European succession, apparently has species as widely separated as the base of Px and the N. nuculum zone, assuming that E. plummeri is correctly compared with the Samlesbury Bottoms material. Gordon (1960, pp. 140—3) described a new genus, Paracravenoceras, from the Barnett Shale of Texas, and which also occurs rarely in the Caney Shale of Oklahoma. P. ozarkense is abundant in the Fayetteville Shale of Arkansas and P. barnettense is common in the Chainman Shale of Utah. The genus is said to be common in, and re- stricted to, the Lower Eumorphoceras zone. It has sinuous transverse growth lamellae 432 PALAEONTOLOGY, VOLUME 5 in the young and a distinctive form of ventral lobe in the suture. Nothing resembling this genus has been seen on Slieve Anierin. Another form which so far appears to be peculiar to America is E. girtyi Elias. It was attributed by Elias (1956, pp. 130-2, pi. 6, fig. 7) to an Ex age, and described as possessing an intra-ventral carina and a reticulate pattern of striae on the ventro-lateral area. Nothing comparable occurs in Ex on Slieve Anierin. However, the type is said to be associated with E. plummeri , which was originally likened by Miller and Youngquist (1948, pp. 665-7) to the forms associated with N. nuculum collected by Moore from Samlesbury Bottoms, Lancs. It is therefore difficult to know at which level any similar species might occur in the Slieve Anierin or other western European succession. Only a cross-section illustrates the original description by Elias, but material from the Redoak Hollow Formation of southern Oklahoma has been figured by Elias (1958, p. 32, pi. 3, figs. 10-13); unfortunately these figures do not shed any light on the problem. One interesting connexion with American lamellibranch species has been established with the discovery of Euchondria aff. E. levicula in the highest faunal band on Slieve Anierin. Newell (in lift., 1960) has confirmed the close similarity between the Slieve Anierin specimens and the described material from the Hushpuckney Shale of Iowa and the Labette Shale of Missouri. 7. Morocco Delepine (1941) described some Namurian goniatites from Morocco, including (p. 79) a very small specimen (unfortunately not figured) which he tentatively assigned to E. bisulcatum. He also described and figured (op. cit., p. 77, pi. 6, figs. 4-7) C. nitidum (Phillips); the specimen illustrated in fig. 4 was collected with N. nuculum and A. glabrum. Judging from the plate the ornament appears to be rather fine and hairlike, and not like the normal asymmetrical lirae of typical Ct. nitidus. Figs. 5-7 are too poor for compara- tive purposes. C. africanum Delepine (op. cit., pp. 75-76, pi. 6, figs. 1-3) appears to be a form which in its somewhat evolute aspect suggests C. holmesi. Hudson (1941, p. 282) has com- mented on the wide distribution of the Cravenoceras group to which this species belongs in the Eumorphoceras beds of Europe, North Africa, and North America, and also that some of the species described from America may in fact be synonyms of the European species. Delepine also refers to the resemblance of C. africanum to C. holmesi and C. cowlingense. There is certainly a resemblance to the specimens of C. holmesi from Slieve Anierin and to those figured from Arnsberg by Schmidt (1934, p. 449, fig. 40). Conclusion As more evidence becomes available a remarkable picture of the extent of the Namu- rian goniatite faunas emerges and the great similarity of specimens from locations geographically far removed from each other is striking. Local geographical variants obviously occur. E. bisulcatum, for example, both from E2a levels on Slieve Anierin and from similar levels in England, is very close to E. bisulcatum s.s. from the Caney Shale, and yet these forms are not quite the same. Similarly, amongst the lamellibranchs, Euchondria aff. E. levicula is very close to the American forms, but is not quite the same. These differences, however, are fine ones and the overall picture is of a basic popula- tion which is remarkably uniform over a very wide area. The appearance of trilobites at P. J. YATES: NAMURIAN OF SLIEVE ANIERIN 433 specific levels in the succession both in western Ireland, England (Pace Gate Beck, the Alport boring, and in the Edale Valley), and in Silesia, is also striking proof of the wide- spread nature of certain horizons. The geographical extent and remarkable abundance of the Posidonia corrugata group is also a feature of this part of the succession. P. becheri was often extremely abundant in P! times but the success and vigour of the corrugata group surpassed it both in time range and range of variation. In E1 only Caneyella approached it in abundance but above Ex this genus is no longer seen. This widespread uniformity of the goniatite-lamellibranch faunas is not confined to the narrow time range with which this work has been concerned. The foundations of all such studies were firmly laid by Bisat (1928, pi. 6) for the whole of the Namurian and now the correlations established by him are being endorsed and amplified in greater detail both vertically and horizontally. As methods of illustrating specimens improve, it becomes increasingly obvious that although language and other national difficulties may often obscure the true features of the specimens and lead to varying interpretations, often of the same species, good well- reproduced photographs smooth out such difficulties and bear silent witness to the wide- spread nature of these goniatite and lamellibranch species, and may truly be a more accurate substitute for the actual specimens than words alone. APPENDIX 1 . Fossiliferous localities on Slieve Anierin a. West of Slieve Anierin leitrim 20(16) (text-fig. 3) 1. North bank of stream 500 yds. west of Glen Bridge; best material 3-4 ft. above stream level. Eumor- phoceras medusa, Pseudamusium praetenuis. Eja. 2. South bank of stream 450 yds. east of Glen Bridge. 10 ft. section of friable shales. Coelacanthus sp. Eya.. leitrim 20(12) (text-fig. 3) 1 . At un-named bridge on Dowra track 1 ,600 yds. north of Glen Bridge ; calcareous mudstone at stream level; Sudeticeras cf. S. newtonense. Basal 3 ft. of the overlying 10-ft. section of papery shales yield Caneyella membranacea, C. membranacea horizontalis subsp. nov. High P2. 2. 15 ft. shale section in stream, with prominent hard band. High P2. b. North of Slieve Anierin; Stony River leitrim 20(8) (text-fig. 2) 1. 25-ft. shale section 100 yds. upstream from point where 500-ft. contour crosses the Stony River; at base Obliquipecten costatus sp. nov., C. leion, Eumorphoceras cf. E. sp. form A Moore. E,a. 2. 40-ft. section 100 yds. east of 1 ; shales at base yield Pseudamusium praetenuis, E. medusa, Kazakho- ceras sp. Ex a. 3. 50-ft. section of friable dark-grey shales on south bank near point where 600-ft. contour crosses Stony River; fauna collected on scree includes Posidonia corrugata, P. trapezoeclra, Pseudamusium sp., Kazakhoceras sp. Similar fauna collected in situ on opposite side in gully higher up hillside. E,a. leitrim 21(5) (text-fig. 2) 1. Right bank 250 yds. upstream from confluence of 1st tributary; 25-ft. section; lower reaches barren, but fallen shales yield P. corrugata, P. trapezoeclra, Kazakhoceras sp. Low Ejb. 434 PALAEONTOLOGY, VOLUME 5 2. Few yds. upstream from 1; band in situ ; solid beds at base yield P. corrugata, P. trapezoedra, Kazakhoceras sp., Eumorphoceras cf. E. angustum. Low Ejb. 3. 200 yds. downstream from confluence of 2nd tributary; hard black shales 3 ft. above stream. P. corrugata, P. trapezoedra, Kazakhoceras sp. Low Ejb. 4. 150 yds. downstream from confluence of 2nd tributary; 20-ft. section; lowest 2-4 ft. yield E. pseudobdingue s.s., P. corrugata, P. trapezoedra, Chaenocardiola footii; succeeding 6 in. yield differ- ent fauna, E. pseudobdingue C, C. footii, P. corrugata. Low E,b. Opposite this section fallen blocks from upper part of section yield C. membranacea, K. scaliger, Cravenoceras aff. C. malhamense. EjC. 5. First north bank section upstream from confluence of 2nd tributary; 3 ft. of papery shales above a hard calcareous mudstone yield C. membranacea, K. scaliger, C. aff. C. malhamense. EjC. 6. 150 yds. upstream from 5 on left bank; 10-ft. section. Cravenoceras sp., Chaenocardiola footii. Exc. 7. 100 yds. upstream from 6; hard shales at base. Posidonia lamellosa. E2a. 8. North bank 175 yds. downstream from confluence of 3rd tributary; 15-20 ft. of thicker bedded shales (overlying friable unfossiliferous black shales), forming high continuous sections on either side of valley until 3rd tributary. P. lamellosa, P. corrugata, C. footii, Cravenoceras cowlingense, E. bisulcatum grassingtonense. E2a. 9. At confluence of 3rd tributary; same beds and fauna as at 8, but at stream level. 10. Right bank of 3rd tributary 220 yds. upstream from confluence; 4 ft. 6 in. of fossiliferous shales exposed at top of section. E. bisulcatum erinense subsp. nov., E. bisulcatum ferrimontanum subsp. nov. (much less common), K. scaliger, Anthracoceras glabrum, Cravenoceras cf. C. gairense, P. corrugata, P. corrugata elongata subsp. nov., C. footii, Dunbarella aff. D. elegans, Pseudamusium sp., Stroboceras subsulcatus, crinoidal debris. High E2a. 1 1 . Right bank of Stony River 300 yds. upstream from confluence of 3rd tributary and along the river to the grit escarpment; 4 ft. of shales at stream level with E. bisulcatum ferrimontanum subsp. nov., K. scaliger, Cravenoceras cf. C. gairense, C. footii, P. corrugata, P. corrugata elongata subsp. nov., Dunbarella aff. D. elegans, Dunbarella sp., Pseudamusium sp., Stroboceras subsulcatus, crinoidal debris. High E2a. c. South-east of Slieve Anierin leitrim 21(14) (text-fig. 3) Doherty Stream East 1. In western tributary 10 yds. west of 2; 5 ft. of sandy shales. Chaenocardiola footii. High E,b. 2. In western tributary above fork at 3 ; P. corrugata, P. trapezoedra. Low Ejb. 3. Bed of stream at fork, and in both banks of eastern tributary for about 5 ft. from stream bed. Eumorphoceras cf. E. angustum, Kazakhoceras sp., P. corrugata, P. trapezoedra. Low Ejb. 4. In eastern tributary above fork; 20 ft. of shales; at base C. footii, P. corrugata. Low Ejb. 5. North bank a few yds. before fork; 2 ft. of shales exposed 6-8 ft. above stream. Fauna as at 3. Low Ejb. 6. North-east bank; 30 ft. high section of shales, top 10 ft. inaccessible. At about 20 ft. from base, E. medusa, Pseudamusium praetenuis, P. trapezoedra, Kazakhoceras sp. At about 10 ft. from base, P. trapezoedra, P. corrugata, Kazakhoceras sp. Exa. 7. South-west bank 20 yds. upstream from 6; 4-6 ft. of shales. E. medusa, Pseudamusium praetenuis, ? Stroboceras sp. Eaa. 8. South-west bank 100 yds. upstream from 9, and a few yards beyond the last field boundary; 6-ft. section; soft mudstone 3-4 ft. above stream with E. pseudocoronula, E. rota, C. leion, Kazakhoceras sp. Eja. 9. North-east bank about 380 yds. upstream from bm 93 10; 8 ft. of thinly leaved black shales. Caneyella membranacea, C. membranacea horizontalis subsp. nov., Sudeticeras sp. High P2. 10. South-west bank about 300 yds. upstream from bm 93 10. Pj. 11. South-west bank at bend in stream 120 yds. upstream from 12; sandstones with occasional thin sandy shales. Chonetes sp., Dunbarella sp., Leiorhynchus sp., obscure Goniatites sp. P,. 12. Section upstream from bm 93 10; upstream from massive calcareous horizon on lip of upper waterfall, a few yds. above waterfall at 13; alternations of friable shales and calcareous mudstones; 3 ft. of mudstones on north-east bank yield P. becheri, obscure Goniatites cf. G. striatus group, Orbiculoidea sp., ? worm burrows, Mourlonia striata. Px. P. J. YATES: NAMURIAN OF SLIEVE ANIERIN 435 13. To north of bridge (bm 931-0), 250 yds. along track to north-east from road to old coal level from the Ballinamore road; 2 ft. of calcareous mudstone overlying 3 ft. massive limestone yields P. becheri, Goniatites cf. G. striatus group, ? worm tubes, indet. brachiopods. P,. 14. Stream section 40 yds. south-east of bridge; 6 in. mudstone underlying 3 ft. black limestone forming a small waterfall yields Goniatites cf. G. striatus group, crinoidal debris, abundant worm burrows. P, . 15. Stream section 75 yds. south-east of bridge; mudstone band near base of 6-ft. section. Goniatites cf. G. striatus group, indet. gastropods. Pi. Doherty Stream West 16. Long overgrown exposure under right bank of tributary 350 yds. south of bm 1249-8; C. leion. E,a. 17. 20 yds. upstream from 18 ; 1 ft. of shales with Dunbarella sp. and P. becheri overlying 9 in. mudstone with P. becheri. P,. 18. Few yds. upstream from 19; hard band at 19 near base of section. P. becheri. P:. 19. Few yds. upstream from 20; 4-5 ft. of mudstone with P. becheri; in middle of section is harder horizon with Productus sp. Px. 20. Stream sections at bridge where track south-west from bm 986-1 crosses stream near ruined cottages on 900-ft. contour; below bridge, 40 ft. of black bituminous limestone; above bridge, 4 ft. of mud- stones with P. becheri dominant overlying 18 in. massive limestone, and then 2 ft. of mudstones with P. becheri and very abundant worm tubes. PL. d. South of Slieve Anierin: Aghagrania River and tributaries leitrim 23(8). Aghagrania River (text-fig. 4) 1. West bank 150 yds. north-north-west of Aghagrania Bridge; black limestone with Dunbarella aff. D. elegans. P,. 2. East bank 8 yds. upstream from 3; 1 ft. of shale. P. becheri, G. striatus s.l., D. aff. D. elegans, Mour- lonia striata. Px. 3. East bank at stream level 100 yds. north of Aghagrania Bridge, just beyond stepping-stones; shales yield Goniatites aff. G. falcatus, P. becheri, D. aff. D. elegans. Pi. 4. East bank at stream level 30 yds. upstream from 5, and separated from latter by calcareous mudstone horizon; 1-2 ft. of shale with Goniatites striatus s.l., Archaeocidaris urii, indet. pleurotomariid gastro- pod. Pj. 5. East bank at stream level just north of Aghagrania Bridge; 1 ft. of shale with G. striatus s.l., Chonetes sp. Pj. 6. West bank 60 yds. south of Aghagrania Bridge, below house on east bank ; 4 ft. mudstones. Thrinco- ceras cf. T. hibernicum, orthoconic nautiloids, crinoidal debris, indet. pleurotomariid gastropod. Pi. 7. North-west bank 150 yds. south-west of Aghagrania Bridge; 2-3 ft. of mudstone overlying massive limestone horizon yields Thrincoceras cf. T. hibernicum, P. becheri, Productus sp., indet. brachiopods, orthoconic nautiloids. Px. 8. South-east bank opposite 7. Same fauna. P^ leitrim 23(4) (text-fig. 4) 1. At bridge over western branch of 1st tributary, 130 yds. to north of fork; large slabs of dark grey shale. E. pseudobilingue s.s., P. corrugata. Low Ejb. 2. 20 ft. shale section in 1st tributary, 500 yds. upstream from confluence. P. trapezoedra, E. medusa sinuosum. E,a. 3. West bank of 1st tributary, 450 yds. upstream from confluence; 15 ft. section. P. trapezoedra. Eja. 4. 10 ft. section 50 yds. north of 5; fauna from stream level to 6 ft. C. membranacea horizontalis subsp. nov., Kazakhoceras sp. Eta. 5. West bank of 1st tributary, 350 yds. upstream from confluence; 20 ft. shales; at 15 ft. from base C. leion, P. corrugata, P. trapezoedra, Kazakhoceras sp., E. medusa. E^. 6. East bank opposite 7, but at slightly lower horizon; highest material collected at 8 ft. above stream level, with E. pseudobilingue A, C. leion ; at 5 ft. C. leion, E. cf. E. pseudocoronula; at 4 ft. C. leion. Eja. F f C 674 436 PALAEONTOLOGY, VOLUME 5 7. West bank of 1st tributary 250 yds. above confluence; 3 ft. of shales at about 10 ft. above stream bed. E. pseudobilingue A, C. leion. E^a. 8. West bank of 1st tributary 200 yds. above confluence; 3-ft. shale section. Obliquipecten costatus sp. nov., C. leion, E. pseudocoronula. E,a. 9. East bank 25 yds. downstream from 8 ; collection 3 ft. from top of 8-ft. high shale section overlying calcareous mudstone. C. leion, O. costatus sp. nov. Eja. 10. Narrow ravine in 3rd tributary 150 yds. north of confluence, just south of waterfall over calcareous band; friable shales with C. leion, O. costatus sp. nov. Exa. 1 1. Narrow ravine 50 yds. south of 10; shales at base with O. costatus sp. nov. Eja. 12. South bank of Aghagrania River 30 yds. downstream from confluence of 3rd tributary; 2 ft. of shales with P. corrugata, Pseudamusium praetenuis. E^. 13. South bank 160 yds. upstream from confluence of 2nd tributary; 4 ft. shales. P. corrugata, C. membranacea horizontalis subsp. nov., Kazakhoceras sp. P2. 14. South bank 40 yds. upstream from confluence of 2nd tributary; 15 ft. shales; at base C. mem- branacea, C. membranacea horizontalis subsp. nov., Sudeticeras sp.; few yds. to east a soft clay-like band a few ft. above base yielded P. corrugata. P2. 15. South bank of Aghagrania River between 1st and 2nd tributaries; 20 ft. shale section; collections from 3 levels — (1) 6 ft. from base, west side, P. corrugata, Kazakhoceras sp.; (2) 10 ft. from base, C. membranacea horizontalis subsp. nov.; (3) 15 ft. from base, Chonetes sp., Lingula cf. L. parallela, P. corrugata, Obliquipecten costatus sp. nov., trilobite remains. (1) and (2) P2, (3) probably Exa. Scree material, not in situ, in front of section yielded E. pseudocoronula, C. leion. Eja. 16. South bank between 1st and 2nd tributaries; shales 3 ft. 6 in. above stream level, Lyrogoniatites newsomi georgiensis, C. membranacea ; at base calcareous mudstone with imperfect brachiopods. P2. 17. 480 yds. north-north-west of Aghagrania Bridge, on east of track, and 40 ft. above stream; 6-8 ft. of friable shales, Pseudamusium praetenuis, P. corrugata, Chonetes sp., trilobite remains; soft clayey band in centre of section, P. corrugata, Kazakhoceras sp., C. membranacea horizontalis subsp. nov. P2. 18. East side of stream at lower horizon than 17; 5-6 ft. of shales. Dunbarella aff. D. elegans, Sudeti- ceras sp., Coleolus sp. P2. 19. 450 yds. north-north-west of Aghagrania Bridge; 30-ft. section in westerly loop of stream; collec- tion from 3 levels — (1) 3 ft. from base, Leiorhynchus carboniferus polypleurus ; (2) 6 ft. from base, G. granosus, Sudeticeras cf. S. crenistriatum, Coleolus namurcensis; (3) 20 ft. from base, Sudeticeras sp., G. granosus, C. namurcensis, Kazakhoceras sp., Orthoceras cf. O. calamus de Koninck, Dun- barella aff. D. elegans, C. membranacea, C. membranacea horizontalis subsp. nov., P. corrugata, Chaenocardiola bisati sp. nov. P2. 20. 350 yds. north-north-west of Aghagrania Bridge ; rich goniatite band in soft mudstone. Sudeticeras cf. S. crenistriatum, Thrincoceras cf. T. hibernicum, C. namurcensis. Product us sp., Mourlonia striata. P,. LEITRIM 24(1) (text-fig. 4) 1. West bank 100 yds. north of farmhouse, near point where 800-ft. contour crosses river; 3 ft. shales about 6 ft. above stream. E. pseudocoronula, E. pseudobilingue A, E. rota, C. leion, P. praetenuis , Chaenocardiola bisati sp. nov., C. membranacea horizontalis subsp. nov., Kazakhoceras sp. E^. 2. Embayment on south side of river about 100 yds. north-north-east of right-angled bend in road; 6 ft. of thin-bedded decalcified sandy rocks with obscure brachiopods. P2. 3. North bank 400 yds. west-south-west of right-angled bend in road; 6 ft. of decalcified beds; obscure brachiopod moulds only. P2. 4. South bank 1,100 yds. upstream from confluence of 3rd tributary; thin-bedded arenaceous limestone with crinoidal remains. P2. 5. South bank 500 yds. from confluence of 3rd tributary; upper 2 ft. limestone bed in soft black shales yields Productus sp. and indet. brachiopods. P2. 6. South bank 330 yds. upstream from confluence of 3rd tributary. G. granosus, Sudeticeras cf. S. crenistriatum, indet. brachiopods. P2. 7. North bank 300 yds. upstream from confluence of 3rd tributary; 3 ft. shales. Sudeticeras sp., P corrugata, Pseudamusium sp. P2. 8. North bank 250 yds. upstream from confluence of 3rd tributary; 15-20 ft. shale section on east side at 8 ft. from base yields C. membranacea horizontalis subsp. nov. ; at base on western side Chonetes P. J. YATES: NAMURI AN OF SLIEVE AN1ERIN 437 sp., Sudeticeras sp., Leiorhynchus sp., P. corrugata; 3 ft. above base, Sudeticeras sp., Coleolus namur- censis; 9 ft. above base, Sudeticeras sp., P. corrugata. P2. 9. South bank 230 yds. upstream from confluence of 3rd tributary; 6 ft. black shales. G. granosus, Sudeticeras sp., C. membranacea, C. membranacea horizontalis subsp. nov., Obliquipecten costatus sp. nov., Dunbarella aff. D. elegans. P2. 10. North bank 200 yds. upstream from confluence of 3rd tributary; 6 ft. shale section; near base, P. corrugata, Sudeticeras sp. P2. LEITRIM 21(13) (text-fig. 3) 4. East side of Aghagrania River, 780 yds. east from bm 1163-1, 100 yds. upstream from 6; 2 ft. of hard fossiliferous shales overlain by 4 ft. of friable unfossiliferous shales. E. bisulcatum ferrimon- tanum subsp. nov., Kazakhoceras scaliger, Craveuoceras cf. C. gairense, P. corrugata, P. corrugata elongata subsp. nov., Chaenocardiola footii, Dunbarella aff. D. elegans, Stroboceras subsulcatus, Pseudamusium sp., crinoidal debris. High E2a. 5. Western valley side 50 yds. beyond last field boundary and 650 yds. east of bm 11631; 6 ft. of slabby shales resting on friable unfossiliferous shales; fauna as at 6. Low E2a. 6. East bank 750 yds. east of BM 1163-1; 16 ft. of shales (underlying 20 ft. of friable unfossiliferous shales) with Craveuoceras cowlingense, E. bisulcatum grassingtonense, C. footii, "IDimorphoceras sp., Posidonia lamellosa, Stroboceras subsulcatus, plant remains. Low E2a. 7. 15-ft. shale section on west bank 950 yds. north of right-angled bend in road; lower 6 ft. with C. membranacea, Chaenocardiola footii, Craveuoceras aff. C. malhamense, K. scaliger, Actinopteria persulcata. EjC. 8. West bank just above waterfall near point where 1,000-ft. contour crosses stream; 15 ft. of sandy shales; at base P. corrugata, C. footii, E. pseudobilingue C, Cycloceras purvesi. High E,b. 9. West side of waterfall 850 yds. north of right-angled bend in road; 6 ft. of shales. P. corrugata, P. trapezoedra, Eumorphoceras cf. E. angustum, Kazakhoceras sp. Low Exb. 10. East side of waterfall at 9, high in bank; 8 ft. of shales; same fauna. Low Ejb. leitrim 20(16) (text-fig. 3) 3. Western branch of 1st tributary 360 yds. north of fork; 3-ft. shale section, upper 2 ft. sparsely foss- iliferous. Probably EjC. 4. Shale sections in both banks below house, 30 yds. south of 3. Probably E^. e. Top of Slieve Anierin ( above grit ) leitrim 21(9) (text-fig. 3) 1 to 14. Several small valley-like exposures, varying in height from 10 to 30 ft.; only 13 has a stream (headwaters of Stony River). Basal beds in valleys 1 to 10 are in shales with Ct. edalense, P. cor- rugata, Craveuoceras cf. C. subplicatum. Basal beds at 1 1 are at a higher level and yield Dimorpho- ceras sp., those at 12 P. corrugata, and at 13 C. holmesi and C. cf. C. subplicatum. E2bl. 15. Valley 150 yds. north-east of 16, and 400 yds. south-east of trig. stn. 1,628 ft.; lower exposure of hard shales at top of 15 ft. scree yields Ct. cf. Ct. bisati, Craveuoceras sp., P. corrugata; larger 30 ft. shale exposure upstream, at base C. cf. C. subplicatum, Ct. bisati. E2bl. 16. Small exposure of shales in hillside, 400 yds. south-south-east of trig. stn. 1,628 ft. A. tenuispirale. E2b2. 17. Outcrop 300 yds. north-west of valley 1 (L21(9)26). Lower horizon with Ct. edalense, C. cf. C. cowlingense, P. corrugata. E2bl. Higher horizon (at about same level as 18) with P. corrugata, A. tenuispirale. E2b2. 18. Small shale outcrop 1 50 yds. north-west of Valley 1 (L21 (9)26). P. corrugata , Anthracoceras sp. E2b2. 19. 150 yds. north-east of L21(13)3; fauna at lower level P. corrugata, Posidoniella variabilis, Dimor- phoceras sp.; at higher level E. bisulcatum leitrimense subsp. nov., P. corrugata, Cravenoceratoides sp. (with asymmetrical lirae). E2b2. 20. 50 yds. north-west of bend in grit escarpment, at bottom of narrow corridor overlain by thick peat; large slabs of fossiliferous shale overlying friable unfossiliferous shales. Ct. edalense, Ct. bisati, P. corrugata elongata subsp. nov. E,bl. 21. South-west side of wide valley with small stream 120 yds. north of 20; scree makes collecting difficult. Craveuoceras holmesi occurs sparsely below E. bisulcatum leitrimense subsp. nov. Also 438 PALAEONTOLOGY, VOLUME 5 occurring A. tenuispirale, P. variabilis, P. variabilis erecta subsp. nov., Dimorphoceras sp., P. cor- rugata, P. corrugata elongata subsp. nov. E2b2. 22. 75 yds. north-east of 21 and 200 yds. north-east of bend in grit escarpment; higher beds than at 20, but not as high as those at 21. P. corrugata, Posidoniella variabilis erecta subsp. nov. E2bl. 23. Valley 4, the most south-easterly of four prominent valleys, and containing the most complete succession E2bl to 3; the lowest beds (corresponding to the first fossiliferous beds above the grit at 20) contain Ct. edalense, Ct. bisati, P. corrugata elongata subsp. nov., and P. corrugata, E2bl. (See Table 2.) 24. Valley 3; basal beds seen are in a rich band of E. bisulcatum leitrimense subsp. nov.; thereafter succession as in Valley 4, but collecting easier. E2b2 to 3. (See Table 2.) 25. Valley 2; highest faunal band, with Ct. nititoides, E. rostratum sp. nov., &c., overlain by unfos- siliferous shales and then flagstones. E2b3. 26. Valley 1 ; Ct. nititoides horizon exposed about 15 ft. above stream; overlying succession as in Valleys 3 and 4. E2b3. 27. Deep east- west valley with stream, 650 yds. south of trig. stn. 1,628 ft. Basal beds in horizon of E. bisidcatmn leitrimense subsp. nov., E2b2. The Ct. nititoides horizon occurs at the eastern end, E2b3. 28. East-west valley containing small stream 600 yds. south of trig. stn. 1,628 ft. Basal beds in leitri- mense horizon, E2b2; exposures end before Ct. nititoides band. 29. Small dry east-west valley 75 yds. north of 28; 20 ft. of shales with A. tenuispirale, P. corrugata, C. holmesi, P. variabilis erecta subsp. nov. ; succession starts above leitrimense level and does not reach the Ct. nititoides band. E2b2. leitrim 21(13) (text-fig. 3) 1. Hillside exposure 100 yds. east of Valley 4 (L2 1 (9)23) ; 2 ft. of shales with Dimorphoceras ( Paradimor - phoceras) cf. D. looneyi, P. corrugata. E,bl. 2. Several small shale exposures in hillside 1 50 yds. east of 1 ; Ct. edalense, P. corrugata elongata subsp. nov. E2bl. 3. Long valley with tiny stream mile east of Valley 4 (L21(9)23), and exposing slightly lower beds; at entrance 20 ft. of beds are overlain by 6-8 ft. of shales with Ct. edalense, P. corrugata, P. corrugata elongata subsp. nov.; higher 8-10 ft. of shales contain P. corrugata, Cravenoceras cf. C. subplicatum. E2bi. 2. New specimen and locality numbers for Yates (1961) Yates (1961) New Yates (1961) New (a) Specimens'. E. medusa St. Ri. 2.23 7018 E. medusa Agh. 8.1 7027 St. Ri. 2.26 7019 sinuosum Agh. 8.2 7028 Doh. 6B.10 7020 Agh. 8.4 7029 7021 counterpart Agh. 8.10 7030 Doh. 6B.14 7022 St. Ri. 2.22a 7031 St. Ri. 2.24 7023 E. rota Agh. 21.3 7012 7024 counterpart Doh. 50.1 7013 Doh. 6B.7 7025 Agh. 21.4 7014 St. Ri. 2.25 7026 (b) Localities'. E. medusa Doh. 6 L2 1 ( 14)6 E. rota Agh. 21 L24( 1)1 St. Ri. 2 L20(8)2 Doh. 50 L2 1 (1 4)8 E. medusa Agh. 8 L23(4)2 sinuosum St. Ri. 2 L20(8)2 (c) Explanation of Plate 6 : E. medusa Doh. 6B.10 7020 E. medusa Agh. 8.1 7027 St. Ri. 2.23 7018 sinuosum Agh. 8.2 7028 E. pseudo- Agh. 21.3 7213 E. rota Agh. 21.3 7012 coronula Doh. 50.1 7013 P. J. YATES: NAMURIAN OF SLIEVE ANIERIN 439 3. Notes on preservation Goniatites. The goniatites are most commonly preserved as external moulds or impressions from which plasticine replicas showing the original external aspect of the fossils can easily be made. In a true internal mould of a goniatite there should be sutures visible as, for example, in many of the sutured internal moulds described by Currie (1954) and also in most of the material collected by Moore from various localities in England and Ireland and deposited at the Geological Survey Museum. The specimens in shale from Slieve Anierin, however, have been preserved under far less favourable conditions and sutures are scarcely ever preserved. Frequently only the long living chamber is clearly visible, so that the internal mould does not reveal any sutures. The term internal mould is used, with the proviso that the specimens usually lack the sutures of true internal moulds. The internal moulds would show the minor features on the internal surface of the shell in reversed or negative relief. But at the same time they would also show, due to the thinness of the shell itself (and in apparent contradiction of the strict definition of the term mould), the major structural features of the shell, e.g. strong ribs, ventro-lateral ridges and furrows, in positive relief. It is also possible occasionally for some of the finer features of the test, seen in reverse in the external moulds or impressions, to be impressed to a certain extent onto the unsutured internal mould. The same phenomenon is seen also in some of the lamel- libranchs. The constrictions seen in such a species as Eumorphoceras pseudocoronula, although more prominent on the internal moulds, are also visible on the exterior of the test. In the external impressions the con- strictions are seen in reverse as ridges. On the internal moulds they are more strongly defined and seen as strong furrows. In some goniatites, however, the constrictions are entirely due to an internal thick- ening of the shell and not visible externally. The specimens of Goniatites granosus collected from P2 show constrictions very strongly on the internal moulds but they are not visible on the outside of the shell. Lamellibranchs. As with goniatites external moulds or impressions are common but in several genera internal moulds are equally abundant. After death and the subsequent decay of the soft parts it would be natural for the valves to part and for internal moulds to be formed. Many specimens of the genus Euchondria, for example, show the multiple ligament pits along the dorsal margin and must therefore be internal moulds. There is an added complication in these specimens in that although they are basically internal moulds the external ornament of the valve has to a certain extent been impressed on to the internal mould during the compaction of the sediment. This method of preservation is not un- known, as Newell (1937, pi. 19, fig. 1) figures similarly preserved valves from America and uses the term ‘subinternal mould’. The same process may also have happened occasionally in other genera; for example, the ornament in both Pseudamusium and Obliquipecten often has a curiously muted aspect, which may be due to its impression onto a presumably smooth internal mould. Trilobites. In the case of Weberides from the highest faunal band, some of the pygidia are preserved as external moulds or impressions of the dorsal surface of the exoskeleton and therefore show the convex rim as a depression surrounding the pleurae, which are in reversed relief. However, other pygidia are obviously moulds of the ventral surface of the exoskeleton, since they show surrounding the pleurae (which are in apparent positive relief) a concave area which bears fine striations parallel with the margin; this is in fact a mould of the convex doublure. REFERENCES aldinger, h. 1931. Uber karbonische Fische aus Westfalen. Palaont. Z. 13, 186-201. baily, w. h. 1860. Explanation to Sheet 142. Mem. geol. Surv. Ireland, 18-19, figs. 9 a-e. beushausen, L. 1895. Die Lamellibranchiaten des rheinischen Devon mit Ausschluss der Aviculiden. Abh. preuss. geol. Landesanst. 17, 364-5 bisat, w. s. 1924. The Carboniferous goniatites of the north of England and their zones. Proc. Yorks, geol. Soc. 20, 40-124, pi. 1-10. 1928. The Carboniferous goniatite zones of England and their continental equivalents. Congr. Avanc. Et. Stratigr. carbonif. Heerlen, 1927, 117-33, pi. 6, 6a. 440 PALAEONTOLOGY: VOLUME 5 bisat, w. s. 1930. On Cravenoceras leion sp. nov., the basement goniatite of the Namurian, Upper Carboniferous. Trans. Leeds geol. Ass. (20), 28-32. — ■ — 1932. On some Lower Sabdenian goniatites. Ibid. 5, 27-37, pi. 1, 2. • 1933. The Carboniferous goniatites of the neighbourhood of Tenby. Proc. Geol. Ass., Lond. 44, 412-14. 1934. 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Stuttgart. gill, w. D. 1947. On the Upper Bowland Shales in Carla Beck, near Skipton, Yorks. Proc. Leeds pliil. lit. Soc. 5, 60-64. girty, G. H. 1909. The fauna of the Caney Shale of Oklahoma. Bull. U.S. geol. Surv. 377, 5-106, pi. 1-13. 1911. The fauna of the Moorefield Shale of Arkansas. Ibid. 439, 1-148, pi. 1-15. Gordon, m. 1957. Mississippian cephalopods of northern and eastern Alaska. Prof. Pap. U.S. geol. Surv. 283, 1-61, pi. 1-6. P. J. YATES: NAMURIAN OF SLIEVE ANIERIN 441 Griffith, R. 1818. Geological and mining survey of the Connaught coal district in Ireland. Dublin. hind, w. 1896-1905. A monograph of the British Carboniferous Lamellibranchiata. Palaeontogr. Soc. (. Monogr .), 1, 1896-1900; 2, 1901-5. hodson, F. 1954«. The beds above the Carboniferous Limestone in north-west County Clare. Quart. J. geol. Soc. Lond. 109, 259-83, pi. 11, 12. 19546. The Carboniferous rocks of Foynes Island, Co. Limerick, Ireland. Geol. Mag. 91, 153-60. 1959. The palaeogeography of Homoceras times in western Europe. Bull. Soc. beige Geol. Pal. Hydr. 68, 134-50, pi. 1. and moore, e. w. j. 1959. Goniatites striatus and related forms from the Visean of Ireland. Palaeontology, 1, 384-96, pi. 64—69. holzapfel, e. 1889. Die Cephalopoden-fiihrenden Kalke des unteren Carbon von Erdbach-Breitscheid bei Herborn. Paldont. Abh., n.f., Band 1 (der ganzen Reihe Bd. 5), Heft 1, 3-77, pi. 1-8. Hudson, r. g. s. 1926. On the rhythmic succession of the Yoredale Series in Wensleydale. Proc. Yorks, geol. Soc. 20, 125-35. — — ■ 1939. The Millstone Grit succession of the Simonseat anticline, Yorkshire. Ibid. 23, 319^19. 1941. The Mirk Fell Beds (Namurian, E2) of Tan Hill, Yorkshire. Ibid. 24, 259-89. — - — - 1944. The faunal succession in the Ct. nitidus zone in the mid-Pennines. Proc. Leeds phil. lit. Soc. 4, 233-42. 1945. The goniatite zones of the Namurian. Geol. Mag. 82, 1-9. 1946. The Namurian goniatites Cravenoceratoides bisati Hudson and Cravenoceratoides lirifer n. sp. Proc. Yorks, geol. Soc. 25, 375-86, pi. 21, 21a. and cotton, g. 1943. The Namurian of Alport Dale, Derbyshire. Ibid. 25, 142-73. — — 1945a. The Lower Carboniferous in a boring at Alport, Derbyshire. Ibid. 25, 254-329. — - 19456. The Carboniferous rocks of the Edale anticline, Derbyshire. Quart. J. geol. Soc. Lond. 101, 1-36, pi. 1. and Mitchell, g. h. 1937. The Carboniferous geology of the Skipton anticline. Summ. Progr. geol. Surv., Lond., for 1935, (2), 1-45. and Stubblefield, c. J. 1945. Discussion on Dunham, K. C. and Stubblefield, C. J. 1944. The stratigraphy, structure and mineralization of the Greenhow mining area, Yorkshire. Quart. J. geol. Soc. Lond. 101, 135-7. hull, e. 1878. Physical geology and geography of Ireland. London. 1881. The coalfields of Great Britain. 4th ed. London. hyatt, a. 1884. Genera of fossil Cephalopoda. Proc. Boston Soc. nat. Hist. 22, 273-338. Ireland, Dail. 1921. Memoir. Commission of inquiry into the resources and industries of Ireland (Connacht Coalfield, 127—44). Dublin. jackson, J. w. 1927a. The succession below the Kinder Scout Grit in north Derbyshire. J. Manchr. geol. Ass. 1, 15-32, pi. 1. 19276. Geology of the Rossendale Anticline. Explanation of Sheet 76. Mem. geol. Surv. U.K. 1927c. New Carboniferous lamellibranchs and notes on other forms. Mem. Manchr. lit. phil. Soc. 71, 93-122, pi. 1-3. kane, Sir r. 1845. Industrial Resources of Ireland. 2nd ed. Dublin. king, w. b. r. 1914. A new trilobite from the Millstone Grit of N. Yorkshire. Geol. Mag., Dec. 6, 1, 390-4, pi. 32. leidy, j. 1856. Indications of two new genera of extinct fishes. Proc. Acad. nat. Sci. Philad. 7, 414. m‘coy, f. 1844. A synopsis of the characters of the Carboniferous Limestone fossils of Ireland. Dublin. 1851. Descriptions of some new Mountain Limestone fossils. Ann. Mag. nat. Hist., Ser. 2, 7, 167-75, pi. 1. meek, f. b. 1874. New genus Euchondria Meek. Amer. J. Sci. 7, 445, 488-9. miller, a. k. and furnish, w. m. 1940. Studies of Carboniferous Ammonoids, Pts. 1-4. J. Paleont. 14, 356-77, pi. 45-49. 1958. The goniatite genus Anthracoceras. Ibid. 32, 684—6. and youngquist, w. 1948. The cephalopod fauna of the Mississippian Barnett formation of central Texas. Ibid. 22, 649-71, pi. 94-100. and nielsen, m. l. 1952. Mississippian cephalopods from western Utah. Ibid. 26, 148-61, pi. 25, 26. 442 PALAEONTOLOGY, VOLUME 5 moore, e. w. J. 1936. The Bowland Shales from Pendle to Dinckley. J. Manchr. geol. Ass. 1 (3), 167-92, pi. 1-3. 1939. The goniatite genus Dimorphoceras and its development in the British Carboniferous. Proc. Yorks, geol. Soc. 24, 103-28, pi. 15. 1946. The Carboniferous goniatite genera Girtyoceras and Eumorphoceras. Ibid. 25, 387-445, pi. 22-27. — — 1950. The genus Sudeticeras and its distribution in Lancashire and Yorkshire. J. Manchr. geol. Ass. 2(1), 31-50, pi. 1-3. — — 1958. Dimorphoceratidae from the Upper Visean Shales of Co. Leitrim, Eire. Proc. Yorks, geol. Soc. 31, 219-26, pi. 14. moseley, f. 1954. The Namurian of the Lancaster Fells. Quart. J. geol. Soc. Load. 109 (for 1953), 423-54, pi. 22. nevill, w. e. 1956. The Millstone Grit and Lower Coal Measures of the Leinster Coalfield. (Appendix on the non-marine fauna by R. M. C. Eagar.) Proc. R. Irish Acad. 58 (B), 1-16, pi. 1-5. 1957. The geology of the Summerhill Basin, Co. Meath, Ireland. Ibid. 293-303, pi. 22. newberry, j. s. and worthen, a. h. 1870. Descriptions of fossil vertebrates. Geol. Surv. Illinois , 4, 347-71, pi. 1-4. Newell, n. d. 1937. Late Palaeozoic pelecypods: Pectinacea. Rep. geol. Surv. Kansas, 10. noyer, G. v. du. 1863. On the bituminous coal of the Arigna district, Counties of Roscommon and Leitrim. Geol. Mag., 81-92, pi. 5, 6. obruchev, d. 1953. A study of Karpinsky’s work on the Edestidae. Trans. Inst . paleozool. Acad. Sci. U.R.S.S. 45, 1-85, pi. 1-6 (in Russian). padget, p. 1953. The stratigraphy of Cuilcagh, Ireland. Geol. Mag. 90, 17-24. Parkinson, d. 1926. The faunal succession in the Carboniferous Limestone and Bowland Shales at Clitheroe and Pendle Hill. Quart. J. geol. Soc. Lond. 87, 188-244, pi. 12-17. ■ 1936. The Carboniferous succession in the Slaidburn district, Yorkshire. Ibid. 92, 294-331, pi. 24-26. patteisky, k. 1929. Die Geologic und Fossilfiihrung der Mahrisch-Schlesischen Dachschiefer und Grauwackenformation. Troppau. 1933. Faunen- und Floren-Folge im ostsudetischen Karbon. Berg.- u. hiittenm. Jb. 2, 41-52, pi. 2. 1936. Die obercarbonischen Goniatiten der Hultschiner und Ostrauer Schichten. Neues Jb. Min. Geol. Palaont. 76, 1-30, pi. 1. Phillips, J. 1836. Illustrations of the geology of Yorkshire. Pt. 2, The mountain Limestone district. London. pickel, w. 1937. Stratigraphie und Sedimentanalyse des Kulms an der Edertalsperre. Z. dtsch. geol. Ges. 89, 233-85, pi. 11-14. ramsbottom, w. h. c. 1959. Distinctions between the Carboniferous lamellibranch genera Canevella, Posidonia and Posidoniella. Palaeontology, 1, 405-6, pi. 71, figs. 8-14. reed, f. r. c. 1942. Some new Carboniferous trilobites. Ann. Mag. nat. Hist., 11th ser., 9, 649-72, pi. 8-11. roemer, f. a. 1854. Beitrage zur geologischen Kenntnis des nordwestlichen Harzgebirges. Palaeonto- graphica, 3 (1), 1-67, pi. 1-10. ruprecht, l. 1937. Die Biostratigraphie des obersten Kulm im Sauerlande. Jb.preuss. geol. Landesanst. 57, 238-83, pi. 9, 10. ruzhencev, v. e. 1947. Representatives of the family Dimorphoceratidae Hyatt in the Carboniferous deposits of the Urals. C.R. Acad. Sci. U.R.S.S. 56, 521-24 (in Russian). scanlon, J. e. 1953. The Carboniferous rocks near Garristoun, Co. Dublin, and in the adjacent part of Co. Meath. Sci. Proc. R. Dublin Soc. 26, 145-57, pi. 12. schmidt, h. 1925. Die carbonischen Goniatiten Deutschlands. Jb. preuss. geol. Landesanst., 45, 489-609, pi. 19-26. 1934. Cephalopodenfaunen des alteren Namur aus der Umgegend von Arnsberg in Westfalen. Ibid. 54, 440-61. schwarzbach, m. 1936. Die Trilobiten im Oberkarbon Oberschlesiens. Ibid. 56, 422-43. smyth, l. b. 1950. The Carboniferous System in N. Co. Dublin. Quart. J. geol. Soc. Lond. 105, 295-326, pi. 17-19. P. J. YATES: NAMURIAN OF SLIEVE ANIERIN 443 spath, L. F. 1934. A catalogue of the fossil Cephalopoda in the British Museum ( Natural History). Pt. 4 The Ammonoidea of the Trias. Stephens, J. v. et al. 1942. The faunal divisions of the Millstone Grit Series of Rombalds Moor and neighbourhood. Proc. Yorks, geol. Soc. 24, 344-72, pi. 31. 1953. Geology of the country between Bradford and Skipton (Sheet 69). Mem. geol. Surv. U.K. susta, v. 1928. Stratigraphic des Ostrau-Karviner Steinkohlenreviers im Lichte der Palaontologie. Der Kohlenbergbau des Ostrau-Karviner Steinkohlenreviers, 1, 381-484, 75 pi. tonks, l. h. 1925. The Millstone Grit and Yoredale rocks of Nidderdale. Proc. Yorks, geol. Soc. 20, 226-56, pi. 19. weigelt, J. 1922. Die Bedeutung der Jugendformen karbonischer Posidonomyen fur ihre Systematik. Palaeontographica , 64, 43-130, pi. 22-31. wolterstorff, h. 1899. Das Untercarbon von Magdeburg-Neustadt und seine Fauna. Jb.preuss. geol. Landesanst. 19, 3-64, pi. 2, 3. woodward, a. s. 1917. On a new species of Edestus from the Upper Carboniferous of Yorkshire. Quart. J. geol. Soc. Loud. 72, (for 1916) 1-6, pi. 1. yates, p. j. 1961. New Namurian goniatites of the genus Eumorphoceras. Palaeontology , 4, 54-58, pi. 6. youngquist, w. 1949. The fauna of the White Pine Shale of Nevada. J. Paleont. 23, 276-305, pi. 56-64. PATRICIA J. YATES Department of Geology, Imperial College, London, S.W. 7 Manuscript received 22 November 1961 FURTHER STUDIES ON MICRO-ORGANISMS AND THE PRESENCE OF SYNGENETIC PYRITE by LEONARD G. LOVE Abstract. Various microscopic pyrite forms are described from Lower Jurassic and Carboniferous argillaceous rocks and it is confirmed that solution of the pyrite reveals abundant microfossils of a limited range of morpho- logical variety which are described and figured. Two groups are distinguished, one showing clear association with plant material and the other with animal remains. Of the latter, occurrences of later geological and Recent ages are briefly noted and figured. Both forms were probably of a saprophytic nature and are thought to have been involved in the production of hydrogen sulphide and, consequently, the precipitation of the iron sulphide with which they are now found. The environment of this activity is discussed with particular reference to the Liassic deposits studied. No stratigraphic distinction is found for the microfossils within the inclusive period from Lower Carboniferous to Lower Jurassic. This paper presents the results of research in continuation of that published earlier by the author (Love 1957). While elaborating the phenomena then described, it demon- strates their extensive occurrence in other strata and throws some light on the many problems previously left unsolved. These arose from the original demonstration that microscopic pyrite grains of generally characteristic sizes and shapes, occurring in various shales and a bituminous limestone of the Scottish Lower Carboniferous sequence, exclusively embodied small objects regarded as microfossils of a hitherto un- known type. On the basis of this association, these bodies were held to be the remains of organisms which themselves were producers of hydrogen sulphide and became filled and coated with iron sulphide as a result. The smaller of the two types of micro-fossil designated, Pyritosphaera bar bar ia Love 1957, was yielded by small uncompressed spherical pyrite grains with a characteristic framboidal surface texture. In size and form these resembled the pyrite grains already noted in the geological literature by many authors (see Love 1957, pp. 429, 437) from many other beds of dark shale, coal, and indeed certain other rocks more generally associated with their yield of metal ores. At the time, however, the investigation was not carried into these fields. The larger supposed micro-organism, Pyritella polygonalis Love 1957, appeared also to have counterparts in such rocks. The present paper is concerned with furthering knowledge of the palaeontology and ecology of these organisms. Attention is mainly confined to the Rhaetic and Lias of Britain and some supporting studies on Carboniferous and more recent deposits. The Rhaetic and Liassic rocks were chosen as providing accessible and well-known sequences of suitable argillaceous rocks whose general conditions of deposition have already been studied in detail by other authors. It had already been demonstrated (Love and Zimmerman 1961) that studies of sul- phide spheres might with success be applied to such ancient rocks as the Lower Proterozoic Mount Isa Shales of Queensland, Australia, in suggesting the origin of the vast quantities of primary sulphide present there. The slightly metamorphosed condition of the rock, however, added difficulty to the work attempted and precluded much additional under- standing being gained of the phenomena observed. In the case of the Permian Kupfer- [ Palaeontology, Vol. 5, Part 3, 1962, pp. 444-59, pis. 63-64.] L. G. LOVE: MICRO-ORGANISMS AND SYNGENETIC PYRITE 445 schiefer of Germany, the classic ground of dispute over the origin of pyrite spheres in dark shale, it has been found possible to apply the findings of the present paper and to demonstrate much the same range of micro-organisms in a very similar environment; being concerned with ideas on ore genesis this is published elsewhere (Love 1962). In the present work the small particle size of some of the organic material imposed a limit to the usefulness of the ordinary microscope, and it is likely that with improved methods and the use of more elaborate equipment much more information including chemical data will become available against which many of the conclusions so far reached may be tested. The subject-matter is of wide significance in the formation of an important type of sedimentary rock. Full acknowledgement to the work of others is made in the text. Thanks are also due to all those who at various times have provided specimens for special study. The research was carried out in the Department of Geology of the University of Sheffield. LOWER JURASSIC STUDIES Source of material. The Westbury Beds provided the Rhaetic specimens and were principally collected from the Garden Cliff section near Westbury on Severn, Gloucester- shire, and from St. Mary’s Well Bay, Glamorganshire. Lower Lias rocks were taken from St. Mary’s Well Bay and the Yorkshire coast at Robin Hood’s Bay and near Redcar; Middle Lias specimens from the Yorkshire coast south-east of Staithes; and the Upper Lias succession of Grey Shales, Jet Rock, Alum Shale Series, and Peak Shales from shore sections around Whitby. Confirmatory specimens from boreholes near Whitby were kindly provided by Dr. J. E. Hemingway. The South Wales and Gloucestershire sections of Rhaetic and Lias are described in detail by Richardson (1905) while the Lias of the Yorkshire coast is described by Hemingway (1934) in general terms and some of the sections in greater detail by How- arth (1955). All these authors paid close attention to faunas but only Hemingway recorded details of the finer microflora of these beds, referring (op. cit., p. 257) to the presence of spore cases, microspores and macrospores in the Alum Shales and Jet Rock Series. Although few preparations to reveal this microflora have been carried out by the present author (necessarily involving a different process from that described below), enough has been seen to show much material present in most of the beds studied, and Mr. D. Wall (personal communication) confirms the presence of spores, algae, and hystrichospheres in many of the Liassic strata. Remarkably consistent results were obtained from the Rhaetic and Liassic rocks, from which the normal dark to grey, fine or only slightly silty shale and mudstone lithologies were analysed. In subsequent sections, therefore, it has not been found necessary to specify the particular horizons from which described material was obtained. Description of the pyrite. The Jet Rock is typical of much of the Liassic and Rhaetic strata in the occurrence of pyrite, which X-ray examination showed to be the only sulphide present. There are pyritic replacements of delicate mollusc shells and thin coatings around concretions (Hemingway, in Hallimond et al. 1950, p. 60), as well as finely disseminated pyrite in the forms with which this paper is concerned, and revealed only by the microscope (PI. 63, fig. 15). In other beds, such as the Alum Shales, larger irregular masses of pyrite occur. In nearly all the shales encountered, however, from 446 PALAEONTOLOGY, VOLUME 5 highly to only slightly bituminous, or even slightly silty, the finely disseminated pyrite is abundantly present and it is clearly an important and widespread component of the rock. Although predominant as small single or compound rounded spheres, six types of occurrence are described. Some of these intergrade and precision in distinguishing them is not really possible. The significance of the forms will appear in a later section. Pyrite type (a). Small grains up to 2-3 p in size varying in shape between angular and spherical. The latter, at the upper end of the size range, may well intergrade with the material of type ( b ). In the case of the smallest grains even determination of their shape becomes difficult. All are scattered throughout the shale as may be seen either from thin sections or from mounts of a poorly disaggregated shale in which thin clots of material remain in their original state. The proportion of type (a) is undoubtedly much increased at the expense of other types, and also of concretions, nodules, and shell replacement material after crushing of the rock. The pyrite seen on spores is sometimes in tiny grains but due to their small size a relationship to the spore tissue can seldom be determined. Pyrite type (b). Simple spheres ranging in size from 2-3 p up to 15 p or 20 p. Often the framboidal texture so often associated with this form of pyrite can be observed in which the surface of the spheres is composed of numerous tiny grains or crystals of sulphide. This is a detail only clearly seen in reflected illumination from above a polished surface (see Love 1957, pi. 33, fig. 2). Pyrite type (c). Multiglobular bodies of more complex outline. They show rounded bulges each of the same size range and texture as the individual spheres (type ( b )) as if compounded of them. In individual isolated multiglobular bodies tested, the compon- ent parts are not easily prised apart with a fine needle, and certainly not without ruptur- ing the structure. Their outlines are those of the bodies in PI. 63, figs. 10, 12. Some of the compound bodies attain a nearly uniform equatorial outline, and only solution will reveal their nature. At the other extreme, however, some are difficult to distinguish from unconnected but touching single spheres. From the nature of the organisms re- leased by solution of the sulphide it is unlikely that many of the instances in which spheres are seen just touching in thin sections and rather dense mounts of isolated material do in fact represent actual organic connexion rather than chance juxtaposition. It is certainly not felt safe to attribute to organic causes all the forms such as chains, rings, and even budding, that might be surmised purely from study of sections of the rock. The surface texture of the multiglobular pyrite bodies, and also the single spheres at the larger end of their size range, may be rougher when seen in outline, and have a coarser surface texture of large pyrite grains or crystals, than is normal in the framboidal texture. They tend therefore to be reminiscent of the Kiesklumpchen (verezte Bakterien EXPLANATION OF PLATE 63 All figs., Liassic material. Figs. 1-13. Micro-fossils released from pyrite grains in shales. 1, 2, 5-8, 10-13, X 2,000 approx. 3, 9, X 1,000. 4, X 3,000. Fig. 14. Spore or pollen grains with pyrite coating, X 500. Fig. 15. Thin section of P. spinatum zone shale normal to bedding in ordinary transmitted light; black grains are pyrite, X 250 approx. Fig. 1 6. Plant spore with vesicle and corebody, cleared of pyrite, X 1 ,600. Palaeontology, Vol. 5 PLATE 63 LOVE, Micro-organisms and Syngenetic Pyrite L. G. LOVE: MICRO-ORGANISMS AND SYNGENETIC PYRITE 447 Typ II) (mineralized bacteria) which Neuhaus (1940, p. 319, fig. 6) described from the Kupferschiefer. The material now described shows graduations between larger and smaller surface grains, possibly corresponding to some extent with the size of the bodies bearing them. Possibly, therefore, some of the Kieskliimpchen-types are a particularly coarse extreme of the Kieskiigelchen, Neuhaus’s normal framboidal sphere. When seen disaggregated from the rock, a number of multiglobular pyrite grains especially from the more bituminous shales may show shreds of organic tissue attached. It is very probable that from a highly compressed shale containing fragments of plant tissue of many kinds such material may remain adhering to a pyrite grain by chance, so apart from those cases which may appear significant from the prepared oxidation mounts, such occurrences are not pressed as sources of information. Pyrite type ( d ). Undoubted pyrite on recognizable spores and pollen grains and on other bodies of a similar general shape and material. These bodies (PI. 63, fig. 14), usually from 30 /x to 100 /x in size, and clearly exceptional in character, may show single isolated grains or spheres of pyrite (types (a) and ( b )) or a mass of spheres to the extent of a complete cover of pyrite. The coarse Kiesklumpchen texture of pyrite may be developed in partially covered bodies, perhaps explaining the nature of others of similar texture but completely pyritic. It is difficult to demonstrate by physical means the relationship of the pyrite to the spore or pollen grains. In some cases it is easily detached and leaves no mark or damage; in others an angular depression may be left; and again in others the pyrite may appear to be united with the wall material, for manipulation with a needle only ruptures the whole specimen. In some of the shales studied spores, pollen grains, and similar bodies with adherent pyrite form a substantial part of that aspect of the microflora, an observation which Mr. D. Wall confirms. They are often individually of a sufficiently high aggregate specific gravity to appear in the heavy fraction of a bromoform separation. So too are many aggregrates of pyrite from the shale containing fragments of organic tissue, and gen- erally of unidentifiable origin, but to which the general description of pyrite as for spores and pollen is fully applicable. Pyrite type ( e ). Larger pyrite ‘microberries’ up to 120 p in size. These are found when the finer fraction from a less intensely crushed rock is examined beneath a high-power binocular microscope. The descriptive name given by Macfadyen (in Love 1957, p. 437) is retained. They have a generally rounded shape and are clearly composed of large numbers of smaller spheres, 20-50 /x in size, which give the characteristic appearance. The microberry as a whole is not truly framboidal, but the smaller spheres are. On crushing, the berry breaks down readily into the separate smaller spheres, and these in turn break down into material between 0-5 p and 5 p in size, but of this the larger parts are found to be aggregrate, as yet uncrushed, of the 0-5-1 -5 p grains which are there- fore basic to the whole microberry. In one specimen provided by Dr. Macfadyen calcite cement held the intermediate spheres together in the microberry; they became separated after effervescence in dilute hydrochloric acid but the intermediate spheres themselves did not react with the acid. Pyrite type (/). Foraminiferids with pyrite infillings. The author’s attention was first drawn to the occurrence of such specimens in the Lias by Dr. C. G. Adams. Through the moistened calcareous tests of various Lagenids pyrite could clearly be seen (PI. 64, 448 PALAEONTOLOGY, VOLUME! fig. 7) and on solution of the shells of such specimens accumulations of pyrite resembling the microberries were released from the chambers, whose internal shape they sometimes retained. Experimental methods. The observations recorded in this paper concerning the bodies from the pyrite were obtained from two lines of investigation. One consisted of the chemical treatment of small bulk samples of pyrite concentrated from a rock, and pro- vided adequate quantities of the final product for proper washing and preparation as permanent mounts on microscope slides. Comparison with a mounted sample of the untreated pyrite then allowed an inference to be made of the relationship between the pyrite and the cleared bodies. For the bulk process, the laboratory methods used were essentially those described by Love (1957, p. 431) and in greater detail by Love and Zimmerman (1961, pp. 883-4). Mechanical disaggregration of the rock sample by grinding was followed by separation of the heavy mineral grains, predominantly pyrite, by centrifuging in bromoform (s.g. 4-9). Unless it was to be examined for material which might be partly calcitic, the heavy residue was then treated for some days with warm hydrofluoric acid to remove traces of adhering light minerals, and when so cleaned it was oxidized in warm or hot concentrated nitric acid or other reagent. After removal of the acid and after several washings of water, the few remaining drops of suspension yielded small micro-organisms, as described below, in proportion to the original yield of rounded pyrite grains. The chemical treatment and the preparation of slides was carried out under strict precautions to avoid contamination. Though useful, bulk solution is not usually a rigorous enough method to determine some of the re- lationships and in many instances it was found necessary to carry out the process in such a way as to see it actually happening under the microscope. Virtually continuous observation of the solution of the pyrite was made possible by use of the special cell, only developed late in the course of earlier work by Love (1957, p. 432) and subsequently described in detail by Love and Zimmerman (1961, pp. 884-5). It was possible to confirm that each form of micro-organism described could in fact be obtained in that condition from a particular grain of pyrite from the sediment. An inherent difficulty in this method, however, is that it is frequently impossible to preserve the material revealed and to make a permanent mount. To achieve this it is necessary, without losing a specimen perhaps only a few microns in size, to remove the excess reagent around it and to irrigate the chamber with water to prevent later crystallization of salts produced in the reaction. This direct observation method obviates the need for elaborate statistical support for such assertions as are made, as was attempted in earlier work (Love 1957, pp. 431-2) and the method is essential if only a limited amount of material is available, for example part of the pyritic content of a single foraminiferid. In the bulk method, large numbers of foraminiferids would be needed for a single preparation. It is also possible to observe the actual position of the sulphide, for instance whether it occurs superficially or within organic material, and to watch for evidence of other soluble minerals such as calcite originally accompanying the pyrite. Description of the micro-organisms released from the pyrite. The micro-organisms re- maining after the removal of the pyrite are varied in appearance but lie in a limited number of groups, some of which are clearly interrelated. L. G. LOVE: MICRO-ORGANISMS AND SYNGENETIC PYRITE 449 Group 1. Spherical bodies (PI. 63, figs. 1, 2) 5-20 p in diameter occurring abundantly, resembling Pyritosphaera barbaria Love 1957 (p. 433). They appear to be composed of a tightly packed mass of small cells, 0-5-1 p, each one of which can be seen during solu- tion to contain a single pyrite crystal. Occasionally, however, the aggregate of cells is looser and often the larger bodies in the size range about 20 p show this. Polished sec- tions of pyrite spheres in the rock confirm a uniform internal structure. The very thin skin of transparent tissue around the individual pyrite grains does not appear to affect their reflecting power and has not been observed in the sections. Group 2. Bodies as described above ( P . barbaria) with a partial or complete thin outer envelope of smoother tissue. If complete (PI. 63, fig. 4) in the polar view it hardly ob- scures the characteristic appearance of the microspinose body, but this is no longer clear equatorially. Careful focusing of the microscope at high magnification often makes it possible to demonstrate the complete continuity of the sac below and above the core body. Other bodies (PI. 63, fig. 2) only bear a shred of such material. The microspinose core body may be considerably smaller than the outer sac (PI. 63, fig. 6) and less charac- teristically developed, in many cases appearing as a less perfectly formed mass of micro- granular character (PI. 63, fig. 5). Masses like this, if found isolated, could be included in Group 1 above. Only one core body occurs within any one sac; but the latter often occur in tightly packed compound groups, up to six together being common as well as more complex formations. Here not all the sacs necessarily contain core bodies. The tissue of the sacs is described below (Group 3) and a similar outer wall to the group, as described there, is present here. Group 3. Hollow sacs whose general appearance is like that described for the sacs with core bodies. Less common, they are transparent to translucent and of a variable smooth to rough surface appearance. In photographs at an equatorial level of focus the walls appear as a thin line or as a rougher, thicker layer of material. The number of cells in the group may again be from one (PI. 63, fig. 8) to many (PI. 63, figs. 10 and 12). The outer wall as a whole often appears to be stronger and thicker than the apparently common walls separating individual sacs. Furthermore, these inner walls may not be complete and some instances giving a distinct appearance of cells in division have been noticed. This may best be described as a ‘dumb-bell’ shape, with a constriction but no actual wall between the cells. Sometimes such adjacent cells may be more or less equal in size but often one is smaller. Both simple and compound sac forms have been observed while becoming cleared of pyrite. The former come from single spheres. If no well-formed core body is present the pyrite inside the sac may, in its later stages of solution, be irregular (PI. 63, fig. 13) but is sometimes idiomorphic, though not often appearing to have impressed this shape on the sac from within. Sometimes breakdown into small dark grains can be seen. These may leave either no remnant or microgranular organic material (PI. 63, fig. 5); it must be stressed, however, that with the empty cells it is in most cases very difficult to decide whether absolutely no grains of core material are present, as distinct from any slight granularity or roughness of the wall. The compound sac forms are released from multi- globular pyrite grains of similar outline or from apparently single spheres, the coarseness of whose outer pyrite may obscure the detailed shape. These multi-globular pyrite bodies 450 PALAEONTOLOGY, VOLUME 5 and the sac bodies from them appear uncompressed and usually are more or less symmetrical and free from attachment to any other material. Group 4. Spores and pollen grains, recognizable at least by their general shape, showing, after solution of sulphide, patterns of irregularly developed high-relief ring markings on the surface, observed to correspond with the position of the sulphide. (This is discussed on p. 452.) In some particularly clear specimens examination at high magnification has revealed that the structures, which vary from circular to polygonal, and measure 3-10 p are vesicle-like developments apparently within the surface layers of the exine, but often this is difficult to decide. Some markings merely appear to be the result of other com- ponents of the shale, often pyrite as spheres, pressing in during lithification. The vesicles originally contain pyrite and in some instances it has been possible to witness its disappearance from them during solution. In some of these vesicles microspinose spheres are found (PI. 63, fig. 16) identical with the core bodies of the isolated sac- bodies, single and compound, described in Group 3 above. Other fragmental organic tissue, generally darker than the spores and of unknown origin, often also reveals round to hexagonal pits or blisters, lighter in appearance, some containing microspinose or roughly microgranular bodies. Group 5. Small clear granules or particles 0-5-2 p in size, yielded from the pyrite in- fillings of foraminiferids and from microberries (PI. 64, fig. 8). The observation method has been used exclusively. There is no clear evidence of the presence within the pyrite of any organic structure larger than about 2 p, which is the upper limit of the grains into which the material can be broken, and which form the profile of the intermediate round aggregates that make up the microberry as a whole. Very gentle or very rapid solution sometimes leaves them in large spherical groups, but these appear as loose clusters only and the particles readily drift apart, subject to the movement of liquid and air bubbles around them. Close observation in this freely moving condition is difficult but freshly prepared specimens appear to be small clear round cells, of a rather high refractive index and having no effect upon plane polarized light. Some are perhaps seen in a state of division but most are single, rounded to slightly elongated, and featureless. Group 6. Many of the smallest grains of pyrite (type (a)) in the concentrates dissolve to leave small cell-bodies behind such as are described above, although others dissolve without leaving any trace as would be expected if they are derived from shell and nodule EXPLANATION OF PLATE 64 Figs. 1-6, Carboniferous; 7, 8, Liassic; 9, Eocene; 10, Recent material. Figs. 1, 3. Bodies of P. polygonalis type, X 1,400. Fig. 2. Micro-fossils released from pyrite grain in shale, X 2,000. Figs. 4, 5. Parts of surfaces of spore material showing vesicular formations and a core body. 4, X 2,000. 5, X 2,500. Fig. 6. Partly cleared intermediate sphere from pyrite microberry, Scremerston Coal Group, X 3,000. Fig. 7. Pyrite-infilled foraminiferid, transmitted light, X 30. Fig. 8. Dispersed cells from solution of pyrite infilling of a foraminiferid, X 2,000. Fig. 9. Cells from solution of a pyrite microberry, probably internal cast of a diatom, X 2,000. Fig. 10. Cells from solution of pyrite infilling of a foraminiferid, partly or completely cleared, X 2,000. Palaeontology, Vol. 5 PLATE 64 LOVE, Micro-organisms and Syngenetic Pyrite L. G. LOVE: MICRO-ORGANISMS AND SYNGENETIC PYRITE 451 pyrite. Similar material has been observed in most bulk-prepared samples among the other organic residues but it is so small that it is not easily studied or recorded except when specially prepared. On some spores and other tissues tiny grains of pyrite have left such small cells but no particular relationship of either the pyrite or the small cells to the host material can be determined. INTERPRETATION OF THE MORPHOLOGY OF THE MICRO-ORGANISMS Within the variety of material released from the pyrite, the close relationships which clearly exist must now be discussed. It is convenient to consider Groups 1-4 of organic material together first, and Groups 5-6 afterwards, bringing in, where relevant, evidence obtained from sources other than the Liassic rocks. Micro-fossils , Groups 1-4. Considering the material from isolated simple and compound pyrite spheres (pyrite types ( b ) and (c)) all gradations are to be found, firstly, from the single sac to the complex group and, secondly, concerning organic material within the sac, from the rough accumulation of small grains to the well-formed microspinose body of the Pyritosphaera barbaria type, apparently composed of similar grains. From this it is likely that representatives of two developmental series are present, the one from single to compound sacs and the other of growth of core material within the sac, this being then secondary to the appearance of the sac. It is not thought that the cores represent the residue of normal cell contents. The balance of evidence is against the original occurrence in the shale of the Pyritosphaera barbaria bodies free of external sacs, for even if observed solution of some spheres reveals no sacs or only shreds of attached material the grinding involved in the original preparation could have stripped off and destroyed them. Less intensely ground material showed more outer sacs. In transmitted light some isolated pyrite spheres show the presence of a very thin translucent skin at the periphery, external to the sulphide but not affecting the reflecting powers of this mineral on the upper surface of the sphere. Also suggesting the outer position of the sac, the appropriate Liassic sphere when its solution is watched does not usually show the loss of pyrite external to the sac. The tendency for the core body, when fairly well developed, to show attachment to one part of the sac wall, in an off-centre position (PL 63, fig. 6), is supported by the way in which many examples of P. barbaria have a residual polar cap or tail of attached material. It is difficult not to regard as further manifestations of the same general phenomenon of sacs with core bodies the vesicles on Liassic spores and pollen which often contain P. barbaria. These formations have been shown to be equally associated with pyrite. In fact, in view of the discussion below, it may well be that the isolated saccate forms first originated in association with some plant tissue of which no other trace is now preserved. Further interpretation and explanation will perhaps in due course be made since this aspect of the work also falls within the scope of current research and publication on the microbiological destruction of plant remains by the author’s colleagues, Prof. L. R. Moore, Dr. R. Neves, and Dr. H. J. Sullivan, who are concerned with the effects of what appear to be rather similar ring or vesicle structures (present author’s termin- ology) as one of the factors in the degradation of Carboniferous plants, spores, and pollen. The occurrence in some of these structures of core bodies recognizable as P. C 674 Gg 452 PALAEONTOLOGY, VOLUME 5 barbaria strengthens the homology. Through the kind assistance of Dr. Neves the author was able to examine some typical Carboniferous rock material and observed that while normal maceration yielded abundant organic material of this type, when subjected to the methods described in the present paper a heavy fraction of the rock contained large partly or completely pyritized bodies whose characteristic size and shape showed them to be the same spores. Oxidation and solution of the pyrite revealed intensely vesicular exine previously not visible, with P. barbaria in some of the vesicles (PI. 64, figs. 4, 5), but in the specimens actually observed during solution, while it was confirmed that pyrite occurred within the blister-like vesicles, it could not be ascertained whether any organic cores remained. An attempt was made to determine the extent to which this pyritic condition in spores and pollen of both Carboniferous and Liassic age is to be associated with the particular secondary structure noted. The search was carried out on unoxidized material, disaggregated mechanically and by non-oxidizing mineral acids: bromine (Neves 1958, p. 3) was not used. Obviously the spores and pollen were not subjected to the usual cleaning and maceration to clarify their surface nature and observation in the detail required was therefore not easy, especially in Carboniferous material. Nothing was observed which demonstrated the existence of the vesicles in an unpyritized condition, and a close association with pyrite must be assumed. Various Carboniferous marine and non-marine shales and coals gave large yields of the same range of micro-organisms, with abundant P. barbaria, as described above. Free-standing compound saccate bodies were, however, distinctly more common in the Lower Jurassic rocks; obvious core bodies were rarer in the Rhaetic. The cause of these variations is not yet understood. In general chambers free of core bodies, whether isolated simple or compound bodies or on other tissue, are few in relation to the oc- currence of mature and poorly formed core bodies. Reconsideration of Pyritella polygonalis Love 1957. After study of the more complex forms of isolated saccate body described above it was found necessary to reconsider the species Pyritella polygonalis Love 1957 (p. 434). Although both are obtained from pyrite masses, any similarity between the type material of P. polygonalis and the free multisaccate bodies is not immediately apparent. A link was observed, however, through a series of preparations of rocks around the Upper Carboniferous Gastrioceras sub- crenatum marine band first made for Dr. R. M. C. Eagar (Love 1957, p. 440). Later, more exhaustive study of material obtained from pyrite revealed a range (e.g. PI. 64, fig. 2) similar to that obtained from the Liassic rocks and also multicellular material showing the characteristics of P. polygonalis. This form, in contrast to the diagnosis of the species (op. cit., p. 434), was not always as complete rounded masses but also oc- curred on fragments of other tissue such as spore exine in the manner of the ring structures already described. Core material occurred in some specimens of this type, some well-developed microspinose bodies of P. barbaria being included. On one speci- men illustrated (PI. 64, fig. 3), a margin of unaffected material surrounds the area of polygonal pattern. Further study of slides containing P. polygonalis from the Burdiehouse Limestone of Scotland (the type material) confirmed this observation (PI. 64, fig. 1) among material which was originally thought to be broken and fragmentary parts of larger bodies. The L. G. LOVE: MICRO-ORGANISMS AND SYNGENETIC PYRITE 453 regular form of the latter appears in all probability to be that of spores and some less- affected specimens of recognizable spores were in fact noted. The description of the cellular structure originally given, however, needs no amendment. So far, no core bodies have been found in this Burdiehouse Limestone material, although this discovery may yet be made. Their rarity here, and relative abundance elsewhere, is a factor not yet explained. The effect of these observations on the taxonomic status of P. poly- gonalis is discussed below. The particular feature of the polygonal shape to the vesicles, well shown in PI. 64,. fig. 1, and also on the spore material in PI. 64, fig. 4, appears to be secondary to the formation of the vesicle, derived from the idiomorphic crystal shape taken up by pyrite. The P. polygonalis material when pyritized has shown the remarkable Kieskliimpchen texture figured by Neuhaus (1940, p. 319, fig. 6). Here, in distinction from the small regular closely packed small pyrite crystals of the Kieskugelchen (pyrite spheres) the structure is of large, well-spaced angular crystals, up to 10 p across. In an earlier study of the type material of P. polygonalis , where it abundantly occurs, comparative camera lucida drawings (text-fig. 1) were made in reflected light of pyrite crystals from a typical Kieskliimpchen body, and of the polygonal vesicles in a P. polygonalis body from the same rock. That the pyrite outlines were all possible random cross-sections or equatorial outlines of the pyrite cube, octahedron, or pyritohedron makes it not surprising that later it was possible, on observing actual solution, to confirm that each pyrite crystal while becoming steadily smaller, at an early stage revealed the polygonal cells in whose centre, under a covering membrane, each one was situated. At the early stage the out- line of the chamber corresponded closely with the shape of the pyrite grain and the process often took place without rupture of the surface membrane. In another instance ultrasonic vibration failed to release pyrite from these bodies (or from normal frarn- boidal spheres), again demonstrating its non-superficial position on them. In contrast to these forms free of core bodies, the large pieces of spore material such as in PI. 64, figs. 4 and 5 showed a mixture of pyritic forms from large angular crystals to normal framboidal areas. The latter would be expected where core bodies are present and particularly when they are large. From some present-day data (see Love 1957, A B text-fig. 1. Comparative camera lucida drawings on same scale of a, Pyritella polygonalis, by transmitted light; b, sulphide grains on a Kieskliimpchen body, by reflected light. 454 PALAEONTOLOGY, VOLUME 5 p. 434) it is probable that the pyrite is secondary to some other sulphides and its crystal- lization may well be governed by physical factors in its immediate environment, to give either a single large crystal in a cell or a framboidal group. Why isolated sacs tend to be filled in the latter way while the vesicles in masses of vegetable tissue tend to the single polygonal form is not understood. Even where a single grain fills a free sac the polygonal shape does not often persist, perhaps because the material is less rigid. Conclusions concerning Groups 1-4. The two developmental series recognized for the isolated P. barbaria and sacs have now been extended to include the other material released from pyrite, some of it clearly secondary developments on plant debris. Of the two possible relationships between the two series the first is that the core material represents the fossilized remains of some investing parasitic or saprophytic micro- organism. In this case the sac is in the position of host. In principle such activity is common at present among lowly organisms, often with a preference for a particular host. Geologically, records are few; that noted by Kidston and Lang (1921) of supposed fungal investment of Devonian plant tissues shows no similarity to the forms under discussion here. In the present instance the host material could perhaps be small algae in the case of the simpler isolated sacs, while in the spores and pollen it could be a pre- existing secondary structure developed in the exine. The somewhat variable proportions of those forms described in different rocks is perhaps a factor in favour of the hypothesis, but the inclusion of saccate forms in which no investing material has conclusively been observed supports the contrary view. This other possibility is that the development of the sacs or vesicles is followed, in a distribution whose controls have not yet been recognized, by development of the core material to form the P. barbaria body, all as part of the life- cycle of a single organism. In either case, both the limited range of the organic forms involved and the environ- mental evidence to be discussed later imply that a special agency was employed in the pyritization. It may be noted here that over a period of some years the characteristic form of P. barbaria has never been obtained by the author from unweathered rock except by the solution of sulphide. The case has already been argued (Love and Zim- merman 1961, p. 891) that the formation of the sulphide ion was part of the life activity of the organisms rather than, after their death, being of external origin or essentially based on the decomposition of their tissue. Lurthermore, a distinct association with the degradation of plant material is thought to be shown, in contrast to the subject of the next section. On morphological grounds, however, the evidence is insufficient to allow a con- clusion to be reached on the nature of the organisms. It is not known even to what extent the fossilized material resembles in detail, in its microscopic appearance, its original form. Lurthermore, in the combined development series favoured here on the balance of evidence but not regarded as conclusively proved, it is not clear whether the core body has a final separate existence from its sac perhaps as some form of spore. It would not be valid to suppose that it does from the observations so far made, and this would then appear to preclude the individual cells of the core body from being the starting- points of new cycles, the origin of which remains obscure. The observation that the largest forms appear to have a rather looser structure than the others is not accompanied by any evidence of breaking up and dispersing, which would indeed seem impossible L. G. LOVE: MICRO-ORGANISMS AND SYNGENETIC PYRITE 455 in the undisturbed muds below the interface. Alternatively many lowly organisms form resting bodies under certain, usually unfavourable, conditions. Yet these barely seem appropriate as an explanation of the enormous abundance of the material in dark shales where the activity of the organisms has been so intense. Taxonomically, any grouping together of the microfossil forms described would involve considerable emendation of the existing genus Pyritosphaera and the species P. barbaria together with probable suppression of the genus Pyritella and inclusion of P. polygonal is in the emended species of P. barbaria. However, because of the complete lack of knowledge of the systematic position of the whole group, together with un- certainty about the various stages within it, and in view of the fact that current research on present-day sediments may ultimately indicate a solution to these problems, it is proposed that no taxonomic emendation should as yet be made. Micro-fossils, Groups 5-6. Two problems arise in the interpretation of the micro-fossil material obtained from pyritic foraminiferid infillings and microberries and also from widely scattered minute sulphide grains. One concerns distinction between the former group and the pyrite which yields P. barbaria and associated forms. The second problem involves, in more detail, the distinction between the individual granules of organic material from the pyrite of foraminiferids and microberries and the granular material of P. barbaria. Two factors help to differentiate the material in the first case. The saccate condition does not seem to exist for the 20-60 p intermediate spheres forming the pyrite masses in the foraminiferid tests and the microberries, although it commonly occurs with the spheres of the P. barbaria series. Furthermore, the core body of the latter, when well formed, remains unbroken after the treatment with acid, as if it were a discrete body, albeit a granular one. The opposite is the case for the spheres from the tests and microberries. It is tentatively concluded that different organisms are under consideration. This is supported by similar evidence from Carboniferous rocks. From crushed and ground marine shale from the Gastrioeeras cancellation horizon of the Axe Edge locality, Derbyshire, many unopened ostracods, mostly pyritized, and also goniatite spat smaller than 100 p, in size were picked out, together with microberries. From with- in some of the closed shells clusters of pyrite spheres were found lying completely out of direct contact with the rest of the rock material and appearing quite different from the smooth pyrite of the shell walls, from which, in the case of the goniatites, they were separated by a delicate tissue of wall membrane. Also perfect internal moulds of goniatite spat were found composed entirely of spheres and devoid of shell. Material of all these types, and also microberries, gave on solution great quantities of 0-5-1 -5 /x clear light granules (PI. 64, fig. 6), comparable with those described from the Lias. Flattened microberries from Eocene strata, provided by Dr. J. W. Murray, and giving a similar product on solution (PI. 64, fig. 9), were clearly the infilling of diatom tests of characteristic shape. Current work by Love and Murray demonstrates that pyrite in- fillings of recent foraminiferids, giving a similar product on solution (PI. 64, fig. 10) may develop soon after death at the mud-water interface whenever de-oxygenated condi- tions obtain. It is believed that identification of the micro-organisms involved here may be applicable to the Liassic and Carboniferous test-infillings, so consistent is the appearance of the pyrite and the organisms within it. The origin of the spherical 456 PALAEONTOLOGY, VOLUME 5 microberries, of whatever age, is not yet clear. If they are internal moulds of tests well filled with pyrite, no such tests were found in the rocks examined. It is possible, however, that if the test was originally of some soft organic tissue it may have completely decayed. The small individual granules of microfossil material (Group 6) obtained from isolated and unattached individual small pyrite grains could with equal likelihood have origina- ted as the partly developed cores in the P. barbaria series, or as crushed-down material from animal tests broken or otherwise removed even within the rock, or from micro- berries which may also have such a source. No means is at present known of recognizing their particular origin. It is clear that on the basis of the evidence of the pyrite material which must have developed within the tests of animals that a particular association with the degradation of animal material is attributable to the micro-fossil or present-day micro-organisms obtained from it. Again there must be some lowly organism involved and indeed the individual granules are of a size range appropriate for bacterial cocci. It might reason- ably be expected that differing micro-organisms would be involved in the decay of plant and animal material. It is not proposed at present to attempt to define the taxo- nomic position of these micro-organisms. It is likely that the granular organic remains found, after solution of pyrite, within the central chamber of specimens of Tasmanites from Liassic rocks may be assigned to this group. These large and distinctive bodies frequently contained small amounts of granular pyrite and could be picked out from the rock material for individual treatment. In all cases observed the pyrite contained organic material, and similar contents of Tasmanites appear to have been observed by Eisenack (1958) but no recognizable body of the P. barbaria type was found. ENVIRONMENT OF FORMATION OF THE SULPHIDE As a control on the validity of any conclusions concerning the micro-organisms drawn from geological or present-day evidence, the available geological information on the environment in which they flourished must be considered. Whatever their nature, they are very abundant, recognizable as simple pyrite spheres, and most characteristic of sedimentary rocks of the dark shale and sapropelic environment (Deans 1948, pp. 348-50). The value of applying such a simple criterion as the presence of micro-fossils to more complex rock groups has already been demonstrated (Love and Zimmerman 1961). Again, Deans has observed pyrite spheres in lesser quantity in the Northampton Sand Ironstone where Taylor (1949, p. 83) regards the limited pyrite formation as having been controlled by the temporary development of stagnancy. It may be necessary to modify the view put forward earlier by the author (Love 1957, p. 434) that the spheres and associated forms of pyrite and micro-organisms are as- sociated with bottom conditions entirely inimical to aerobic life. Bottom conditions in fact appear to have differed from rock to rock. In the case of the Pumpherston Shell Bed and Oil Shale of the Scottish Lower Carboniferous sequence evidence was put forward that no aerobic benthonic life existed in the area since only free swimming or floating organisms occur as fossils. In all the beds abundant pyrite spheres were found while the very fine lamination of the sediment was undisturbed. Related conditions are envisaged by Hemingway (in Hallimond et al. 1950, p. 68) L. G. LOVE: MICRO-ORGANISMS AND SYNGENETIC PYRITE 457 for the Jet Rock of the Yorkshire Lias. The beds are regarded as representing muds of slow accumulation under marine conditions in waters which at depth were deoxygenated and rich in H2S; as the sea extended at least to Germany the stillness must have been due to the bottom waters lying below the reach of major wave action in the open sea and therefore at some hundreds of feet in depth. The waters were fully marine, even if somewhat isolated from the main ocean. Similarity with the present state and recent history of the Black Sea is apparent. But it must be considered whether some property of very fine sediments rich in organic matter might enable a strong resistance to deformation to be attained sooner than is generally thought to occur. Unpublished evidence from the author’s collection of thin sections of Carboniferous shale sediments suggests that disturbance of a shale layer before deposition of the next may give small disarranged pellets with characters such as the cryptophyllite texture (Dunham in Eagar 1952, p. 358) already in their final re- lationship to the lamination of the pellet rather than that of the undisturbed shale. There is evidence from present-day organic-rich dark muds (J. W. Murray, personal communication) that even at the mud-water interface fine organic material binds up the clay sediment into a relative firmness. Furthermore, mucous-covered burrowers, such as Arenicola, which are normally prodigious ingesters of sediment, are strongly inhibited by the presence of much fine clay (Reid 1929). After deposition of the mud these factors might lead to an initially localized deoxygenation whose products would in turn lead to the beginning of the more generally foetid conditions by which other varieties of aerobic burrowers were also inhibited. It may not be necessary therefore to invoke very great depth, or alternatively, unusual climatic conditions such as the ab- sence of all but the gentlest of winds. Some climatic factors, however, may have induced other conditions favourable to the maintenance of long-standing stagnancy over a wide area. Hemingway regards the Jet Rock as the initial part of an Upper Lias cycle of sedi- ments produced by the shallowing of the deep sea basins which had originated under tectonic control. At the top of the Upper Lias cycle the sands of the Blea Wyke Series yield ‘frequent moulds of lamellibranchs, Pentacrinus debris and Serpula and are char- acterised by an abundance of worm tubes which ramify through the rock’ (op. cit., p. 69). This indicates intense scavenging activity able to remove all digestible organic material from the sediment, an activity which is normal in nature when no restraint is present but which must have been absent in the muds which ultimately gave the shales at the bottom of the sequence. These shales, however, show a steady gradation upwards (op. cit., pp. 68, 69), becoming less pyritic, less well laminated, less dark, and less bituminous; they were probably formed ‘in a marine environment which was becoming less stagnant and presumably less deep.’ In the Alum Shale Series microscopic pyrite is still found but occasional sideritic mudstones and calcareous concretions appear. Counts of grains in thin sections of typical specimens of the Hard Shales above the Alum Shales, and the Bituminous Shales below, show that the proportion of pyrite spheres and multispheres is about half the value in the Grey Shales, Jet Rock, and Jet Rock Shale. The Alum Shale Series is compared by Hemingway with the Grey Clay of the Black Sea, laid down in an environment appreciably shallower than that of the sapropelic muds and nearer the shore. There are two ways in which residual organic material may occur in a sediment, 458 PALAEONTOLOGY, VOLUME 5 giving a sapropel. Firstly, rapid deposition of organic material without much sediment at a rate in excess of that at which it can be utilized by mud-grubbing and burrowing organisms may cause some to be buried below their reach. Van Andel and Postma (1954) note that the maximum formation of sulphide in the Gulf of Paria at the present time is associated with such conditions, even where fairly strong currents renew the bottom waters. The same is recorded by Neeb (1943) from the East Indies. Secondly, toxicity in the sediment, due to the effects of stagnancy and lack of circulation, will inhibit or prevent at least aerobic organisms. This is due to the exhaustion of available oxygen for oxidation processes by organisms and the ensuing establishment of a chemically ‘reducing environment’. It is believed that in the case of the shales in the Upper Lias sequence rapid deposition was not the case: nevertheless the toxicity must have been confined to the well-laminated and undisturbed sediment, for undoubtedly a bottom surface-dwelling fauna was present, however peculiarly limited in variety. Besides free-swimming ammonites and pelagic micro-plankton living in the upper water, Inoceramus is prominent among thin-shelled lamellibranchs, but not common, although it increases in abundance in the Bituminous Shales ‘where some horizons become oyster beds’ (J. E. Hemingway, personal communication). In the Alum Shales Nuculana ovum is found. In the Rhaetic beds at Garden Cliff and the corresponding ones at Lavernock, Richardson (1905) has presented clear evidence of a bottom-dwelling fauna even from the black shales, including Pteria contorta, Pecten valoniensis, Protocardium rhaeticum, Gervillia praecursor, and Modiola minima. Hemingway (in Hallimond et al. 1950) regards this cycle, initiated by the Westbury Beds and passing up through the Sinemurian into the Lower Pliensbachian ironstone shales, and also the Middle Lias cycle culminating in the Cleveland Ironstone Series, to be less well developed than the Upper Lias cycle. Both Hemingway (op. cit., p. 70) and Raymond (1955, p. 16) regard the Rhaetic sea as having been shallower and more restricted in area than that depositing the Jet Rock. It is probable, then, that the zone of formation of the forms of pyrite described in this paper is within the mud rather than at the mud-water interface of the sediments giving the Lower Jurassic succession. Although a ‘sulphuretum’, a zone charged with hydrogen sulphide and inimical to aerobic life, may have been present this need not necessarily have lain in the bottom waters if oxygenation of these was sufficient to re- move that proportion of the toxic dissolved hydrogen sulphide which passed upwards out of the mud. Perhaps the limited fauna of the Jet Rock is indicative of the effect of the most extreme conditions of toxicity reached in this Series and undoubtedly conditions relaxed in the succeeding Bituminous Shales. Some parallel to this may perhaps be seen in the study by Eagar (1953, p. 341) of the non-marine lamellibranchs in shales of the Upper Carboniferous Lower Foot Mine succession of Goyt’s Moss, in which much of the microscopic pyrite occurs as the small spheres under discussion in the present paper. In a series of beds of uniform grain size and composition, distinct changes of shell shape are related by Eagar, with ‘probable significance’, to the maximum occur- rence of pyrite. Despite the latter, the benthonic population of the area appears to have continued. In fact the change downwards from aerobic to anaerobic conditions can take place at any level in the mud and in this connexion references to studies on the behaviour and effect of bacteria in muds were made in earlier papers (Love 1958, p. 435; L. G. LOVE: MICRO-ORGANISMS AND SYNGENETIC PYRITE 459 Love and Zimmerman 1961, p. 891). Whatever the present organisms may be, the only available records concern bacteria and for these it is clear that at depths of up to fifteen feet into fine subaqueous muds laid down in the absence of current action it is probable that sufficient circulation or migration of iron can occur to allow for much biochemical change and that the chemical system is not a closed one over the distances involved. REFERENCES deans, t. 1948. The Kupferschiefer and the associated Lead-Zinc mineralisation in the Permian of Silesia, Germany, and England. Rep. hit. geo/. Congr., 18th sess., Gt. Britain, Part VII, 340-52. eagar, r. m. c. 1952. Growth and variation in the non-marine lamellibranch fauna above the Sand Rock Mine of the Lancashire Millstone Grit. Quart. J. Geol. Soc. Load. 107, 339-73. 1953. Additions to the non-marine fauna of the Lower Coal Measures of the North-Midlands Coalfields. J. Liv. Manchr. geol. Soc. 1, 328-69. eisenack, a. 1958. Tasmanites Newton 1875 und Leiosphaeridia n.g. als Gattungen der Hystricho- sphaeridea. Palaeontographica, 110, 1-19. hallimond, a. f. et a/. 1950. The constitution and origin of sedimentary iron ores. Proc. Yorks. Geol. Soc. 28, 61-101. Hemingway, J. e. 1934. The Lias of the Yorkshire coast. Proc. Geol. Assoc. 45, 250-60. howarth, m. k. 1955. Domerian of the Yorkshire coast. Proc. Yorks. Geol. Soc. 30, 147-75. kidston, r. and lang, w. h. 1921. On Old Red Sandstone Plants showing structure, from the Rhynie Chert Bed, Aberdeenshire. Part V. The Thallophyta occurring in the Peat-Bed; the succession of plants throughout a vertical section of the bed, and the conditions of accumulation and preservation of the deposit. Trans, roy. Soc. Edinb. 52, 855-902. love, L. g. 1958. Micro-organisms and the presence of syngenetic pyrite. Quart. J. Geol. Soc. Loud. 113 (for 1957), 429-40. 1962. Biogenic primary sulfide of the Kupferschiefer and Marl Slate. Econ. Geol. 56, 350-66. — ■ — • and Murray, J. w. 1963. Biogenic pyrite in recent sediments of Christchurch Harbour, England. Amer. J. Sci. In the press. — — - and zimmerman, d. o. 1961. Bedded pyrite and micro-organisms from Mount Isa Shale. Econ. Geol. 56, 873-96. neeb, i. g. a. 1943. The composition and distribution of the samples. The Snellius Expedition, 5, Pt. 3, Sect. II. Leiden. neuhaus, a. 1940. Uber die Erzfiihrung des Kupfermergels der Hasseler und Groditzer Mulde in Schlesien. Z. angew. Miner. 2, 304-43. neves, r. 1948. Upper Carboniferous plant spore assemblages from the Gastrioceras subcrenatum horizon, North Staffordshire. Geol. Mag. 95, 1-18. Raymond, L. r. 1955. The Rhaetic beds and Tea Green Marl of North Yorkshire. Proc. Yorks. Geol. Soc. 30, 5-23. reid, d. m. 1929. On some factors inhibiting the habitat of Arenicola marina. J. Mar. biol. Ass. U.K. 16, 109-16. Richardson, l. 1905. The Rhaetic and contiguous deposits of Glamorganshire. Quart. J. Geol. Soc. Lond. 61, 385-424. taylor, J. h. 1949. Petrology of the Northampton Sand and Ironstone Formation. Mem. geol. Surv. U.K. van andel, t. and postma, h. 1954. Recent sediments of the Gulf of Paria. Verh. Konink. Ned. Akad. van Wet. afd. Natuurkunde, 20, (5). LEONARD G. LOVE Department of Geology, University of Sheffield, St. George’s Square, Sheffield 1 Manuscript received 25 August 1961 THE SILURIAN TRILOBITE ENCRINURUS PUNCTATUS (WAHLENBERG) AND ALLIED SPECIES by r. p. tripp Abstract. The lectotype pygidium of Encrinurus punctatus (Wahlenberg), the type species, is from the Wenlock Series of the Island of Gotland, in which two allied species of Encrinurus are present ; pygidia are not diagnostic but the size of the lectotype indicates that it should be attributed to the species with larger-sized individuals. An E. punctatus species-group is defined; conformity with the basic arrangement of tubercles on cranidium and pygidium is a necessary, but not sufficient, criterion of inclusion. The group includes also the following species: E. macrourus Schmidt, the smaller species from Gotland; E. tuberculatus (Buckland), a name revived for the British Wenlock form commonly referred to E. punctatus ; E. stubblefieldi sp. nov. from the Ludlow Series of Shropshire; E. onniensis Whittard from the Upper Llandovery of Shropshire, and E. deomenos sp. nov. from the Jupiter Formation of Anticosti Island. The terminology used is unaltered from that of my earlier paper (1957, p. 60) except that the term fossula is used for the anterior pit in the longitudinal furrow. Hamada (1959, p. 83) considers the area between the preglabellar furrow and the facial sutures to be a true preglabellar field, but as Temple (1956, p. 424) points out ‘a true preglabellar field does not bear the axial part of the facial suture and is not typically separated by furrows from the cheeks’. I agree with Temple in considering this area homologous with part of the anterior border of the cranidium in other members of the Cheiruracea. Previous research. Entomostracites punctatus Wahlenberg 1821 has been established as the type species of the genus Encrinurus Emmrich (1844, p. 16), and the pygidium from the Island of Gotland which Wahlenberg figured has been selected as lectotype (Opinion 537 of the International Commission on Zoological Nomenclature). Rosenstein (1941) has published an excellent account of the Estonian form of the species, but un- fortunately her paper is not widely available; she recognized the regularity of arrange- ment of certain cranidial tubercles, and demonstrated that there is a correlation between the positions of the axial and pleural tubercles on the pygidium. Definition of the E. punctatus species-group. Glabella widening markedly forward. Basal lateral lobes almost obsolete, middle and anterior lateral lobes represented by nodular tubercles; similar lateral tubercles on frontal lobe and false preglabellar field. Pairs of large tubercles placed opposite middle and anterior lateral lobes; two or three main rows on frontal lobe. False preglabellar field ill defined, bearing a single row of large tubercles. Fixigenal spines well developed. A column of median, or occasionally submedian, tubercles on axis of pygidium ; typically eight pairs of pleurae each with a tubercle. The following species are here referred to the group: E. macrourus Schmidt, E. tuberculatus (Buckland), E. stubblefieldi sp. nov., E. onniensis Whittard, E. deomenos sp. nov. None of the specimens from Scotland attributed to E. punctatus fall within the group. No specimens from the mainland of North America have been studied. [Palaeontology, Vol. 5, Part 3, 1962, pp. 460-77, pis. 65-68.] R. P. TRIPP: ENCRINURUS PUNCTATUS (WAHLENBERG) 461 System of notation applied to glabellar tubercles. In the present work the system of nota- tion applied to glabellar tubercles by the author in 1957 is adoped (text-fig. 1). The transverse rows of tubercles are numbered I to VI starting from the back; tubercles which occur between the transverse rows are symbolized by the small roman numeral of the row in front; pairs of tubercles are numbered in arabic numerals distally from the centre line. One refinement is necessary: many Silurian species have two tubercles placed one behind the other, between the proximal and lateral tubercles in row III; these tubercles, which may occur singly, are distinguished as II 1-2* and ni-2*. Similarly, the two median tubercles sometimes present between rows III and IV are indicated as iv-0*. The four tubercles in row II are the most consistent in occurrence, but even these are not invariably present (PI. 66, fig. 8), and adventitious tubercles sometimes occur between them (PI. 65, fig. 7). Tubercles which occur on over 90 per cent, of the specimens are regarded as regular, while those on 10 per cent. -90 per cent, are recorded in parentheses in the tubercle formula. The regularity of arrangement of the tubercles on the frontal lobe becomes obscured in heavily tuberculated specimens. The presence or absence of tubercles is not dependent on size of individual ( text-fig. 2); for example, tubercles iii-0 and III-2 are present on even the smallest British specimens but lacking on some of the larger specimens. Acknowledgements. This study has been based entirely on museum specimens, and I am greatly in- debted to the following institutions and individuals who have taken great trouble in supplying me with material. Mr. A. G. Brighton, Sedgwick Museum, Cambridge; Dr. W. T. Dean, British Museum (Nat- ural History), London (BM); Dr. G. Y. Craig, Edinburgh University (EU); Dr. M. L. K. Curtis, City Museum, Bristol; Professor Carl O. Dunbar, Yale University, New Haven, Connecticut (YU); Mr. J. M. Edmonds, University Museum, Oxford (OUM); Professor T. N. George and Dr. E. D. Currie, Hunterian Museum, Glasgow (HM); Dr. J. Ernhold Hede, Paleontologiska Institutionen, Universitet, Lund; Dr. G. Henningsmoen, Paleontological Museum, Oslo (PIO); Dr. V. Jaanusson, Palaeontolo- gical Institute, Uppsala University (PIU); Dr. H. Mutvei, Palaeozoological Dept., Swedish Museum of Natural History, Stockholm (RS); Professor K. Orviku and Dr. R. Mannil, Geological Institute, Tallinn, Estonia (PIT); Professor C. Poulsen, Mineralogical & Geological Museum, Copenhagen, Denmark; Mr. J. D. D. Smith, Geological Survey and Museum, London (GSM); Dr. Isles Strachan, Birmingham University (BU); Dr. C. D. Waterston, Royal Scottish Museum, Edinburgh; Dr. J. Ernhold Hede and Dr. V. Jaanusson have kindly read the manuscript and have most willingly provided much useful information and advice. My special thanks are due to Dr. John Temple, who has assisted at every stage in the work. SYSTEMATIC DESCRIPTIONS Encrinurus pane tat us (Wahlenberg) Plate 65, figs. 9-11, 13-14; Plate 66, figs. 2-3; Plate 67, figs. 5-8; Plate 68, figs. 7, 8, 10 Entomostracites punctatus Wahlenberg 1821, p. 32, pi. 2, fig. 1* (non fig. 1). Encrinurus punctatus Emmrich 1844, p. 16. Encrinurus punctatus Nieszkowski 1857, p. 604, pi. 3, figs. 6, 7. Encrinurus punctatus Schmidt 1881, p. 225, pi. 14, figs. 1 1-13, pi. 15, fig. 18. Encrinurus punctatus Lindstrom 1901, p. 56, pi. 4, figs. 4-9, 12, 13. Encrinurus punctatus Opik 1937, p. 118, pi. 25, fig. 5. Encrinurus punctatus Rosenstein 1941, p. 49, pi. 1, figs. 1-11; pi. 2, figs. 1-3, 5, non 4-4 b\ pi. 3, figs. 1-10. Diagnosis. Glabella strongly convex, standing well above cheeks; cheeks narrow. 462 PALAEONTOLOGY, VOLUME 5 text-fig. 1. Arrangement of glabellar tubercles in cer ain species of the E. punctatus group. A, E. onniensis Whittard, Shropshire, after the syntypeOUM Cl (PI. 65, fig. 16). B, E. tuberculatus (YSucYXmd), Worcestershire, after BM In. 48007 (PI. 65, fig. 7). C, E. punctatus (Wahlenberg), Gotland, after RS Ar. 20320 (PI. 65, fig. 9). D, E. punctatus (Wahlenberg), Estonia, after PIT Tr 1921 (PI. 65, fig. 14). E, E. macrounis Schmidt, Gotland, after RS Ar. 30445 (PI. 65, fig. 4). F, E. stubblefieldi s nov. , Shropshire, after GSM 36846 (PI. 65, fig. 12). Tubercles regarded as adventitious are shaded. R. P. TRIPP: ENCRINURUS PUNCTATUS (WAHLENBERG) 463 Axial furrows deep and narrow. False preglabellar field rarely with a median tubercle. Central body of hypostome strongly convex anteriorly, with median lobe not pro- jecting beyond anterior border. Lectotype. PIU 1200 (pygidium figured Wahlenberg 1821, pi. 2, fig. 1*). Selected and figured by Tripp and Whittard 1956, p. 259, pi. 3, figs. 1, 2. Gotland. Dimensions: Length of pygidium (excluding articulating half-ring) 13-6 mm. Width of pygidium 14-5 mm. Width of axis at front 4-5 mm. Occurrence. Tn Gotland as follows: Upper Visby Marl (Upper Llandovery), Visby. Hogklint Group (Wenlockian), Visby; Lansa, Faro. Slite Group (Wenlockian), Barabacke; Biskops; Eskelhem; Fardume; Follingbo; Klintsvarn; Lergravsviken; Medebys; Myrsjo; Omkr; Slite; Stave; Stormyr; Tjelders; Tofta; Underifran; Utbunge; Vasterhejde; Vastergarn; Wallstena. In Estonia as follows: Jaani Marl (JO, Island of Saaremaa. In Norway as follows: Stage 8d (Monograptus riccartonensis Zone), Malmoya. Description. Cephalon elliptical in outline, strongly convex. Glabella strongly rounded in outline anteriorly, narrowing steadily and strongly backwards to about two-thirds its anterior width; moderately convex longitudinally, strongly convex transversely. Glabella rises well above cheeks at back. Basal glabellar lobe consists of low lateral ridges and an occasional small median tubercle. Middle and anterior lateral lobes represented by nodular tubercles; similar lateral tubercles occur on frontal lobe and on false preglabellar field. These four pairs of tubercles overhang axial furrows. Middle and anterior furrows mere depressions between tubercles. Frontal lobe long. False preglabellar field continuous with glabella in convexity; preglabellar furrow broad and shallow laterally, dying out mesially. Occipital ring moderately arched transversely, considerably broader than posterior part of glabella, somewhat flattened longitudinally; occipital furrow shallow, bowed gently forwards mesially. Axial furrows deep and narrow, deepening abruptly opposite preglabellar furrow and continuing at full depth on to free cheeks; small fossulae at about own diameter behind facial sutures. Apodemes near extremities of lateral glabellar and occipital furrows, immediately inside junctions with axial furrows; occipital pair transversely elongate, basal pair a short distance in front; middle and anterior pairs smaller. A pair of small pits in corresponding positions in preglabellar furrow. Tubercles are usually hemispherical, and sometimes granular; tubercles usually perforate; a single perforation at summit of glabellar tubercles, several perforations may be present on other tubercles. Glabellar tubercle formula: (1-0); II I, 2; (iii-0) ; III-l, (2*), 3; iv-(0*), 1; IV-1, 2, 3; v-(0); V-l, 2, (3); VI-1, (2, 3). Tubercle 1-0 is small, placed close behind row IF Eight, nine (never with one central), or ten tubercles on false preglabellar field; small additional tubercles occasionally present. Fixed cheeks strongly convex, sloping steeply outwards. Palpebral lobes lingulate, almost vertical, rising higher than glabella, situated close to glabella, mid-length opposite middle lateral furrows; palpebral furrows broad and shallow. Posterior borders short (sag.) and transverse proximally, expanding steadily beyond mid-width and curving backwards; a small articulating ledge at back. Posterior border furrows broadest near 3 0 5 0 7-0 9-0 H O 13 0 150 M.M. 3*0 5 0 7-0 0-0 11-0 13 0 I50M M. ZO 15 - lO - 5 - O E. MACROURUS ZO 30 5 0 7-0 90 IIO 13 0 150 M.M. 30 5-0 70 90 II O 13 0 150 M.M. E.PUNCTATUS (GOTLAND) 3-0 5-0 70 3-0 IIO 130 15 O M M. 3-0 50 7-0 30 IIO 13-0 150 M.M. E. TUBERCULATUS text-fig . 2. Histograms illustrating occurrence of certain tubercles in E. tuberculatus, E. punctatus, and E. macrourus. Ordinate — number of specimens. A, shaded — with tubercle iii-0 ; A, unshaded — without tubercle iii-O. B, shaded — with any of the four III-2J tubercles ; B, unshaded — without any of the four III-2* tubercles. Abscissa — length of cranidium in mm. R. P. TRIPP: ENCRINURUS PUNCTATUS (WAHLENBERG) 465 mid-width of cheeks. Lateral borders moderately wide, uniting with posterior borders to form slender fixigenal spines, which are directed backwards and slightly outwards and extend to the fifth thoracic segment. Doublure narrow, widening at genal angles. Anterior branches of facial sutures curve forwards and inwards, crossing axial furrows and separating false preglabellar field from pseudoglabellar areas of free cheeks; posterior branches curve outwards and backwards, crossing lateral borders opposite occipital furrow. Fixed cheeks tuberculate and shallowly pitted (particularly laterally); a column of four large tubercles overhanging axial furrow. Base of palpebral lobe faintly tuberculate. Posterior borders usually smooth, occasionally with a row of low tubercles; a few tubercles near bases of fixigenal spines. Eyes pedunculate, large, visual surface occupies upper half of lobe. Free cheeks large, sloping almost vertically downwards. Pseudoglabellar areas moderately long (exs.) and gently convex. Axial furrows deep, continuous with border furrows. Borders widen gradually forward to axial furrows, and narrow out rapidly in front of pseudo- glabellar areas. Lateral border furrows broad and shallow. Broad depressions run inwards and forwards from axial furrows, separating pseudoglabellar areas from borders. Doublure convex, narrowing forwards and backwards from axial furrows, equal to border in width and sharply upturned proximally. Shallow lateral vincular grooves for accommodation of extremities of posterior thoracic segments when enrolled extend back from mid-length of cheeks. Inner areas of cheeks shallowly pitted, with an irregular arc of four or five tubercles near eyes and one or more tubercles laterally. Tubercles scattered two-deep on pseudoglabellar areas. Lateral borders with a main row of seven tubercles increasing in size forwards, and a smaller, less regular, outer row. Borders and border tubercles more coarsely granular than rest of cephalon. Rostral plate cuneiform, but very variable in shape, narrow, held in an almost vertical position between free cheeks, projecting downwards together with adjacent parts of free cheeks; truncated by rostral suture, occasionally bearing small tubercle; swollen and granular forwards, inturned and narrowing out between doublures of free cheeks at forefront. Hypostome diamond-shaped, four-fifths as wide as long, broadly rounded anteriorly. Central body oval, three-quarters length of hypostome, moderately convex in both directions; longitudinal median lobe projecting and reaching to anterior border, widen- ing slightly and fading out towards back. Maculae strongly swollen, smooth. Anterior border short (exs.), thickened and flexed ventrally downwards at median lobe; border furrow broad laterally, narrowing mesially. Anterior wings large, sloping obliquely upwards, backwards, and outwards, truncate laterally; a rounded wing process near margin. Postero-lateral extensions of wings strongly upturned. Lateral borders narrow, subparallel for a short distance, converging and increasing steadily in width posteriorly, produced into an ogive-shaped tongue. Lateral doublure widens anteriorly to form posterior wings, and posteriorly beneath tongue. Surface of central body and tongue finely granular. Thorax about one and a third times length of cephalon, composed of eleven segments. Axis one-third anterior width of thorax, gently arched transversely, narrowing com- paratively little towards back. Axial rings weakly convex from front to back, bowed forwards mesially, with faint lateral nodes. Articulating half-rings and furrows strongly developed; stout apodemes near extremities of articulating furrows. Indications of a 466 PALAEONTOLOGY, VOLUME 5 broken spine, or a tubercle, on tenth ring. Axial furrows shallow and narrow. Pleurae straight and horizontal to mid-width, directed more or less strongly backwards and downwards laterally. Posterior pleurae bent more strongly downwards and less strongly backwards at fulcrum, which is placed nearer axis. Inner parts of pleurae composed of a broad, gently convex, posterior band, separated by a sharp furrow from a narrow (exs.), depressed anterior band; a ledge at back of posterior band narrows out before fulcrum, and serves to articulate with anterior band of adjacent segment along a slightly sinuous suture line. Laterally, posterior band broadens, pleural furrow narrows, and bevelled articulating facets develop between band and furrow, anterior band forming a narrow border. Lateral margins of posterior bands rounded, lateral margins of articulat- ing facets oblique. (Appearance of internal moulds differs considerably from that of testate specimens in that pleural furrows and ledges are broader, due to differential thickness of shell.) A low tubercle usually placed near fulcrum, successive pleurae sometimes with tubercles placed alternately nearer and farther from axis; additional tubercles sometimes occur. Pygidium excluding mucro longer than cephalon, triangular, approximately as long as wide. Axis weakly arched transversely, narrowing steadily backwards, ill defined posteriorly. First ring the most strongly developed, confluent with first pair of pleurae on external, but not on internal, surface; first ring furrow continuous, but shallower mesially than laterally. Subsequent ring furrows more or less discontinuous mesially, becoming successively shorter and fainter towards back, hindmost obscure; between twenty and thirty rings can usually be counted. Articulating half-ring and furrow al- most as long as first ring. Axial furrows moderately deep posterior to first pleurae, dying out posteriorly. Pleural lobes comparatively wide and moderately convex, sloping downwards with variable steepness, which increases towards back. Eight pairs of raised ribs which widen slightly laterally; ribs broad and flattened on external surface, narrow on internal moulds. First seven pairs of ribs terminate bluntly on lateral margins, eighth die out just beyond apex of axis. Interpleural furrows deep and moderately broad proximally, becoming shallower and narrower laterally; seventh pair do not reach lateral margins. Comparative width of ribs and furrows not consistent between specimens. Mucro of moderate length sometimes developed. Anterior half-pleurae short (exs.), marked off by sharp furrows. Bevelled articulating facets develop laterally between half-pleurae and first ribs, as on thoracic segments. Doublure widens to- wards back; inner margins converge less strongly in posterior one-fourth of their length and meet at an acute angle opposite apex of axis. Doublure granular; a row of five or more perforations pierce test horizontally at extremities of pleurae and along mucro (Rosenstein 1941, pi. 2, fig. 5). Axis of pygidium bears a row of six or seven median tubercles, spaced out at backwardly decreasing intervals. Pleurae bear a tubercle either close to axial furrow, or placed laterally, occasionally in both or intermediate positions. Size of pleural tubercles varies greatly between specimens. Smallest pygidium (2-3 mm. in length) has a short slender mucro; only seven pairs of pleurae present. Remarks. Dr. J. Ernhold Hede has kindly studied the lectotype pygidium. He states that it is from beds which are certainly younger than the Upper Visby Marl and older than the Klinteberg Group; that its age is without doubt Wenlockian, and that it is most probably from the Hogklint Group (for stratigraphical table see Hede 1960, pp. 47-52). R. P. TRIPP: ENCRINURUS PUNCTATUS (WAHLENBERG) 467 Two species of Encrinurus of the punctatus type occur in the Wenlock Series of Got- land, and unfortunately the pygidia cannot be distinguished morphologically. The most common is a comparatively large form, with 2n limits for length of cranidium of 4-8-12-5 mm., compared with 4-0-8-4 mm. for the smaller species. The lectotype is a large non- mucronate pygidium measuring 13-6 mm. in length; comparison with entire specimens shows that the length of the cranidium is 15-20 per cent, less than that of the pygidium, indicating a cranidial length of 10-8-11-6 mm. for the type. It is reasonably certain, therefore, that the type pygidium is conspecific with the larger cranidia. Such morphological evidence as is available — the greater convexity for in- stance— supports this view. The smaller form is referred to E. macrourus (see below), a species which becomes common in the Ludlow series. Specimens of E. punctatus from the Hogklint Group, the Slite Group and Estonia differ in size and there are considerable variations in the arrangement of glabellar and preglabellar tubercles (see Table 1). The posterior tongue of the hypostome from Estonia, figured PI. 67, fig. 5, is short, though slightly abraded. Encrinurus tuberculatus (Buckland) Plate 65, figs. 5-8; Plate 66, figs. 4-11; Plate 67, figs. 9-10; Plate 68, figs. 4-6 Calymene variolaire Brongniart 1822, pi. 1, fig. 3 a (non fig. 3b). Asaphus tuberculatus Buckland 1836, vol. 2, p. 74, pi. 46, fig. 6. (=pl. 1 fig. 3 a in Brongniart 1822). Cvbele punctata Fletcher 1850, p. 158, pi. 32, figs. 1-5. Encrinurus punctatus Salter 1853, p. 6, pi. 4, figs. 15, 16 ( non fig. 14). Diagnosis. Glabella strongly convex, standing well above cheeks. Axial furrows deep and narrow. Glabella strongly tuberculate. Rostral plate protuberant. Central body of hypostome weakly convex anteriorly with median lobe ‘waisted’, not projecting beyond anterior border. Holotype. Specimen figured by Buckland 1836, pi. 46, fig. 6 (dorsal shield). Present whereabouts unknown. Wenlock Limestone, Dudley, Worcestershire. Occurrence. In Britain as follows: Woolhope Limestone, Malvern Tunnel, Worcestershire. Wenlock Limestone and Shale, Dudley, Worcestershire; Much Wenlock, Shropshire; Colwall and Malvern, Herefordshire; Walsall, Staffordshire; Pen-y-lan, near Cardiff, Glamorgan. Description. Cheeks broader compared with glabella than in type form. Glabellar tubercle formula (1-0); II- 1, 2; iii-0; III-l, 2*,3;iv-0J, 1 ;IV-1,2,3; v-0; V-VI-1,2,3. Adventitious tubercles commonly occur particularly on the frontal lobe. Typically with eight tubercles on false preglabellar field. Eye lobes more slender and higher, and situated further forward — opposite anterior lateral glabellar lobes — and farther from glabella. A con- spicuous row of tubercles at base of palpebral lobe. Pseudoglabellar areas of free cheeks longer (exs.), tubercles sometimes three-deep. Front part of the appropriately named rostral plate, together with adjacent parts of cheeks, projects forwards and downwards like a beak. Hypostome more strongly rounded in anterior outline; longitudinal con- vexity weak anteriorly. Median lobe not projecting beyond anterior border, more strongly arched transversely, longer and distinctly ‘waisted’ near mid-length. Anterior border of hypostome flexed more strongly mesially. Posterior tongue longer. Central Hh C 674 468 PALAEONTOLOGY, VOLUME 5 body and tongue more coarsely granular; numerous smooth, transverse depressions on central body may be areas of muscle attachment. Axis of thorax less than one-third width of thorax anteriorly. Indications of a median broad-based axial spine almost always present on tenth thoracic ring, sometimes also on seventh, ninth, or eleventh rings. When preserved spine curves backwards and extends for about one and a half times width of ring. Mucro of pygidium usually of moderate length, sometimes upcurved, never absent. Remarks. Buckland’s explanation of his pi. 46, fig. 6 is as follows: ‘Asaphus tubercula- tus; a highly ornamented species from the Transition lime-stone of Dudley; in the col- lection of Mr. Johnson, of Bristol. The back alone is composed of flexible plates.’ (Curtis.) Parts of Mr. Jas. R. Johnson’s Collection are in the City Museum, Bristol, and in the British Museum (Natural History), but there is no trace of this specimen. Many specimens of E. tuberculatus and E. macrourus are preserved with the hypostome in position. The hypostome fits exactly against the doublure of the cephalon along the sinuous hypostomal suture, the rostral plate and adjacent parts of the free cheeks EXPLANATION OF PLATE 65 All photographs are of testate specimens unless otherwise stated. The specimens were coated with ammonium chloride before being photographed. Figs. 1-4. Encrinurus macrourus Schmidt. 1, Klinteberg Group (Lower Ludlovian), Eksta, Gotland. RS Ar. 30206, X 4. The median preglabellar tubercle off-centre. 2, Hogklint Group (Wenlockian), Kappelshamn, Gotland. PIU, X 5. The median preglabellar tubercle off-centre. 3, Klinteberg Group (Lower Ludlovian), Eksta, Gotland. RS Ar. 30673, X 6. 4, Hemse Group (Lower Ludlovian), Petesviken, parish of Hablingbo, Gotland. RS Ar. 30445, x6. No inter-row tubercles present; eight preglabellar tubercles. Figs. 5-8. Encrinurus tuberculatus (Buckland). 5, Wenlock Limestone, Dudley, Worcestershire. OUM C368, x4. Sparsely tuberculated specimen. 6, Wenlock Shale, Malvern, Herefordshire. GSM Z.4103, X 3. A typical specimen; inter-row tubercles iv-0*, 1 present. 7, Wenlock Shale, Malvern, Herefordshire. BM In. 48007, x4. Heavily tuberculated specimen, with adventitious tubercles in row II. 8, Wenlock Limestone, Dudley, Worcestershire. GSM 36304, X 3£. Five preglabellar tubercles on the right side. Figs. 9-11. Encrinurus punctatus (Wahlenberg). 9, Slite Group (Wenlockian), Eskelhem, Gotland. RS Ar. 20320, x3. Five preglabellar tubercles on the left side. 10, Slite Group (Wenlockian), Follingbo, Gotland. RS Ar. 47293, x4. Heavily tuberculated specimen; probably ten preglabellar tubercles. 11, Hogklint Group (Wenlockian), ‘Vattenfallet’ (the ‘Waterfall’), Visby, Gotland. RS Ar. 30479, x3. Fig. 12. Encrinurus stubblefieldi sp. nov., ‘Upper Ludlow Shales,’ Whitcliff, Shropshire, GSM 36846 (the holotype), X 6. Internal mould. Figs. 13-14. Encrinurus punctatus ( Wahlenberg). Jaani Marl, Jaani, Saaremaa, Estonia. 13, PIT Nr 1920, tubercle iii-0 lacking. 14, PIT Tr 1882 (Bolau Collection), X 3. Exceptionally large specimen; figured by Rosenstein 1941, pi. 1, figs. 1-4. Fig. 15. Encrinurus sp. Damery Beds, Woodford, near Tortworth, Gloucestershire. BM In. 54000, X 4. Internal mould. Fig. 16. Encrinurus onniensis Whittard. Purple Shales (Upper Valentian), Onny River Section, near Cheney Longville, Shropshire. OUM Cl, x4. Internal mould. gs. 17-20. Encrinurus variolaris (Brongniart). 17, Wenlock Limestone, Dudley, Worcestershire. BU H723 (Holcroft Collection), x4. Note coalescence of a pair of tubercles in row I. 18, Wenlock Shale, Malvern, Herefordshire. OUM C372, X 5. 19, Wenlock Limestone, Dudley, Worcestershire. BU 724 (Holcroft Collection), X 8. 20, Wenlock Limestone, Dudley, Worcestershire. BU 725 (Holcroft Collection), x 4. A median tubercle in row I. Palaeontology , Vol. 5 PLATE 65 9 10 II 12 13 14 15 16 TRIPP, Encrinurus R. P. TRIPP: ENCRINURUS PUNCTATUS (WAHLENBERG) 469 projecting downwards in conformity with the median flexure of the anterior border of the hypostome. When held in this position the wing processes appear to be in contact with the fossulae (PL 67, fig. 2) and the tip of the tongue lies opposite the posterior margin of the occipital ring and comparatively close to it (PI. 66, fig. 4b). The proximity of the projecting rostral plate to the median lobe of the hypostome would prevent any appreci- able rocking action, so practically no movement can have been possible. The same condition applies in the case of E. variolaris (Brongniart); Temple (1954, p. 317) writes: ‘The cephalon and hypostome of E. variolaris seem to have formed together a rigid whole, for it is unlikely that any movement could have taken place during life along the curved hypostomal suture or the facial sutures, although there may have been sulficient elasticity in the integument to allow a very small amount of bending to occur.’ Rosenstein (1941, p. 60) demonstrated that in Estonian Encrinurus pygidia there is a correlation between the positions of the axial and pleural tubercles; 94 per cent, of specimens with the first tubercle on the first ring have the tubercle on the second pleurae farther from axis than the others; 75 per cent, of specimens with the first tubercle on the second ring have the tubercle on the third pleurae the farthest from the axis. The percentage of specimens which demonstrate this correlation is much larger in E. punctatus than in E. tuberculatus, even when specimens which show a slight displace- ment, or a displacement on one side only, are included (see Table 1). The synonymy of E. punctatus calcar eus Salter (1853, p. 6) cannot be established at present. Woolhope is the principal, if not the only, locality mentioned by Salter, but there are no specimens from the Woolhope Inlier in the collections studied. Plate 65, figs. 1-4; Plate 66, figs. 1 a-c; Plate 67, figs. 1-4; Plate 68, figs. 1-3, 9 Encrinurus punctatus var. macrourus Schmidt 1 859, p. 438. Encrinurus punctatus Rosenstein 1941, pi. 2, figs. 4-4 b. Diagnosis. Glabella widening strongly towards front, weakly convex, rarely rising above cheeks at back. Axial furrows broad. Usually nine tubercles on false preglabellar field, one medial. Central body of hypostome weakly convex anteriorly, with median lobe projecting beyond anterior border. Lectotype. PIT Tr 1905 (thorax and pygidium). PI. Ill, figs. 4a , b. Hemse Group (Lower Ludlovian), Petesviken, parish of Hablingbo, Gotland. Selected hereby. Dimensions: Occurrence. In Gotland as follows: Lower Yisby Marl (Upper Llandovery)?; Norderstrand. Upper Visby Marl (Upper Llandovery), Lummelunda; Visby. Hogklint Group (Wenlockian), Kapelshamn; Visby. Slite Group (Wenlockian), Klintsgvarn; Slite. Mulde Marie (Wenlockian), Frojel. Klinteberg Group (Lower Ludlovian), Eksta. Hemse Group (Lower Ludlovian), Garsby; Kvinngarde; Linde; Petesviken; Sandarve; Visne Myr. Description. Differs from E. punctatus in the following features. Dorsal shield less vaulted. Glabella widens more strongly anteriorly and is less convex rarely rising above Encrinurus macrourus Schmidt Length of pygidium (extremity broken) 9-0 mm. Width of pygidium Anterior width of axis 7-8 mm. 2-9 mm. 470 PALAEONTOLOGY, VOLUME 5 height of cheeks at back. The four pairs of lateral tubercles tend to be smaller. Fewer tubercles on glabella; tubercles conical or hemispherical. Glabellar tubercle formula: (1-0); II-l, 2; III-l, (2*), 3; iv-(0*, 1); IV-1, 2, 3; (v-0); V-l, 2, (3); VI-1, (2, 3). Basal lateral ridges more distinct. Typically with nine tubercles on false preglabellar field, one medial. Axial furrows broader, curving more strongly inwards. Fixed cheeks less convex sloping gently inwards to axial furrows; proximal tubercles smaller than others, not overhanging axial furrows. Eye lobes more slender placed farther apart. Pseudo- glabellar areas of free cheeks shorter, bearing fewer tubercles, marked off from borders by fainter depressions. Rostral plate broader and shorter, subpentagonal, usually with a tubercle proximally; swollen forwardly. Central body of hypostome less convex an- teriorly; median lobe broader, with less independent convexity and projecting for- wards beyond anterior border; maculae less inflated. Median part of anterior border of hypostome less thickened and less flexed; anterior border furrow narrow, faint medially. Central body and tongue more coarsely granular. Usually with a tubercle, rarely a spine, on tenth thoracic ring, sometimes on seventh or on both. Spaces between pleural ribs of pygidium sometimes exceptionally broad with low, faintly granular ridges running parallel to the ribs. Exoskeleton tends to be preserved enrolled, with hypostome in place. In this position the pygidium lies neatly against the doublures of the free cheeks, the projecting rostral plate fitting into the narrow V formed by the inner margins of the pygidial doublure (PI. 66, fig. 1). Remarks. Pygidia of E. punctatus amd E. macrounis show so great a range of variation in convexity, length of mucro, strength of axial and interpleural furrows, size, number, and position of tubercles that specific differentiation is impossible. Whittard (1938, p. 119) has already drawn attention to the value of the hypostome and rostral plate in distinguishing species of Encrinurus. The low ridges described above as running parallel to the ribs in the pygidia (PI. 67, EXPLANATION OF PLATE 66 Figs. 1 a-c. Encrinurus macrourus Schmidt. Klinteberg Group (Lower Ludlovian), Eksta, Gotland. RS Ar. 30206, x3. Enrolled dorsal shield. Dorsal, lateral, and frontal views; see PI. 65, fig. 1. Figs. 2-3. Encrinurus punctatus (Wahlenberg). 2a, b, Slite Group (Wenlockian), Follingbo, Gotland. RS Ar. 30221, X 3. Enrolled dorsal shield. Dorsal and lateral views. Fig. 3. Slite Group (Wenlockian) Eskelhem, Gotland. RS Ar. 20320, X 2\. Dorsal shield. Frontal view: see PI. 65, fig. 9. Figs. 4-1 1. Encrinurus tuberculatus (Buckland). 4a- c, Wenlock Shale, Malvern Tunnel, Herefordshire. OUM C318 (Grindrod Collection), x4. Cephalon. Dorsal, lateral and anterior views. 5, Wenlock Shale, Dudley, Worcestershire. BM I 2160, x2. Cephalon and thoracic segments. 6, Woolhope Shale, Malvern, Herefordshire. BU 727 (Ketley Collection), x3t. Incomplete dorsal shield. Lateral view showing impression of axial spine on tenth thoracic ring and upturned pygidial mucro. 7, Wenlock Limestone, Dudley, Worcestershire. EU A 133, x2. Cranidium with basal lateral ridges well developed; palpebral lobe strongly tuberculate. 8, Wenlock Limestone, Malvern Tunnel, Herefordshire. BM In. 42623, X 3-|. Specimen with three instead of the usual four tubercles in row II of the glabella. 9, Wenlock Limestone, Dudley, Worcestershire. BU 728 (Ketley Collection), X 2. Pygidium. Lateral view, showing articulating facet. 10, Wenlock Shale, Malvern, Herefordshire. OUM C160 (Grindrod Collection), X 2. Elongate dorsal shield. 11, Woolhope Shale, Malvern, Herefordshire. BU 729 (Ketley Collection), X 2. Thorax and pygidium. Axial spine on tenth thoracic ring. Palaeontology , Vol. 5 PLATE 66 TRIPP, Encrinurus 471 R. P. TRIPP: ENCRINURUS PUNCTATUS (WAHLENBERG) fig. 3) are considered homologous with the anterior bands of pleurae in cybelid pygidia, indicating that the ribs are equivalent to the posterior bands only, not to the fused posterior band of one pleura and the anterior band of the next, the generally accepted view first promulgated by Barrande (1852, pp. 216-17). Encrinurus stubblefieldi sp. nov. Plate 65, fig. 12; Plate 67, figs. 14-15; Plate 68, fig. 11 Diagnosis. Cranidium broad, weakly convex. Basal lateral ridges of glabella well de- veloped; only two rows of tubercles on frontal lobe. Eight tubercles on false preglabellar field. Seven pairs of pleurae in pygidium. Holotype. GSM 36846 (internal mould of cranidium). PI. 65, fig. 12; PI. 67, fig. 15. "Upper Ludlow Shales’, Whitcliff, Shropshire. Dimensions: Median length of cranidium 5-6 mm. Width of cranidium (est.) 22-5 mm. Width across false preglabellar field 5-2 mm. Width of glabella across basal lobes 3-2 mm. Paratype. GSM 36844 (internal mould of cranidium, thoracic segments, and pygidium). PI. 67, fig. 14. ‘Upper Ludlow Shales’, N. E. Pilliard’s Barn, Shropshire. Occurrence. ‘Lower Ludlow Shales’. Leintwardine, Shropshire. ‘Upper Ludlow Shales’, Whitcliff and N.E. Pilliard’s Barn, Shropshire. Description. Differs from E. punctatus in the following features. Cranidium is broad and only weakly convex. Glabella widens less towards front. Glabellar tubercle formula: 1-1 ; II- 1, 2; (iii-0) ; HI-1, 2 (*), 3; iv-(0*, 1); IV-1, 2, 3; (v-0); V-l, 2, (3). Basal lateral ridges extend to a median pair of tubercles or a single tubercle. Axial furrows broader and shallower. Cheeks broader compared with glabella. Palpebral lobes placed farther from glabella; palpebral furrows deeper and broader. Tubercles on cheeks smaller and more numerous. Lixigenal spines and adjacent borders much broader. Posterior borders finely tuberculate. Thorax narrower than cranidium and narrowing more strongly towards back. Axis less than one-third anterior width of thorax. No indication of presence of axial spines. Pleural tubercles larger, situated at varying distances from axis. Pygidium shorter, composed of about eighteen rings and seven pairs of pleurae. Three or four axial tubercles, first on third ring. Pleural tubercles faint, placed fairly close to axis. Mucro slender, about half length of axis. Remarks. No described species appears to be closely related to E. stubblefieldi. Encrinurus onniensis Whittard Plate 65, fig. 16; Plate 67, fig. 16 Encrinurus onniensis Whittard 1938, p. 118, pi. 4, figs. 6-10 ( non fig. 11). 472 PALAEONTOLOGY, VOLUME 5 Diagnosis. Glabella pyriform, narrow, less elevated than cheeks at back. Eight tubercles on false preglabellar field. Eye lobes small. Syntypes. GSM 55488 and 55489 (counterparts of an exoskeleton); OUM Cl (internal mould of a dorsal shield). Occurrence. Purple or Hughley Shales (Upper Llandovery), Onny River Section, near Cheney Long- ville, Shropshire. Remarks. The glabellar tubercle formula of the syntype OUM Cl (PI. 65, fig. 16; PI. 67, fig. 1 6) is as follows ; 1 -0 ; II- 1 , 2 ; iii-0 ; III- 1,2*, 3; iv-1 ; IV-1,2, 3; V-VI- 1 , 2. A cranidium from the arenaceous Purple Shales of the Bog Mine Inlier (BM In. 22533) has thirteen tubercles on the false preglabellar field, and does not belong to the species-group. Pygidia from this locality (Whittard 1938, pi. 4, fig. 11) are more triangular, more strongly vaulted and are non-mucronate. EXPLANATION OF PLATE 67 Figs. 1-4. Encrinurus macrourus Schmidt. 1, Hemse Group (Lower Ludlovian), Visne Myr, parish of Fardhem, Gotland. RS Ar. 30415, X 6. Hypostome. 2, Gotland (exact locality and horizon un- known). RS Ar. 47146, x 8. Left lateral view of inverted cephalon to show articulation of cranidium and hypostome. Left free cheek removed, rostral plate in position; longitudinal median lobe of hypostome projects beyond anterior border. Wing process of hypostome rests against fossula near front of axial furrow; wing extends forwards close to axial furrow well beyond facial suture; posterior part of the wing is upturned, running subparallel to steeply sloping part of the axial furrow. 3, Klinteberg Group (Lower Ludlovian), Eksta, Gotland. RS Ar. 30674, X 6. Pygidium. Oblique view showing ridges between ribs, considered equivalent to anterior bands of cybelids. 4a, b, Hemse Group (Lower Ludlovian), Petesviken, parish of Hablingbo, Gotland. PIT Tr 1905 (lectotype), X 3. Thorax and pygidium; axial tubercles on seventh and tenth thoracic rings. Dorsal and lateral views. Photos kindly supplied by Dr. R. Mannil. Pigs. 5-8. Encrinurus punctatus (Wahlenberg). 5, Jaani Marl, Jaani, Saaremaa, Estonia. PIT Nr. 1922 (Luha Collection), X4. Hypostome. 6, Jaani Marl, Jaani, Saaremaa, Estonia. PIT Tr 1882. (Bolau Collection), x2. Cephalon. Oblique lateral view showing apodemal pits; see PI. 65, fig. 14. 7, Slite Group (Wenlockian), Follingbo, Gotland. RS Ar. 47294, X 4. Doublure of pygidium. 8 a, b, Slite Group ( Wenlockian), Vikers, parish of Boge, Gotland. RS Ar. 30223, x4. Hypostome figured by Lindstrom, 1901, pi. 4, figs. 5, 6, 12, 13. Plan and anterior views. Figs. 9-10. Encrinurus tuberculatus (Buckland). 9a, Wenlock Shale, Malvern, Herefordshire. BM In. 48008, X 3. Hypostome. 9b, the same, X 2. Ventral view of cephalon, showing underside of right axial furrow; arrow points to the facial suture, fossula lies close behind. 10, Wenlock Limestone, Malvern, Herefordshire. BM In. 48015, X 3. Anterior view of inverted cephalon; rostral plate and part of left free cheek removed. Note strong median flexure of anterior border of hypostome. Figs. 1 1-13. Encrinurus deomenos sp. nov. 11, Jupiter Formation, The Jumpers, Anticosti Island. HM A. 884, x3. Cranidium. 12, Zone 4, Jupiter Formation, Sandcliff, Anticosti Island, YU 882 (holo- type), x 8. Anterior view of cephalon, showing free cheeks in contact and absence of rostral plate. 13, Zone 1, Jupiter Formation, East Cliff, west of Jupiter River, Anticosti Island. YU 10402, x3. Hypostome probably belonging to this species; figured by Twenhofel 1928, pi. 59, fig. 7 as E. anticostiensis. Figs. 14-15. Encrinurus stubblefieldi sp. nov. 14, ‘Upper Ludlow Shales’, N. E. Pilliards Barn, Shrop- shire. GSM 36844 (paratype), x3. Cranidium and thorax. Internal mould. 15, ‘Upper Ludlow Shales’, Whitcliff, Shropshire. GSM 36846 (holotype), x 2. Cranidium; see PI. 65, fig. 12. Internal mould. Fig. 16. Encrinurus onniensis Whittard. Purple Shales (Upper Valentian), Onny River Section, near Cheney Longville, Shropshire. OUM Cl, x 2. Dorsal shield; see PI. 65, fig. 16. Internal mould. Palaeontology, Vol. 5 PLATE 67 TRIPP, Encrinurus R. P. TRIPP: ENCRINURUS PUNCTATUS (WAHLENBERG) 473 Encrimtrus sp. Plate 65, fig. 15 Calymene ? punctata Murchison 1839, p. 661, pi. 23, fig. 8a. Encrinurus onniensis Curtis 1958, p. 142, pi. 29, figs. 4-5. Occurrence. Damery Beds and Palaeocyclus Band at base of Tortworth Beds (Upper Llandovery), Tortworth Inlier, Gloucestershire. Remarks. Cranidia from the Damery Beds differ considerably from E. onniensis in that the glabella is broader anteriorly, the glabella stands well above the fixed cheeks at the back, the lateral glabellar tubercles are larger, and there are ten small tubercles on the false preglabellar field. Associated free cheeks are much narrower than in E. onniensis, and pygidia are narrower and more strongly vaulted. Better preserved cranidia are required before the species can be described adequately. Encrinurus deomenos sp. nov. Plate 67, figs. 11-13; Plate 68, fig. 12 Encrinurus anticostiensis Twenhofel 1928, pi. 59, figs. 6-8, 10 (non fig. 9). Diagnosis. Cephalon strongly arched transversely. Glabella short, rounded, inflated, standing much higher than cheeks. Glabella densely tuberculated. Rostral plate lacking. Holotype. YU 882 (enrolled dorsal shield). PI. 67, fig. 12. Twenhofel, 1928, pi. 59, fig. 10. Dimensions; Median length of cranidium 7-2 mm. Width of cranidium 15-0 mm. Width across false preglabellar field 6-3 mm. Width of glabella across basal lobes 3-5 mm. Occurrence. Jupiter Formation, Anticosti Island. Description. Differs from E. punctatus in the following features. Cephalon more strongly arched transversely. Glabella rounded, more inflated, standing high above cheeks at back. The four pairs of nodular lateral lobes considerably larger than other glabellar tubercles. Glabellar tubercle formula: (1-0); II- 1, 2; iii-0; III-l, 2*, 3; iv-1; IV-1, 2, 3; (v-0); V-VI-1, 2, 3. Pseudoglabellar areas of free cheeks comparatively short, but broad, bearing eleven or twelve tubercles arranged in two irregular rows. Rostral plate lacking; a median suture separates free cheeks. Hypostome elongate; median lobe of central body short, widening towards back, not overhanging anterior border; posterior tongue long. Spine-bases occur on seventh and tenth axial rings. Pygidium strongly arched transversely; tubercles faint. Mucro slender, half length of axis. Remarks. The dorsal shield which Twenhofel selected as holotype of E. anticostiensis (1928, pi. 59, fig. 9) is quite different from the other specimens attributed to the species (figs. 6, 8, 10), all of which, including the hypostome (fig. 7), show affinities with the E. punctatus species-group, and are attributed to the one species. The absence of rostral plate is demonstrated both in the holotype of E. deomenos and in a second specimen in the Yale University Collection. 474 PALAEONTOLOGY, VOLUME 5 COMPARISON OF THE E. PUNCTA TUS GROUP WITH OTHER SPECIES The limit which has been set to the E. punctatus group is arbitrary. The most closely related species is one from the Hemse Group of Lau, Gotland; in this, nodular basal lateral lobes are developed, the glabellar tuberculation is more irregular and there is a tubercle in front of the lateral tubercle on the false preglabellar field. A group of species including E. calgach Lamont MS. is excluded because the median pair of tubercles in row II is displaced forwards, and there is a pair of equally large tubercles immediately behind them. Several Silurian species resemble E. punctatus in glabellar tuberculation, although they are unrelated. Plate 65 has been arranged to illustrate similar variations which occur in E. variolaris (Brongniart) and in species of the- E. punctatus group. In the first column of illustrations (figs. 1, 5, 9, 13, 17) the specimens lack tubercle III-2; in the second column this tubercle is forwardly placed (III-2*); in the third column it is paired (III-2*), and in the fourth column (excluding fig. 16) tubercles III-l, 2, 3 are in line. E. moe from the Yormsi Stage (F^) of Estonia has recently been described by Mannil (1958, p. 193, pi. 7, figs. 1-4, pi. 8, fig. 13). This species provides an interesting link be- tween E. punctatus and the E. multisegmentatus (Portlock) groups, despite conspicuous differences from both. Row II consists of two pairs of tubercles, row III of three pairs, the second pair forwardly placed, as in E. punctatus. Nodular lateral tubercles occur. The basal glabellar lobes are strongly developed, and the false preglabellar field is divided by a median depression, as in E. multisegmentatus. Mannil considers that the rostral plate has not been preserved, but in view of the straight connective suture be- tween the free cheeks, it seems more probable that this species, like E. deomenos, lacked the rostral plate. EXPLANATION OF PLATE 68 Figs. 1-3, 9. Encrinurus macrourus Schmidt. 1, Klinteberg Group (Lower Ludlovian), Eksta, Gotland. RS Ar. 30675, x5. Pygidium with short mucro; pleural tubercles faint, all placed close to axis. 2, Hemse Group (Lower Ludlovian), Visne Myr, parish of Fardhem, Gotland. RS Ar. 30215, X 1-75 Pygidium with long mucro. 3, Klinteberg Group (Lower Ludlovian), Eksta, Gotland. RS Ar. 30674, x5. Enrolled dorsal shield showing pygidium with no mucro and ridges between ribs; see PI. 67, fig. 3. 9, Hemse Group (Lower Ludlovian), Kvinngarde, parish of Havdhem, Gotland. RS Ar. 47295, X 5. Pygidium with short mucro, faint pleural tubercles, and narrow interpleural furrows. Figs. 4-6. Encrinurus tuberculatus (Buckland). 4, Wenlock Limestone, Dudley, Worcestershire. BM In. 48020, x3. Pygidium with short mucro; first axial tubercle on third ring, the faint pleural tubercles placed close to axis. 5, Wenlock Limestone, tunnel under Wren’s Nest, Dudley, Worcester- shire. BU 726 (Holcroft Collection), X 3. Pygidium with long mucro. 6, Wenlock Limestone, tunnel under Wren’s Nest, Dudley, Worcestershire. BU 805 (Holcroft Collection), x 5. Pathological pygidium, showing deranged axial rings; large mucro broken off. Figs. 7, 8, 10. Encrinurus punctatus (Wahlenberg). 7, Jaani Marl, Jaani, Saaremaa, Estonia. PIT Nr. 1923, X 5. Pygidium with short mucro. 8, Stage 8d, Malmoya, Norway. P10 44662, X 6. Pygidium with long mucro broken off. 10, Slite Group (Wenlockian), Omkr, parish of Bunge, Gotland. RS Ar. 47296, x4. Pygidium; the fourth axial tubercle paired. Fig. 11. Encrinurus stubblefieldi sp. nov. ‘Upper Ludlow Shales’, Whitcliff, Shropshire. GSM 36847, x3. Pygidium. Internal mould. Fig. 12. Encrinurus deomenos sp. nov. Zone 1, Jupiter Formation, East Cliff, west of Jupiter River, Anticosti Island. YU 10397, x4L Pygidium. Figured Twenhofel 1928, pi. 59, fig. 8, as E. anticos- tiensis. Palaeontology, Vol. 5 PLATE 68 TRIPP, Encrinurus R. P. TRIPP: ENCRINURUS PUNCTATUS (WAHLENBERG) 475 Table 1 Comparison of E. punctatus, E. tuberculatus, and E. macrourus Species punctatus tuber- culatus macrourus Country : GOTLAND ESTONIA BRITAIN GOTLAND Horizon: U. VJSBY MARL HCGKLINT GROUP SL1TE GROUP Total JAANI MARL WENLOCK SERIES U. LLANDOVERY WENLOCK SERIES LUDLOW SERIES Number of cranidia studied: I 8 31 40 8 119 9 8 42 85 Length of cranidium. Mean length (mm.) 100 10-6 81 8-7 61 94 6-9 6-9 6-2 6-2 Length of cranidium 2 a limits (mm.) 7-8 4-7 4-8 1-6 5-6 51 4 1 3-8 40 13-4 11-5 12 5 10 6 13-2 8-6 9-8 8-6 8-4 % of specimens with tubercle iii-0 100 100 81 85 12 93 0 25 2 6 % of specimens with any of the 4 III— 2^ tubercles 100 100 35 50 50 97 45 38 57 46 % of specimens with 8 preglabellar tubercles ? 66 14 23 100 87 29 0 21 18 % of specimens with 9 preglabellar tubercles 0 14 12 0 5 71 80 69 73 % of specimens with 10 or more preglabellar tubercles 34 72 65 0 8 0 20 10 9 Number of pygidia studied: 1 6 7t 16 144 4 1 73 96 % of specimens with first tubercle on first axial ring 17 14 32 10 0 0 5 5 % of specimens with first tubercle on second axial ring 100 83 86 68 80 75 0 67 71 % of specimens with first tubercle on third axial ring 0 0 Of 0 10 25 100 28 24 % of specimens showing correlation of position of axial and pleural tubercles as mentioned on p. 469 . 0 83 72 75 43 * Includes 26 cranidia and 18 pygidia of unknown locality. t Only entire dorsal shields included. Certain isolated pygidia with first tubercle on third axial ring are almost certainly attributable to E. punctatus. ADDENDUM Mr. R. V. Best’s interesting study of Encrinurus ornatus Hall & Whitfield (1961, Journ. Paleontology, 35, 1029-40, pi. 124) was not seen until after this paper had been submitted for publication. From his study of the number of rings between the first and second and second and third axial tubercles of the pygidium, Best was able to demon- strate the random binomial distributions of combinations of three-ring and four-ring spacing of these tubercles, suggesting that his collections came from an interbreeding population. This method of study cannot be applied to the species studied in this paper because the number of rings between the first three tubercles is more variable. The 476 PALAEONTOLOGY, VOLUME 5 following count of adequately preserved specimens is provided for comparison with Best’s Table 1. Species: E. tuberculatus E. macrourus E. spp. Wenlock Series of Gotland First tubercles on ring no: 1 2 3 1 2 3 1 2 3 Number of rings be- tween first and third tubercles Total Total Total 10 - 1 - 1 - - - - - 1 1 9 1 42 6 49 - 10 6 16 - 10 2 12 8 5 39 8 52 1 28 9 38 5 32 10 47 7 6 26 1 33 4 17 5 26 3 23 2 28 6 2 - - 2 - 3 - 3 5 13 1 19 Total number of specimens 14 108 15 137 5 58 20 83 13 78 16 107 REFERENCES barrande, J. 1852. Systeme silurien du centre de la Boheme: lere partie, Crustaces, Trilobites, 1, 1-935, pi. 1-51. brongniart, a. 1822. Histoire naturelle des Crustaces fossiles. . . Les Trilobites. Paris. buckland, w. 1836. Geology and mineralogy considered with reference to natural theology, Bridgewater treatise, 2, 1-128, pi. 1-69. curtis, m. l. k. 1958. The Upper Llandovery Trilobites of the Tortworth Inlier, Gloucestershire. Palaeontology, 1, 139-46, pi. 29. dalman, J. w. 1827. Om Palaeaderna eller de sa kallade Trilobiterna. K. Svenska Vet. Hand!. 1, 226-94, pi. 1-6. emmrich, h. f. 1844. Zur Naturgeschichte der Trilobiten. Meiningen. fletcher, t. w. 1850. Observations on Dudley Trilobites — Part 2. Quart. J. geol. Soc. Lond. 6, 402-5, pi. 32. hamada, t. 1959. Gotlandian Shelly Fauna from Southwest Japan (1). Coroncephalus kobayashii, a new Species from the Kuraoka District, Kyushu. Japanese J. Geol. Geog. 30, 71-88, pi. 6. hede, J. ernhold. 1960. The Silurian of Gotland. Guide to Excursion C 17, International Geological Congress, XXI session. Copenhagen. lindstrom, g. 1901. Researches on the visual organs of the trilobites. Stockh. Vet. Akad. Handl. 34, 1-87, pi. 1-6. mannil, r. 1958. Trilobites of the families Cheiruridae and Encrinuridae from Estonia. (In Russian with Estonian and English summaries.) Eesti NSV Teaaduste Akad., Geol. Inst. Uurimused, 3, 165-212, pi. 1-8. Murchison, r. l. 1839. The Silurian System. London. nieszkowski, J. 1 857. Versuch einer Monographic der in den silurischen Schichten der Ostseeprovinzen vorkommenden Trilobiten. Archiv Naturk. Liv-, Ehst- u. Kurl. 1, 1-157, pi. 1-3. opik, a. a. 1937. Trilobiten aus Estland. Acta Comment. Univ. Tartu. A, 32, 1-163, pi. 1-26. rosenstein, e. 1941. Die Encrinurus- Arten des estlandischen Silurs. Geol. Inst. Univ. Tartu. 62, 49-77, pi. 1-4. salter, J. w. 1853. Figures and descriptions illustrative of British organic remains. Dec. VII. Mem. Geol. Surv. schmidt, f. 1859. Beitrag zur Geologie der Insel Gotland, nebst einigen Bemerkungen tiber die untersilurische Formation des Festlandes von Schweden und die Heimath der norddeutschen silurischen Geschiebe. Archiv Naturk. Liv-, Ehst- u. Kurl. 2, 403-64. 477 R. P. TRIPP: ENCRINURUS PUNCTATUS (WAHLENBERG) schmidt, f. 1881. Revision der ostbaltischen silurischen Trilobiten nebst geognostischer Ubersicht des ostbaltischen Silurgebiets, Abtheilung 1, Phacopiden, Cheiruriden und Encrinuriden. Acad. Imp. des Sci. St.-Pdtersbourg Mem. (7), 30, 1-237, pi. 1-14. temple, J. t. 1954. The Hypostome of Encrinurus variolaris and its Relation to the Cephalon. Geol. Mag. 91, 315-18. 1956. Notes on the Cheiruracea and Phacopacea. Ibid. 93, 418-30. tripp, r. p. 1957. The trilobite Encrinurus midtisegmentatus (Portlock) and allied Middle and Upper Ordovician species. Palaeontology, 1, 60-72, pi. 11, 12. and whittard, w. F. 1956. Proposed use of the plenary powers (a) to designate type species in harmony with accustomed usage for the genera ‘Encrinurus’ Emmrich, 1844, and ‘Odontochile’ Hawle and Corda, 1847 and (b) to validate the specific name ‘punctatus’ Wahlenberg, 1821, as published in the combination ‘Entomostracites punctatus’ (Class Trilobita). Bull. Zool. Nomencl. 12, 259-63, pi. 3. twenhofel, w. h. 1928. Geology of Anticosti Island. Geol. Surv. Canada, Mem. 154, 1-481, pi. 1-60. wahlenberg, G. 1821. Petrificata telluris Svecanae. Nova Acta Soc. Sci. Upsal. (5), 8, 1-116, pi. 1-4. whittard, w. f. 1938. The Upper Valentian Trilobite Fauna of Shropshire. Ann. Mag. nat. Hist. (11), 1, 85-140, pi. 2-5. R. P. TRIPP High Wood, Botsom Lane, West Kingsdown, Sevenoaks, Kent Manuscript received 20 September 1961 MICROPLANKTON FROM THE AMPTHILL CLAY OF MELTON, SOUTH YORKSHIRE by W. A. S. SARJEANT Abstract. Assemblages of organic-shelled microplankton from the Ampthill Clay (Upper Jurassic) of South Yorkshire are described. They comprise twenty-one species of dinoflagellates, of which two are new; twenty- seven species of hystrichospheres, of which three are new; and four species of presumed microplankton incertae sedis. From comparison with microplankton assemblages previously described, a stratigraphic position is tentatively assigned to the horizons studied. The assemblages of fossil microplankton to be described are from four horizons within the argillaceous facies of the Oxfordian (‘Ampthill Clay’) exposed in the clay pit of Messrs. G. and T. Earle, Ltd., at Melton, near Kingston-upon-Hull (grid reference S.E. 971268). A first visit was made to this pit during a meeting of the Yorkshire Geological Society on 13 February 1960, and a second visit in the following July, the pit having been considerably deepened between visits. At the time of the second visit, some 62 feet of grey clay were exposed below the unconformable capping of orange sands and Red Chalk (text-fig. 1). Four specimens collected were examined for microplankton, respectively from 61 ft. 7 in., 45 ft. approx., 25 ft., and 10 ft. below the overlying Cret- aceous beds (henceforth referred to as the ‘62-foot’, ‘45-foot’, ‘25-foot’, and TO-foot’ horizons). The samples^ consisted of light-grey clay with yellowish flecks. Each was crushed mechanically and treated successively with hydrochloric and hydrofluoric acids: the resultant organic residue was partially oxidized with Schulze solution and washed with potassium hydroxide solution, thus further concentrating the microfossil content. The product was mounted for study in glycerine jelly. The proportion of microfossils present proved high at all horizons, their state of preservation being generally excellent. Spores and pollen are present in abundance: at the 62-foot horizon they comprise only 40 per cent., at the 25-foot and 10-foot horizons around 50 per cent., and at the 45-foot horizon fully 70 per cent, of the total micro- fossil assemblage. Microplankton (dinoflagellates, hystrichospheres, and genera of presumed microplankton) form the remainder of the assemblage, foraminiferal shell linings being also present but only in extremely low numbers. DISCUSSION OF THE ASSEMBLAGES The relative proportions of the major microplankton groups are shown in Table 1, and especially noteworthy are the abundance of micrhystridia at the 25-foot horizon and the abundance of leiospheres at this and at the 45-foot horizons. In the assemblages as a whole, dinoflagellates form 42-5 percent., hystrichospheres 53-4 per cent., and genera incertae sedis 4 • 1 per cent. ; the dinoflagellates are numerically dominant only in the uppermost (10-foot) horizon. Twenty-one species of dinoflagellates, twenty-seven species of hystrichospheres, and four species incertae sedis were recognized; several [Palaeontology, Vol. 5, Part 3, 1962, pp. 478-97, pis. 69-70.] Hard band of calcareous nodules 25' Base not seen text- fig. 1. Section through the Ampthill Clay of Messrs. G. & T. Earle’s clay pit at Melton, near Hull. The horizons from which assemblages were examined are indicated by arrows. HOR 1 Z ONS °/o Dinof lagellotes °/o H y s t r I c 1 o s p her e s Microplank ton 1 nc ertae S « d i s Larger Forms M ic rhyst ridia L « iospheres T otal IO - Fool 5 3 • O 2 5-4 16-2 1 • 4 43-0 4-0 2 5 — Foot 39- 2 3-6 3 8-4 1 3-8 55-8 5-0 4 5 — Foot 40- 8 19-6 10-0 25- 6 55-2 4-0 62 — Foot 3 7 • 2 37-6 13-8 8-0 59-4 3- 4 table 1. The relative proportions of the groups of microplankton in the Melton assemblages. 480 PALAEONTOLOGY, VOLUME 5 other species of dinoflagellates are certainly present, each represented by a few poor specimens not suitable for full description. A list of species, with their numerical dis- tribution by horizon, is given in Table 2. In this section, only new species, or species about which additional information was forthcoming, are dealt with. All holotypes of species described are to be lodged in the Laboratory of Sedimentology, University of Reading. Class DINOPHYCEAE Order peridiniales Family gonyaulacidae Lindemann Genus gonyaulax Diesing Gonyaulax nealei sp. nov. Plate 69, fig. 1 ; text-fig. 2 Holotype. Ml 34/3/ 172, 62-foot horizon of Ampthill Clay, Melton. Dimensions of Type. Overall: length 69 p, breadth 61 p. Without spines: length 64 p, breadth 50^. Spines up to 5 p in length. Other specimens too damaged for satisfactory measurement. Diagnosis. A species of fossil Gonyaulax with epitheca conical, rounded at the apex, and hypotheca in the form of a truncated cone. Tabulation 6', la, 6", 6"', 2p, 1"": text-fig. 2. Gonyaulax nealei sp. nov. Holotype ( M 1 34/3/1 72), X 900. Left: in ventral view. Right: in dorsal view. ?./., transverse furrow. /./., longitudinal furrow. plate V" reduced and elongate. Sutures in the form of low ridges generally bearing simple spines of varying length and quite wide separation: the apical sutures, however, lack spines. Description. Theca pale yellowish in colour, thin walled and without granulation. There is no apical horn : the six apical plates differ from those of the rest of the theca in that W. A. S. SARJEANT: OXFORDIAN MICROPLANKTON 481 the sutures between them lack spines, whereas the sutures separating them from the other epithecal plates are spinose. One anterior intercalary plate and six pre-equatorial plates are present: plates 1" and 6" are somewhat reduced. The transverse furrow is of moderate breadth and extends round the theca in a laevo-rotatory spiral such that its two ends differ in antero-posterior position by twice the width of the furrow. The longitudinal furrow is narrow in its epithecal portion but broadens as it approaches the antapex. Of the six post-equatorial plates, plate V" is very reduced and not readily seen, and plates 2"' and 6'" are also somewhat reduced. Two large posterior intercalary plates are certainly present: a third (marked *?’) may also be present in the angle formed by plate lp against plate 2"' and the longitudinal furrow, but this could not be confirmed. The antapical plate is large and polygonal in shape. The species is named after Dr. J. W. Neale of the Geology Department, University of Hull. Remarks. Of the six specimens seen, only the holotype is well enough preserved to be capable of full study. In shape, tabulation, and ornamentation of crests, Gonyaulax rtealei differs from all described fossil species. Those most closely comparable are Gonyaulax cornigera Valensi 1953, from the Bathonian of France, and G. serrata Cookson and Eisenack 1958, from Upper Jurassic to ?Neocomian of Western Aus- tralia. In neither of these species is the tabulation fully known: the former is distin- guished by its longer and sometimes bifurcate sutural spines, the latter by the possession of grouped bifurcate processes on the apex. Gonyaulax paliuros Sarjeant 1962 Plate 69, fig. 2 Remarks. This species, originally described from the Oxfordian (Corallian) (Sandsfoot Clay, E. bimammatum Zone) of Dorset, is abundant at all four horizons. The tabulation proved, as always, very difficult to determine, but observations made supported the earlier interpretation. This species has also now been found present in the assemblage from the Hambleton Oolite of Filey Brigg, Yorkshire, described earlier (Sarjeant 19606). Gonyaulax eumorpha Cookson and Eisenack 1960 Plate 69, fig. 12; text-fig. 3 Remarks. This species, originally described from Oxfordian to Lower Kimmeridgian and probably Tithonian horizons of Western Australia, is recorded for the first time from Europe, representatives being present at three of the horizons studied. The figured specimen (Ml 32/8/61 a) is the best preserved. Its tabulation corresponds in broad terms to that of the type; there are, however, several differences in detail. The boundary between plates la and 6" is well defined and plate 6" is clearly larger than plate la: in the type, the boundary is poorly defined and plate la considered larger. The transverse furrow shows a distinct subdivision by low sutures, a feature not observed in the type: and the posterior ventral plate (p.v.) is squarish and has a clearer relation to the antapical plate. Pre-equatorial plate 3" is torn open and may well represent an archaeopyle. 482 PALAEONTOLOGY, VOLUME 5 text-fig. 3. Gonyaulax eumorpha Cookson and Eisenack. The specimen figured (M132/8/61a) differs from the type description in detail of tabulation. Left: in ventral view. Right: in dorsal view, x 600. text-fig. 4. Gonyaulax nuciformis (Deflandre) comb. nov. Ventral tabulation (left) from specimen Ml 34/ 1/37; dorsal tabulation (right) diagrammatic, reconstructed from several specimens studied. x 600. Gonyaulax nuciformis (Deflandre) comb. nov. Plate 69, fig. 6; text-fig. 4 1938 Palaeoperidinium nuciforme Deflandre, p. 180, pi. viii, figs. 4-6. Diagnosis. A species of fossil Gonyaulax having a spheroidal to ovoidal theca, thick walled and very coarsely granular, the granules in some cases so large as to be better regarded as very short spines. Tabulation ?4', la, 6", 6"', lp, V": extremely difficult to determine, since the sutural crests are very low and masked by the surface ornament. The apical process is short and broad, bifurcating briefly distally and giving rise to a short terminal process. Remarks. This species was originally attributed to the genus Palaeoperidinium in absence of knowledge of the tabulation. In course of a recent visit to the Laboratoire de Micropaleontologie in Paris, I was courteously allowed by Prof. Deflandre to examine the holotype, which gives indication of a tabulation but no more. The species is present in the Middle Callovian of Dorset (Sarjeant 1962) and it occurs at all four Melton Horizon within the Ampthill Clay ^\o f Melton Species of microplankton 6 2 — foot M 1 34 o o T ^ 2 5 — f o o f M 1 33 1 O — f oof M 132 Gonyaulax iurassica Deflandrc 3 1 1 7 1 6 49 G cladophora Deflandre 3 1 3 1 7 49 G eisenacki Deflandre 1 5 1 1 4 9 G. ambiqua Deflandre 4 5 9 7 G- paliuros Sarjeant 19 9 29 1 2 G. acanthosphaera Sarjeant 9 — 1 I 1 4 G eumorpha Cookson & Eisenack 4 3 — 3 G. nuciformis (Deflandre") comb. nov. 2 5 9 2 1 8 G. pachyderma Deflandre 2 — — — Horizon within slhc Anplhlll Cloy b2 — foot M 1 34 o T - in ^ 2 5 — f o o f M 133 0 ° rsi 1 - o z Gonyoulox lurottlco Dcflandrc 3 1 1 7 1 6 49 G clodophoro Dcflandrc 3 1 3 1 7 49 G. cltcnocki Dcflandrc 1 5 1 1 4 9 G. ombiqua Dcflandrc 4 5 9 7 G poliuros Sarjcanl 19 9 29 1 2 G. acanthotphacra Sarj.ant 9 — 1 1 14 G cumorpho Cookson & Eiscnack 4 3 — 3 G. nuclformlt (Ocflandrc) comb. nov. 25 9 2 18 G. oochydcrmo Dcflandrc 2 — — — G ncolci tp. nov. 1 5 — — Pluriar*ollum oiminatonente Soricant — — 1 — Clcnldodinlum ornofum Dcflandrc 1 2 — 1 Cf Palac.ohy.trichophoro splnotl.timo (Dcfl) 1 — — — pprcodinln Dcflandrc 1 2 2 1 1 2 9 Scriniodlnlura crytlalinum (Dcflandrc) 1 2 1 4 35 75 S. luridum Dcflandrc 2 1 1 3 7 S. aoltrifum Dcflondrc 3 1 3 9 — S. tubvallore Sarlcant 3 7 — — S. oxfordianum sp. noy. — 7 5 2 S. dictyolum Cookson & Eiscnack 6 12 4 IO Nqnnoarqtopdi_p.lLuclda Dcflandrc 3 18 — 1 Hystrlchosphacra furcata (Ehrcnbcra) — 2 — — Hysirlchosohacrldlum talplnaophorum (Dcfl) 2 7 — — Boltlsphacridium pllotum (Ehrenbcro) 5 1 8 — 1 1 8. stlmullfcrum (Dcflandrc) 47 3 1 O 19 B. vctlitum (Dcflandrc) 23 1 2 1 34 B. chrcnbcrai (Dcflandrc) 19 1 5 — 1 1 B Irlbullfcrum so. nov. 3 4 — 6 B polvfrichum (Valenti) 5 1 5 — — B. pgryltplnum (Dcflandrc) — — — 4 BoltitPhocrldium tp. 1 — — — Cannospjja^psis caullcryl Dcflandrc 2 2 3 1 1 4 Sy ttematophoro orbifera Klcment 1 1 — — Oiclyopyxlt orcolafo Cookson l El scnock 2 3 — — Chlomydophorcllo wallolo Cookson BEIscn- — — — 4 Cymotiospbocro pqrvq Sarjcanl — — 3 2 Ptcrosocrmopsi the Hot Sorjcant — 1 2 8 P cf. hcliot Sarlcant — — — 1 Mierhystridlum inconsplcuum (Dcflandrc) 1 7 30 114 62 M fragile Dcflandrc 3 3 1 4 1 4 8 M — Valenti 7 5 ? — M. itcllatum Dcflandrc 8 1 — 4 M rhopali cum tp. nov. 2 ? 6 9 M. rorltplnum Sarjeant — 2 1 9 — M. t y d u t Valenti — — IO — M. cf plvctco*! Valenti 1 — — — M dcflandrcl Valenti — — 3 — Lclotohacrldia tlmlllt Cookton 1 Eltcnack — — 6 4 L chytrocldct tp. nov. 40 128 3 2 3 1- »P — — 2 5 — Palacostomocyttlt tlnuota Cook. & Elt. 2 Stcphonclyfron teorburohente Sarjeant 7 4 1 1 L Sorjcant 7 7 2 1 20 Nclrclylron itcaoitum Sarjcanl 6 IO — 3 table 2. List of microplankton species present in the Melton assemblages, showing numerical distribution by horizon. table 3. Known distribution by horizon of microplankton species in British Callovian and Oxfordian assemblages described to date, compared with the known distribution of these species at other localities and horizons. (Distribution of species in the Bajocian and Bathonian of France based on Deflandre 1947, Valensi 1953; in the Oxfordian and L. Kimmeridgian of France, on Deflandre 1938, 1941 ; in the German Malm, on Klement 1960: in the Upper Jurassic of Australasia, on Cookson and Eisenack 1958, 1960: in the Upper Kimmeridgian of England, on Downie 1957: and in post-Kimmeridgian sediments, on Deflandre 1934, 1937, O. Wetzel 1933, &c.) W. A. S. SARJEANT: OXFORDIAN MICROPLANKTON 483 horizons: the majority of its representatives, like the type, show only traces of a tabula- tion, the thick walls, dark yellowish-brown colour and heavy granulation making study difficult. One specimen, however (Ml 34/1/37), in which the dorsal surface is almost entirely lacking, allowed determination of details of the ventral tabulation, and indica- tions on several other specimens enabled reconstruction of the dorsal tabulation. The species is clearly attributable to the genus Gonyaulax and resembles, in tabulation, the thickness and granular nature of its walls, and the possession of a short apical horn, the species G. pachyderma Deflandre of the French Lower Oxfordian (1938), differing from the latter in the shape of the apical horn, details of plate shape, and the presence of an anterior intercalary plate. A close systematic relationship between the two species is clearly indicated ; G. nuciformis is known to occur earlier than G. pachyderma and might be visualized as giving rise to the latter species by loss of plate la, simplification of horn structure and emphasis of sutural crests. However, no intermediate forms are known to date. The range of dimensions exhibited (Melton specimens) is overall length 56-58 p, breadth 50-64 p : the specimens are more generally spheroidal than those whose dimen- sions are quoted by Deflandre (length 60-65 p: breadth 47-53 p). Family hystrichodinidae Genus palaeohystrichophora Deflandre, 1934 (emend. Deflandre and Cookson, 1955) Cf. Palaeohystrichophora spinosissima (Deflandre 1938) Remarks. A single specimen from the 62-foot horizon accords well with forms de- scribed under this name from North Yorkshire (Sarjeant 1960). The tabulation again proved incapable of determination. ? Order gymnodiniales Family uncertain Genus pareodinia Deflandre Pareodinia ceratophora Deflandre, 1947 Plate 69, fig. 8 ; text-fig. 5 Remarks. This species was originally described from the Callovian of the Baltic region and Bajocian of France (1947). It has subsequently been found represented, in its typical form, in British strata ranging in age from Middle Callovian to Upper Oxfordian (Lantz 1958, Sarjeant 1960, 1961, 1962) and a variety, P. ceratophora var. pachyceras Sarjeant, in the Lower Callovian and lowest Oxfordian (1959 and 1961). This species is of extremely variable form, variation occurring in overall size, in granularity, in ratio of length to breadth, in shape of the apical horn, and in ratio of horn length to overall length. The variation in all characters save granularity is shown in text-fig. 5, where the outlines of individuals, drawn to a constant scale, are shown in pictogram form (variation in granularity proved independent of these dimensional variations). All intermediates between the figured extremes are known. Within the Melton assemblage, a very wide variation of form was observed, the variations typified by specimens in text-fig. 5 b, c, being especially frequent. The latter is indistinguishable in outline from the forms classed previously (1959) as var. pachyceras, differing only in i i C 674 484 PALAEONTOLOGY, VOLUME 5 the less strongly coloured and more granular nature of the shell. Pareodinia aphelia Cookson and Eisenack 1958, from the Upper Jurassic and Lower Cretaceous of Western Australia, is known to vary in proportions in similar fashion to P. ceratophora , al- though the proportion of horn length to body length is generally smaller. It is probable text-fig. 5. The range of variation exhibited by Pareodinia ceratophora Deflandre. Outlines of speci- mens from several horizons, drawn to a constant scale, a, CB8 1/6/4, from the Oxford Clay of Cay ton Bay, Yorkshire, b, c,f M134/1/92, M133/4/14, and M134/4/66, from the Ampthill Clay of Melton. d, e, WC90/14/5 and WC90/1/1, from the Oxford Clay of Chickerell, Dorset, g, 0130/9/2, from the Osmington Oolite of Osmington Mills, Dorset. All x 375. EXPLANATION OF PLATE 69 Microplankton from the Ampthill Clay of Melton, near Hull, Yorkshire. All figures xc. 500. 1, Gonyaulax nealei sp. nov., M134/3/172, holotype, ventral view. 2, G. paliuros Sarjeant, M133/2/24, ventral view. 3, G. eisenacki Deflandre, Ml 34/1/71, lateral view. 4, Pluriarvalium osmingtonense Sarjeant, M 1 33/5/13, dorsal view. 5, Scriniodinium subvallare Sarjeant, M134/3/132, ventral view. 6, G. nuciformis (Deflandre) comb, nov., M134/1/37, ventral view (interior view of half-shell). 7, S. luridum (Deflandre), M 1 34/2/1 3 1 . 8, Pareodinia ceratophora Deflandre, M134/1/92. 9, 10, Nan- noceratopsis pellucida Deflandre, M132/8/18a, M134/4/64. 11, S. dictyotum Cookson and Eisenack, M132/8/88a. 12, G. eumorpha Cookson and Eisenack, M132/8/61a. 13, 14, S. oxfordianum sp. nov. 13, M 131/1/58. 14, holotype, FB122/1 1/34 Hambleton Oolite, Carr Naze, Filey Brigg, Yorks. Palaeontology, Vol. 5 PLATE 69 SARJEANT, Oxfordian microplankton W. A. S. SARJEANT: OXFORDIAN MICROPLANKTON 485 that both species are part of one continuous plexus and that the systematic distinction between them is wholly artificial. Order Uncertain Family deflandreidae Genus scriniodinium Klement Subgenus endoscrinium Klement 1960 Scriniodinium (? Endoscrinium) oxfordianum sp. nov. Plate 69, figs. 13, 14 1960 Scriniodinium sp. A Sarjeant, p. 394, pi. 13, fig. 2. 1962 Scriniodinium (? Endoscrinium ) sp. Sarjeant, p. 263, pi. 1, fig. 15. Holotype. FB122/1 1/34, Hambleton Oolite (10 feet below top), Carr Naze, Filey Brigg. Dimensions of type. Cyst length 100 p, breadth 82 p. Theca length 82 p, breadth 62 p. Diagnosis. A species of Scriniodinium having a cyst of broadly ellipsoidal shape, one face of whose hypothecal portion is somewhat flattened. Theca ellipsoidal, having a distinct tabulation, apparently 4', 6", 5"', Op, 0""; the sutures of the ventral surface are unornamented, but sutures elsewhere bear raised crests formed by short spines, quite widely separated, whose tips are linked by a trabecula following the course of the suture. Description. The cyst is ellipsoidal, pale yellowish or yellowish-brown in colour, smooth or very faintly granular. In some specimens there is a distinct equatorial bulge, the shape thus becoming biconical rather than ellipsoidal; in others, the space between theca and cyst is larger at one pole than at the other. The theca is somewhat darker in colour and broadly ellipsoidal in shape. Its surface may be areolate in patches; these patches are quite irregular in position and their distribution varies between individuals, the areola- tion being in all cases most pronounced near to a suture and dying out toward the centre of the plate. The characteristic features of this species are its distinctive sutural crests, composed of widely spaced spines linked in T-fashion by a trabecula. The sutures of the ventral surface lack such crests, being marked only by low ridges, extremely hard to see even under the most favourable conditions: orientation and the establishment of a tabulation are thus difficult. From the examination of all available specimens, the tabulation was considered to resemble that established by Klement for his subgenus Endoscrinium , with four apical plates definitely present. The transverse furrow is of moderate breadth and only feebly laevo-rotatory, the longitudinal furrow narrow in its epithecal portion but broadening as it approaches the antapex. All specimens examined show some degree of damage, but the presence in constant position of an archaeopyle cannot be affirmed. Remarks. Following study of the Melton specimens of Scriniodinium oxfordianum, representatives of this genus in the Yorkshire Coraflian horizons were re-examined and the earlier interpretation of the crests of Scriniodinium sp. A (1960) corrected: these are as here described, and not ‘perforated and in part areolate’, as stated earlier. Indeed, specimen FB122/11/34 shows the form of the crests more clearly than any other seen; 486 PALAEONTOLOGY, VOLUME 5 for this reason, it has been chosen as type despite its damaged condition. The specimens from the Ringstead Waxy Clay (E. bimammatum Zone) of Dorset, earlier attributed to an undescribed species of Scriniodinium (1962), fall clearly within the range of variation of this species. The Melton specimens are generally somewhat larger than the type; specimen M131/1/58 (figured) has cyst 124 p, x 107-5 ^ and theca 98-5 p. x 75-5 p. Scriniodinium oxfordianum may represent an intermediate stage between species without a recognizable tabulation, such as the type species of the genus, Scriniodinium (S'.) crystallinum (Deflandre) and clearly tabulate species, such as S. ( Endoscrinium ) luridum. In S. oxfordianum , the sutures of the ventral surface are poorly defined; in S. crystallinum, the transverse furrow cannot be traced across this surface and no longi- tudinal furrow is apparent. The flattening of one face of the hypothecal portion of the cyst of S. oxfordianum may be regarded as an approach to the projecting membraneous ‘cross-arching" of S. luridum: and the tabulation of the two species appears similar. In some poorly preserved specimens from Melton, there appears to be incomplete development of crests on sutures near the apex; these specimens could not be definitely attributed either to >S. crystallinum or to £. oxfordianum and may well represent an in- termediate stage of progressive crest development, leading from the former to the latter species. A process of filling in of the crests and modification of general shape might lead from S. oxfordianum to S. luridum. The forms from the Upper Calcareous Grit of Yorkshire, described as Scriniodinium sp. B (19606) are similar in general shape to S. luridum but have crests of the type of S. oxfordianum : however, they occur in an assemblage in which the typical forms of these species are not present. Apparent intermediates of this character are not known from earlier horizons, and this second line of possible evolutionary development remains hypothetical. Order hystrichosphaeridia Family hystrichosphaeridae Genus hystrichosphaera O. Wetzel 1933 Hystrichosphaera furcata (Ehrenberg 1838) O. Wetzel 1933 Remarks. The occurrences of this species in the Upper Jurassic, of which the Melton record is the third, are of interest in relation to the controversy with regard to the definition of this species and of El. ramosa (Ehrenberg 1838) O. Wetzel 1933. In the Upper Cretaceous, the two species form a continuously varying plexus (Lejeune- Carpentier 1937 a, b ); El. ramosa has not to date been recorded earlier. It appears that H. furcata is, as would be expected, the ancestral type and that the trend of increase in complexity of the spines, leading to H. ramosa, did not begin to operate until well into the Cretaceous. Genus baltisphaeridium Eisenack 1958 Baltisphaeridium ehrenbergi (Deflandre 1947) Sarjeant 1961 Plate 70, fig. 1 ; text-fig. 6a Remarks. This species, originally described from the Lower Oxfordian of Normandy, is present in three Melton assemblages. It has also now been noted from three horizons in the Yorkshire Oxford Clay (from the base, in the exposures in Scarborough Castle W. A. S. SARJEANT: OXFORDIAN MICROPLANKTON 487 Cliff: and from horizons respectively 25 feet and c. 100 feet above the base, in High Red Cliff, Cayton Bay; all within the Q. mariae Zone) and from the Hambleton Oolite of Filey Brigg, Yorkshire (C. cor datum Zone). These are the first British records of this species. Baltisphaeridium polytrichum (Valensi 1947) Sarjeant 1960a Plate 70, fig. 2; text-figs. 6b Remarks. This species, originally described from the Bathonian of France, is present in the two lower Melton horizons and is also present in the Yorkshire Oxford Clay (lowest and 25-foot horizons: see above) and in the Osmington Oolite of Filey Brigg, Yorkshire (P. plicatilis Zone). These occurrences represent a considerable extension of the known range of this species within the Jurassic. A morphologically similar form from the Australian Upper Cretaceous has been placed in this species (Deflandre and Cookson 1955), but the stratigraphic separation remains immense. The forms from the Upper Kimmeridgian of Dorset, attributed to this species by Downie (1957), show clear morphological differences (Sarjeant 1960a). text-fig. 6. Hystrichospheres from the Ampthill Clay, a, Baltisphaeridium ehrenbergi (Deflandre) (M134/4/60). b. B. polytrichum (Valensi) (M134/3/67). c, B. tribuliferum sp. nov. Holotype, Ml 34/2/29. All x900. V A JL text-fig. 7. Variation in the form of spines of Baltisphaeridium tribuliferum sp. nov. Holotype, Ml 34/2/29; Xc. 1,800. Baltisphaeridium tribuliferum sp. nov. Plate 70, fig. 4; text-figs. 6c, 7 Holotype. Ml 34/2/29, 62-foot horizon of Ampthill Clay, Melton. Dimensions of type. Overall: long diameter 59 p, short diameter 54 p. Shell: long diameter 33 p , short diameter 25-5 p. Range of dimensions. Overall: long diameters 53-62 p, short diameters 48-58 p. Diagnosis. A species of Baltisphaeridium having an ovoid shell bearing widely spaced processes, attached proximally by root-like extensions on the shell surface and tapering somewhat distally, branching at a constant distance from the shell surface into bi-, tri-, or quadri-furcations of variable length and attitude. Description. Shell smooth, without granulation or punctation, varying in hue from 488 PALAEONTOLOGY, VOLUME 5 yellowish to quite colourless. The spines are hollow but appear not to open directly into the shell's interior. They are of very variable form, never simple but having two to four branches of varying length: the branches appear flexible and may be directed outward from, or inward towards, the shell surface or may be roughly parallel to it (text-fig. 7). The branches are closed at their tips. The spines are widely spaced: the number present is between about forty-five and sixty; in length they exceed half the long diameter. Remarks. Baltisphaeridium tribuliferum differs from all described species of this genus in its combination of form, and proportionate length, of processes with shell shape. The forms from the Lower Oxfordian of France, described by Deflandre as Hyst- richosphaeridium cf. intermedium (1938), are probably attributable to this species, as also is the form from the Bathonian of France, described under this name by Valensi (1953). This species is present in low numbers at three Melton horizons and has also been noted from all three horizons of the Yorkshire Oxford Clay (see above) and from the Lower Calcareous Grit and Hambleton Oolite of Filey Brigg, Yorkshire. Baltisphaeridium parvispinum (Deflandre 1937) Cookson and Eisenack 1957 Text-fig. 9 d Remarks. This species, present at the 10-foot Melton horizon, is described for the first time from Britain and from the Jurassic: it has previously been recorded from the Lower Cretaceous (Aptian) of France (1937), Queensland, and Papua (Aptian: Cookson and Eisenack 1957) and the Upper Cretaceous of Belgium (Conrad 1941). In their dimensions, the Melton specimens fall between the range estimated by Cookson and Eisenack for the French specimens (shell 40 p x 20 p) and that quoted for the Austral- asian specimens (shell 73-76 p x 32-33 p); specimen M132/10/1 is typical — overall 63 p x 38 p, shell 57-5 p x 32-5 p. Baltisphaeridium stimuliferum (Deflandre 1938) Sarjeant 1961 Plate 70, figs. 5, 17; text-figs. 8?c, e, g Remarks. The range of forms depicted in text-fig. 8, all from the lowest (62-foot) horizon at Melton, well illustrates the difficulty of establishing a satisfactory morpholo- EXPLANATION OF PLATE 70 Microplankton from the Ampthill Clay of Melton, near Hull, Yorkshire. All figures (except fig. 12) xc. 500; fig. 12, Xc. 750. 1, Baltisphaeridium ehrenbergi Deflandre, Ml 34/4/60. 2, B. polytrichum (Valensi), Ml 34/3/67. 3, Cannosphaeropsis caulleryi (Deflandre), Ml 34/4/25. 4, B. tribuliferum sp. nov., Holotype, Ml 34/2/29. 5, B. stimuliferum (Deflandre), Ml 34/2/42. 6, Micrhystridium fragile Deflandre, Ml 34/1/72. 7, B. pilosum (Ehrenberg) with Stephanelytron redcliffense Sarjeant, M132/8/105a and IVI 132/8/105. 8, B. sp., M134/3/73. 9, Leiosphaeridia similis Cookson and Eisenack, M133/7/48. 10, B. pilosum (Ehren- berg), M134/4/26. 11, Stephanelytron scarburghense Sarjeant, M134/2/104. 12, S. redcliffense Sarjeant, Ml 34/4/16, in slightly oblique view, showing the matte of fibres within the corona. 13, Leiosphaeridia chytroeides sp. nov., holotype. Ml 33/2/53. 14, M. rhopalicum sp. nov., holotype, Ml 32/8/47. 15, Pterospermopsis cf. helios Sarjeant, Ml 32/9/27. 16, L. chytroeides sp. nov., Ml 34 2/80, showing organism emerging from cyst. 17, B. stimuliferum (Deflandre), M134/2/92. 18, Netrelytron stegastum Sarjeant, M132/5/2. 19, Dictyopyxis areolata Cookson and Eisenack, M134/4/16. Palaeontology, Vol. 5 PLATE 70 • ■. 'i , SARJEANT, Oxfordian microplankton 489 W. A. S. SARJEANT: OXFORDIAN MICROPLANKTON gical classification of those hystrichospheres with a spherical test and with simple spines present in moderate number. The size ranges of these forms overlap from above and below the artificial boundary (‘size generally less than 20 p) separating Micrhy- stridium from Baltisphaeridium-, and considerable variation in spine number and length is exhibited. Specimens e and g (text-fig. 8), in size and in spine number and character, are attributable to Baltisphaeridium stimuliferum, which has a quoted range of shell diameters 20-26 p and of spine lengths 10-23 p (Deflandre 1938, Valensi 1953). Speci- men a is clearly Micrhystridium fragile. Its author, Deflandre (1947), quotes for this species a range of overall diameters of diameters of 10-21 p. Baltisphaeridium stimuliferum typically has about 1 5 spines ; Micrhystridium fragile, 9 to 26; and M. recurvation, 20 to 30. In known chrono- h logic range, these species again overlap. B. TEXT.FI0.8.HystrichospheresofcloseIycomparable stimuliferum has been recorded from the Structure from the lowest (62-foot) Melton horizon. Bajocian, Bathonian, and Lower Oxfordian a, Micrhystridium fragile Deflandre (Ml 34/1/72). of France (Valensi 1953, Deflandre 1938) h, f M. recurvatum Valensi (M134/1/8 and 1962). M. fragile has been recorded from the Bajocian and Bathonian of France (Deflandre 1947, Valensi 1953) and from the 1959, 19606, 1961, 1962). M. recurvatum and its varieties have been recorded from the Bajocian and Bathonian of France (Valensi 1953) and from the Lower Callovian and Lower and Upper Oxfordian of England (Sarjeant 19606, 1961, 1962). At many horizons, the hystrichospheres of this general morphological type (shell spherical, spines not exceeding thirty in number, spine lengths from about one-quarter of the shell diameter to slightly greater than the diameter, shell diameter between 8 p and 40 p) may be grouped without difficulty into one or more of the above species. Of the Melton assemblages, only that from the 62-foot horizon presented any difficulties : it is significant that hystrichospheres of the specified morphological type were com- monest at this horizon. Specimen d is near the limit of spine number but may be classed as M. fragile; specimen c is morphologically most similar to B. stimuliferum but has too many spines. 12-24 p, and shell diameters of 8-10 p. Valensi (1953) quotes ranges respectively of 15-40 p and of 7-20 p \ a similar range was exhibited by an assemblage studied earlier from the Yorkshire Hambleton Oolite (Sarjeant 19606). Specimens 6 and / fall within the species Micrhystridium recurvatum Valensi (1953), which, with its described varieties, exhibits a range of overall diameters of 1 7—35 p and shell classed as B. cf. stimuliferum (Sarjeant Deflandre (Ml 34/3/17). xc. 750. Lower and Middle Callovian and the Lower and Upper Oxfordian of England (Sarjeant 490 PALAEONTOLOGY, VOLUME 5 Although the size boundary separating Micrhystridium and Baltisphaeridium is arbitrarily drawn, these genera appear nonetheless to express natural morphogenetic groupings and problems in allocation are rare. The mean and modal sizes of the three species here discussed fall clearly above or below the boundary; however, their very similar morphology suggests a relationship. M. fragile and M. recurvation appear to be two parts of a single morphological plexus; and the degree of variation within the species B. stimuliferum is comparable. Baltisphaeridium sp. Plate 70, fig. 8 ; text-fig. 9c Specimen. M134/3/73, 62-foot horizon of Ampthill Clay, Melton. Dimensions. Overall: long diameter 62 p, short diameter 60 p. Shell: long diameter 32-5 p, short diameter 25 p. Description. Shell oval, bearing simple, hollow spines; these open directly into the shell interior and have closed tips. The length of the spines exceeds half the long diameter of the shell; they number around thirty. Remarks. The single specimen differs in its morphology from all described species. In view of lack of knowledge of the range of variation, it was decided not to designate this as a new species. Genus systematophora Klement 1960 Systematophora orbifera Klement 1960 Remarks. The two specimens from Melton, placed within this genus and species, are both severely obscured by adherent organic debris, so that their attribution here, made on the basis of what could be seen of the process clusters, is somewhat doubtful. Genus micrhystridium Deflandre 1937 Remarks. The validity of this genus, as at present defined, is discussed above (see under Baltisphaeridium stimuliferum). Micrhystridium rhopalicum sp. nov. Plate 70, fig. 14; text-fig. 9/ Holotype. Ml 32/8/47, 10-foot horizon of Ampthill Clay, Melton. Dimensions of type. Overall diameter 21^,: diameter of shell 13-5/a: spines c. 4 p in length. Range of dimensions. Overall diameter 18-23 p: shell 10-15 p. Diagnosis. A species of Micrhystridium having a spherical shell, without surface orna- mentation. Spines relatively few in number, short (less than half the shell diameter), with knob-shaped or briefly bifurcate tips. Description. Shell yellowish in colour and of moderate thickness. The spines number 15-20: they taper from the base, but swell out at the tip in club-like form or into a T-shape with very brief arms. W. A. S. SARJEANT: OXFORDIAN MICROPLANKTON 491 Remarks. This species, present probably at all four Melton horizons, is also represented in an assemblage from the Osmington Oolite of Filey Brigg and may well have a much wider distribution than is at present known. However, at the high magnifications neces- sary for study of the processes, it has frequently proved difficult to confirm that the spines having a knobbed appearance are not merely recurved simple spines ; at several horizons, more information must be awaited before its presence can be confirmed. f 9 text-fig. 9. Hystrichospheres from the Ampthill Clay. a, Pterospermopsis helios Sarjeant ( M 1 32/7/ 14). b, P. cf. helios Sarjeant (Ml 32/9/27). c, Baltisphaeridium sp. (M134/3/73). d, B. parvispimwiDeftandre (Ml 32/10/1). e, Micrlnystridium deflcmdrei Valensi (M133/3/23). /, M. rhopalicum sp. nov. (Holotype, Ml 32/8/47). g, M. rarispinum Sarjeant (Ml 33/2/25). X c. 750. In the form and number of its processes, Micrhystridium rhopalicum differs from all described fossil species of this genus. The only comparable species is M. bigoti, from the Bajocian and Bathonian of France (Deflandre 1947); however, in this latter species^the processes are clearly capitate and are much shorter and more numerous. Micrhystridium cf. piveteaui Valensi 1953 Specimen. Ml 34/3/1 7, 62-foot horizon of Ampthill Clay, Melton. Dimensions. Overall: long diameter 36 p, short diameter 27 p. Shell: long diameter 21-5 p, short diameter 16 p. Spines c. 9 p long. 492 PALAEONTOLOGY, VOLUME 5 Description. Shell ovoidal, yellowish, bearing a large number (50-60) of simple processes whose length is equal to about half the long diameter. The surface of the shell lacks other ornament. Remarks. The single specimen here described differs in shell shape and process number from all described species. It finds its closest comparison in Micrhystridium piveteaui, which has, however, somewhat fewer processes (about 40). In general morphology, there is considerable similarity to the B. stimuliferum — M. fragile — M. recurvatum type ; but specimens of intermediate character were not found. Family pterospermopsidae Genus pterospermopsis W. Wetzel 1952 Pterospermopsis cf. helios Sarjeant 1959 Plate 70, fig. 15; text-fig. 9b Specimen. Ml 32/9/27, 10-foot horizons of Ampthill Clay, Melton. Dimensions. Overall: long diameter 29 p, short diameter 23 p. Capsule: maximum diameter 9 p. Description. Capsule broadly oval, almost spherical, in outline: colour yellowish-brown. Wing oval in outline, thrown into nine radial folds; colour pale yellowish. Ratio of wing breadth to capsule radius: 2+ to 1. Remarks. This species is closely comparable to forms present in the Hambleton Oolite of Filey Brigg, Yorkshire (Sarjeant 19606). In wing outline and in ratio of wing breadth to capsule radius, it differs from the typical P. helios, specimens of which are present at three Melton horizons. (P. helios typically has a wing circular in outline and a ratio of 1-5 to 1.) Family leiosphaerididae Eisenack Genus leiosphaeridia Eisenack 1958 Subgenus leiosphaeridia subgen. nov. Type species. Leiosphaeridia (L.) baltica Eisenack 1958. Diagnosis. A subgenus of Leiosphaeridia comprising species having a circular pylome or none at all. Leiosphaeridia ( Leiosphaeridia ) cf. similis Cookson and Eisenack 1960 Plate 70, fig. 9; text-fig. 10 Remarks. Ten specimens in the two upper Melton horizons correspond in their morph- ology to this species, originally described from probably Tithonian and late Upper Jurassic horizons of Western Australia and Papua. They differ however in their much smaller size; the range of diameters is 38-45-5 p, in comparison with a quoted range of 70-100 p. Subgenus chytroeisphaeridia subgen. nov. Type species. Leiosphaeridia ( Chytr .) chytroeides sp. nov. Diagnosis. A subgenus of Leiosphaeridia comprising species having a polygonal or W. A. S. SARJEANT: OXFORDIAN MICROPLANKTON 493 subpolygonal pylome, lateral or terminal in position. The pylome may not be present in all individuals of such species. Remarks. Evitt (1961), discussing the significance of the pylome in fossil dinoflagellates and related organisms, proposed the term ‘archaeopyle’ for pylomes formed by the release of single plates or groups of plates. He lists Leiosphaeridia as a genus without definite dinoflagellate affinity, in which the pylome is most often absent or, where present, is of circular shape. The form of the pylome in L. chytroeides sp. nov. suggests an archaeopyle and thus also suggests dinoflagellate affinity; a taxonomic distinction from species having a circular pylome or no pylome is thus necessary. However, since a pylome is not constantly present, differentiation is not always possible. It is therefore considered best that all forms conforming in their morphology with Eisenack’s generic diagnosis should remain in Leiosphaeridia and that distinction on pylome form should be made at subgeneric level only, the two subgenera being otherwise morphologically indistinguishable. a b text-fig. 10. Leiosphaeridia similis Cookson and Eisenack. Specimens showing extremes of the size range exhibited in the Melton assemblages, a. Ml 33/7/48 (45-5/z). b, M 133/8/26 (34 p). xc. 750. text-fig. 11. The range of variation exhibited by Leiosphaeridia chytroeides, sp. nov. a , M 1 33/8/5 1 . b, M131/2/19. c, M 1 34/3/1 8. d, Holotype, M133/2/52. R 7-5 0-4 0-75 0-9 0-65 0-95 0-95 2-9 15 124 6. SM. A51420 F 110 0-45 0-9 0-85 1-15 14 12 7. SM. A51421 |R 6-5 0-4 0-8 0-9 0-65 0-85 30 13 12 Form C 1. SM. A51003 F 43 0-4 0-8 1-2 0-65 11 70.9 4-1 10 9 2. SM. A51422 F 12 0-45 0-75 09 70.8 711 70-9 73-8 9 3. SM. A51423 F 10 0-4 0-7 0-8 0-8 1-2 4-2 13 10 4. SM. A51424 F 8 0-45 0-75 10 0-65 1-0 709 3-6 13 c.10 5. SM. A51425 F 8 0-35 0-6 0-7 0-75 1-25 10 4-8 10 7 6. SM. A51426 F 12 0-4 0-55 0-8 4-4 8 7. Scot. Sur. F 18 0-5 09 1-3 0-7 10 4-4 11 9 H1615 8. BM (NH) F 5-5 06 ?1T 711 0-5 + 0-85 + 3-6 12 c. 9 24953 Remarks. The other two long subspecies of G. tamariscus are G. tamariscus linearis and G. tamariscus distans. Both are essentially parallel-sided, but G. tamariscus linearis is rather broader than G. tamariscus tamariscus , tapering suddenly in the proximal end. G. tamariscus distans has smaller excavations and longer supragenicular walls than the typical form. Glyptograptus tamariscus linearis Perner Plate 72, fig. 8; text-fig. lv 71868 Diplograpsus tamariscus Nicholson, p. 526, pi. 19, fig. 13 ( non figs. 10-12). 71876 Diplograptus tamariscus Nicholson; Lapworth, pi. 2, fig. 34. 71877 Diplograptus tamariscus Nicholson; Lapworth, pi. 6, fig. 12. 71897 Diplograptus tamariscus Nicholson; Tornquist, p. 15, pi. 11, figs. 15-19. 1897 Diplograptus tamariscus linearis Perner, p. 4, text-fig. 2 (7 pi. 9, fig. 23). 1907 Diplograptus ( Glyptograptus ) tamariscus Nicholson; Elies and Wood (pars), p. 247, pi. 30, fig. 8c (non text-figs. 161 a-d, pi. 30, figs, a, b, d). Lectotype. Specimen figured by Perner (1897) as G. tamariscus linearis (text-fig. 2) was designated lectotype by Pfibyl (1948); it is from the zone of Monograptus convolutus. Number of specimens. One (the specimen figured by Elies and Wood, pi. 30, fig. 8c). Birmingham Univ. \212. Horizon and locality. Dobb’s Linn. Probably the zone of M. cyphus (Orthograptus mutabilis, cf. Dimorphograptus decussatus and monograptid fragments on the same slab). G. H. PACKHAM: BRITISH SILURIAN DIPLOGRAPTIDS 507 Revised diagnosis. Long, broad, parallel-sided, width almost constant beyond the first few millimetres, excavations deep. Description. The only specimen available is preserved flattened, it has a length of 34-5 mm. and reaches a maximum width of 1-5 mm. The rhabdosome is slightly tapering, but is essentially parallel-sided. The width at the first pair of thecae is 0-7 mm. and at the fifth pair of thecae 1-25 mm. The thecae are spaced at the rate of eleven thecae per centi- metre decreasing distally to nine per centimetre. The excavations are deep and occupy slightly more than half of the width of the rhabdosome and about half the margin of the rhabdosome. The geniculum is rounded and the supragenicular wall is inclined to the rhabdosome length. The apertures appear to be approximately horizontal. The overlap is apparently very small. Some trace of the septum can be seen although the view pre- served is the reverse; this is apparently the result of intense flattening. The proximal end is damaged, so that the lengths of the first thecae cannot be determined with any ac- curacy, but the aperture of thl 1 is at least 1 mm. above the proximal end of the rhabdo- some. Dimensions (in millimetres) Specimen Number Flat or relief Length of rhabdosome Width Length Sic- ula thS1 to thl 1 Tlijcm. thl th5 maxi- mum thl1 thl 2 thl -2 th4-5 B.U. 1272 F 34-5 07 1-5 1-5 10+ 1-4+ 3-8 11 c.9 Remarks. This is the largest form of G. tamariscus in this collection. It differs from the other forms in the distinct inclination of the thecae, in which respect it resembles G. serratus, but G. serratus is a much larger and coarser species. The specimen of G. tamariscus linearis described here is from a horizon considerably lower than the one at which the form occurs in Bohemia, the zone of Demirastrites convolutus (Pribyl 1948). Other distinguishing features have been mentioned above (see G. tamariscus tamariscus). Glyptograptus tamariscus distans subsp. nov. Plate 71, figs. 9-10; text-figs. 1 k-l Holotype. The specimen figured as text-fig. 1/ and Plate 71 fig. 9, from F horizon (Sudbury 1958) of the Monograptus gregarius zone, Rheidol Gorge, near Aberystwyth, SM. A24942. Number of specimens. Two. Horizons and localities. Approximately the base of the zone of Monograptus cyphus at Dobb’s Linn (SM. A51428) and the Monograptus gregarius Zone (F horizon) at Rheidol Gorge. Diagnosis. Narrow form of G. tamariscus (0-8 mm. flattened), parallel-sided, inter- apertural distance a little over a millimetre, thecal excavations narrow, supragenicular wall long and perpendicular. Description. Both specimens have a preserved length of approximately 10 mm. (the holotype is preserved partly as a cast). The width at thl1 is 0-5 mm. in the flattened specimen and 0-4 mm. in the specimen in relief. Both specimens are almost parallel- sided distally to the first pair of apertures and tapered proximally to them. The base 508 PALAEONTOLOGY, VOLUME 5 of th 1 1 extends about 0-1 mm. below the aperture of the sicula and proximal to it is a stout virgella. The flattened specimen from Dobb’s Linn shows the reverse view so that the length of the sicula cannot be determined, but it is visible for 045 mm. before being obscured by thl2. In the Rheidol Gorge specimen the sicula is apparently exposed for its entire length (1 4 mm.) extending upwards to a little above the aperture of thl2. There are eight or nine thecae per centimetre at the proximal end, decreasing to about seven per centimetre by the fifth pair of thecae. The supragenicular walls are straight and parallel to the sides of the rhabdosome, averaging 0-8 mm. long. The excavations are shallow, occupying less than half of the width of the stipe even in the flattened specimen. The excavation has an average length of 0-3 mm. being somewhat less for the first couple of thecae. The sigmoidal curvature of the thecae is gentle and the thecal overlap is of the order of a quarter of the thecal length. The apertures are everted. The septum is developed only on the obverse side. Dimensions (in millimetres) Flat Width Length thS1 to thl 1 Th\cm. Specimen Number or relief Length of rhabdosome th\ th5 maxi- mum thl 1 thl2 Sic- ula thl-2 thA- 5 SM. A51428 F 1 1 0-5 0-65 0-8 10 1-4 4-9 8 7 SM. A24942 R 10 0-4 0-5 0-5 105 1-5 1-4 4-9 9 1\ EXPLANATION OF PLATE 71 All figures except fig. 13, x7-5. Horizons and localities given in text. Fig. 1. Glyptograptus tamariscus tamariscus (Nicholson), form B; SM. A20383, reverse of specimen in half relief. Figs. 2-3. Glyptograptus tamariscus tamariscus (Nicholson) form A. 2, SM. A24934, reverse of specimen in relief. 3, obverse of same specimen. Fig. 4. Glyptograptus tamariscus tamariscus (Nicholson), form B; SM. A51421, reverse of specimen in half relief. Fig. 5. Glyptograptus sp. cf. G. tamariscus fastigans (Haberfelner); SM. A51443, impression of reverse of flattened specimen. Fig. 6. Climacograptus tamariscoides sp. nov. SM. A24924, obverse of specimen in relief. Figs. 7-8. Glyptograptus tamariscus angulatus subsp. nov. 7, SM. A51440, obverse of specimen in re- lief. 8, SM. A24926, holotype, reverse of specimen in relief. Figs. 9-10. Glyptograptus tamariscus distans subsp. nov. 9, SM. A24924, holotype, obverse of specimen in relief. 10, SM. A5I428, reverse of flattened specimen. Fig. 11. Glyptograptus tamariscus (Nicholson), form C. SM. A51003, proximal part of long flattened specimen. Fig. 12. Glyptograptus tamariscus acutus; SM. A24952, reverse of specimen in relief. Fig. 13. Glyptograptus tamariscus tamariscus (Nicholson), form C. BM (NH) 24953, possible holotype, obverse of flattened specimen, X8-75. Figs. 14-17. Glyptograptus tamariscus various subsp. nov. 14, SM. A51435, reverse of flattened speci- men. 15, SM. A51439, holotype reverse of specimen in relief. 16, SM. A24925, obverse of specimen in relief. 17, reverse of same specimen. Figs. 18-19. Glyptograptus enodis enodis subsp. nov. 18, SM. A24973, holotype, obverse in relief. 19, SM. A51450, obverse in relief. Fig. 20. Glyptograptus enodis lotus subsp. nov. SM. A24967, holotype, reverse in relief. Fig. 21. Glyptograptus enodis enodis subsp. nov. SM. A51453, reverse of specimen in relief. Palaeontology, Vol. 5 PLATE 71 12 13 14 15 16 17 20 21 PACKHAM, Lower Silurian diplograptids G. H. PACKHAM: BRITISH SILURIAN DI PLOG R APTI DS 509 Remarks. In size and general form G. tamariscus distans is closest to G. tamariscus angu- latus, but differs from it in having a much shallower and shorter excavation. G. tama- riscus angulatus also has a more abrupt geniculation. Glyptograptus tamariscus various subsp. nov. Plate 71, figs. 14-17; text-figs. 1 a-f Holotype. The specimen figured as text-fig. Id and Plate 71, fig. 5, from C horizon (Sudbury 1958) of the Monograptus gregarius Zone, Rheidol Gorge, near Aberystwyth, SM. A51439. Number of specimens. Twelve. Horizons and localities. Dobb’s Linn; low in the zone of M. cyphus (SM. A51429, SM. A51430), middle of the same Zone (SM. A51431, SM. A51432), top of the zone (SM. A51434, SM. A51435), lower part of the M. gregarius zone (SM. A5 1436, SM. A51437). Rheidol Gorge: zone of M. gregarius, horizon D (SM. A51738), horizon C (SM. A24925, SM. A24927, SM. A51439). Diagnosis. Short narrow form of Glyptograptus tamariscus reaching maximum width by at least the third pair of thecae and thereafter parallel-sided or decreasing in width, geniculum becoming more gentle distally. Description. The longest specimen is 8 mm. in length. The width of the rhabdosome is approximately uniform throughout the length or narrows distally. The widest specimen reaches a maximum width of IT mm. Accompanying the tendency for the rhabdosome to narrow distally there is a change in the thecal shape; distally the geniculum is rounder and the excavation a little deeper, giving the thecae a more gentle sigmoidal curvature. The proximal end of the rhabdosome is robust and th 1 1 varies in length between 0-75 and 1T5 mm. The sicula has between 1-0 and 1-4 mm. of its length visible on the ob- verse side, this could be as high as T6 mm. in one specimen. Thecae are at the rate of eleven to fourteen per centimetre at first, decreasing somewhat in most specimens towards the distal end. Dimensions {in millimetres ) Specimen Number Flat or relief Length of rhabdosome Width Length Sic- ula thS1 to th l1 Th/ cm. thl th5 maxi- mum thl1 th\ 2 thl-2 //i4-5 SM. A51430 F 4 0-65 0.7 0-7 0-95 1-2 3-6 12J 103 SM. A51429 F 6-5 0-65 c.1-0 10* 0-90 115 30 14 101 SM. A51431 F 8 10 0-95 11 11 1-6 ?1 -6 30 13 12 (th2) SM. A51432 F 7 0-7 0-75 0-8 115 1-5 1-4 3-2 13 1 1 SM. A51434 F 5 0-65 0-8 0-8 0-95 115 30 13 13 SM. A51435 F 7 0-7 0-75 0-8 0-95 1-5 3-3 12 lOi (th3) SM. A51436 F 6 0-7 0-75 0-9 M 1-6 ?1 -0 3-3 14 11 SM. A51437 F 6-5 0-7 0-85 0-85 0-75 1 35 3-5 HI 10| SM. A51438 R 4-3 0-6 0-6f 0-7 ?0-9 1-2 3-4f 12 1 If SM. A51439 R 4-5 0-55 0-6 0*65 0-9 1-2 3-5 12| 11J SM. A24925 R 4-1 0-55 0-8 0-80 0-85 1-25 10 3-2f 12| c. 10 SM. A24927 R 2-5 0-45 0-55 ?10 1-4 ?1 -4 12 * Specimen preserved in twisted position. f Extrapolated. 510 PALAEONTOLOGY, VOLUME 5 Remarks. The parallel-sided nature of the rhabdosome with its relatively robust proximal end distinguishes this form from all others. It is shorter and more robust than Glypto- graptus tamariscus tamariscus, its thecae are more closely spaced than G. tamariscus distans and it is a broader form than G. tamariscus angulatus. Glyptograptus tamariscus angulatus subsp. nov. Plate 71, figs. 7-8; text-figs. 3 a-c Holotype. The specimen figured as text-fig. 3 b and Plate 71, fig. 8, from horizon C (Sudbury 1958) of the zone of Monograptus gregarius from Rheidol Gorge near Aberystwyth, SM. A24926. text-fig. 3. a-c. Glyptograptus tamariscus angulatus subsp. nov. a. Reverse of specimen in relief, SM. A24976. b, Holotype, reverse of specimen in relief, SM. A24926. c, Obverse of specimen in relief, SM. A51440. d, G. tamariscus acutus. Reverse of specimen in relief, SM. A24952. e, Climacograptus tamariscoides sp. nov. Holotype, obverse of specimen in relief. SM. A24924. /, Glyptograptus sp. cf. G. tamariscus fastigans Haberfelner. Impression of reverse of flattened specimen, SM. A51443. g-k. Climacograptus tangshanensis linearis subsp. nov. g, Holotype, obverse of flattened specimen, SM. A51448. h, Obverse of flattened specimen, SM. A51446. Impression of reverse of flattened specimen, SM. A51444. j, Obverse of flattened specimen, SM. A51449. k, Reverse of flattened specimen, SM. A51447. All figures x 7-5. Horizons and localities given in text. Number of specimens. Five. Horizons and localities. Dobb’s Linn; near the top of the zone of M. cyphus (SM. A51441). Rheidol Gorge; at the top of the M. cyphus Zone (SM. A24976) from horizon T, and the M. gregarius Zone, horizon G (SM. A51441) and horizon C (SM. A24926, SM. A51442). Diagnosis. Narrow, short form, parallel-sided, geniculum relatively abrupt, supra- genicular wall long and perpendicular, thecal excavation deep. Description. The length of the longest specimen of this form is 7 mm. and the width of specimens preserved in relief at the first pair of thecae is 0-4 mm. and 0-5 mm. in the G. H. PACKHAM: BRITISH SILURIAN DIPLOGRAPTIDS 511 flattened specimen (Dobb’s Linn), distally the form widens slightly, but proximally it tapers evenly to a pointed proximal extremity. The base of thl 1 extends slightly below the aperture of the sicula and there is a short virgella. The supragenicular walls are straight and parallel to the sides of the rhabdosome averaging 0-7 mm. in length. The geniculum is abrupt rather than flowing, but not angular. The infragenicular wall is moderately to slightly concave longitudinally and planar transversely. The excavations occupy approximately half the width of the rhabdosome in specimens preserved in relief. The apertures are everted, the overlap of the thecae is less than a third. There are between 9 and 1 17 thecae per centimetre initially, decreasing distally. Dimensions (in millimetres) Specimen Number Fiat or relief Length of rhabdosome Width Length Sic- ula th5l to thl 1 Thl cm. thl th5 maxi- mum thl 1 thl- thl -2 tlA- 5 SM. A24976 R 5-5 0-4 0-5 0-5 095 1-4 3-9 11* 104 SM. A24926 R 5-6 0-45 0-5 0-5 11 1-5 4-3 10 8* SM. A51440 R 40 04 0-55 1-35 ?1 -7 1-45 9* SM. A51441 F 3-7 0-5 0-65 10 1-6 c.1-5 9 SM. A51442 R 3-3 0-4 0-5 10 c.1-35 1-5 9 Remarks. The geniculum of this subspecies is the most angular of any of the subspecies of G. tamariscus and hence comes closest to Climacograptus, but there is still some round- ing of the geniculum. Glyptograptus tamariscus angulatus is close to G. tamariscus distans, but differs from it in two respects, the sharper geniculation, and the deeper and longer excavation. Glyptograptus tamariscus acutus subsp. nov. Plate 71, fig. 12; text-fig. 3d Number of specimens. One. Locality and horizon. Rheidol Gorge; Monograptus gregarius Zone, horizon H of Sudbury (1958), SM. A24952. Diagnosis. Narrow (0-5 mm.), parallel-sided, interapertural distance averages 0-9 mm. for the first five thecae. Thecal overlap small, geniculation abrupt proximally becoming gentle distally. Supragenicular wall parallel to sides of rhabdosome. Theca l1 has its aperture 0-8 mm. from proximal end of rhabdosome. Description. The specimen is 6 mm. long and has a uniform width of 0-5 mm. but it is distorted in the region of thl2. Below the first pair of thecae the form tapers sharply. The base of theca l1 is level with the aperture of the sicula. The length of the sicula is not known since only the reverse side is visible, but here it is exposed for 0-2 mm. before being obscured by thl2. The thecae are closely spaced at first (fifteen per centi- metre) decreasing to ten per centimetre by the fifth pair of thecae. The supragenicular walls are straight and parallel to the side of the rhabdosome averaging 0-65 mm. long. The geniculation is abrupt at first, but appears to become slightly more flowing distally. 512 PALAEONTOLOGY, VOLUME 5 The infragenicular wall is approximately planar. The excavations are moderately deep, occupying half of the width of the rhabdosome, and the apertures are strongly everted. Dimensions (in millimetres) Specimen Number Flat or relief Length of rhabdosome Width Length Sic- ula thS1 to thl1 Th\cm. thl th5 maxi- mum thl1 thl2 thl -2 thA-5 SM. A24952 R 6 ? 0-5 0-5 0-8 11 3-5 15 10 Remarks. This form is clearly closely related to G. tamariscus angulatus and G. tama- riscus various. The geniculum is more angular than G. tamariscus angulatus proximally, and the thecae are more closely spaced. Like G. tamariscus various the thecae change in shape distally becoming more gently curved, but G. tamariscus various is a much more robust form. Glyptograptus sp. cf. G. tamariscus fastigans Haberfelner Plate 71, fig. 5; text-fig. 3/ 1931a Glyptograptus tamariscus mut fastigans Haberfelner, p. 105, pi. 3, figs, \la-e. Number of specimens. One. Locality and horizon. Knock, Swindale Beck, immediately downstream from the smash belt between Ashgill shales and Browgill Beds, stratigraphically below locality c of Shotton (1935), zone of Mono- graptus turriculatus, SM. A51443. Description. The rhabdosome is wedge-shaped, 5-6 mm. long, tapering evenly throughout and reaching a width of a fraction over 1 mm. at the distal end. The periderm is robust, preserved as a thick, shiny, carbonaceous film. The specimen is partly an obverse view and partly a reverse view. It appears that no septum is present. The proximal end of the rhabdosome is finely pointed leaving the sicula prominent. The sicula is visible in the reverse view for 0-7 mm. before being obscured by thl2. The aperture of th 1 1 is 1-0 mm. from the proximal end of the rhabdosome and that of thl2 is 1-2 mm. from the proximal end. The thecae are narrow in the apertural region, with everted apertures. The ex- cavations are long and shallow, of approximately the same depth throughout the rhabdosome (0T5 mm.), thus occupying a much smaller proportion of the width of the rhabdosome distally than proximally. The length of the thecae is difficult to determine; the overlap appears to be at least a third and could be well over a half. The interthecal distance is 0-9 mm. (eleven thecae per centimetre) for thl to th2 increasing to IT mm. (nine thecae per centimetre) distally. Dimensions (in millimetres ) Specimen Number Flat or relief Length of rhabdosome Width Length Sic- ula th5l to thl1 Th/ cm. thl th5 maxi- mum thl 1 thl2 thl-2 th4 5 SM. A51443 F 5-6 0-5 105 M0 10 L25 41 11 101- G. H. PACKHAM: BRITISH SILURIAN DIPLOGR APTIDS 513 Remarks. This specimen is very similar to G. tamariscus fastigans, but differs from it in having its apertures everted rather than introverted, and the thecal overlap in this present specimen could be larger. The horizon of the specimen from Knock is the same as Haberfelner’s specimens from the Carnic Alps. The narrowness of the apertural region of this form and the consequent shallowness of the excavations, makes it doubtful whether it should be referred to G. tamariscus at all. It has much in common with G. elegans especially in the way that the axial part of the rhabdosome increases distally. The apertures are more restricted than those of G. elegans. Genus climacograptus Hall 1865 Climacograptus tamariscoides sp. nov. Plate 71, fig. 6; text-fig. 3e Holotype. The specimen figured as text-fig. 3. 1952 Leiotriletes subintortus (Waltz) Ishchenko var. rotundatus Waltz; Ishchenko, p. 11; pi. 1, fig. 7. Description of specimens. Spores radial, trilete ; amb subtriangular with rounded apices EXPLANATION OF PLATE 78 All figures X 500, and from unretouched negatives. Figs. 1, 2. Chaetosphaerites pollenisimilis (Horst) Butterworth and Williams 1958. 1, Preparation P145C/2, 27-8 97-8 (L.939). 2, Preparation P145B/22, 36-1 103-2 (L.940). Figs. 3, 4. Leiotriletes inermis (Waltz) Ishchenko 1952. 3, Proximal surface; preparation M811/5, 38-3 100-9 (L.941). 4, Proximal surface; preparation P034/1, 35-8 103-8 (L.942). Figs. 5, 6. L. subintortus (Waltz) Ishchenko 1952 var. rotundatus Waltz 1941. 5, Proximal surface; pre- paration P163/6, 18-2 99-2 (L.943). 6, Proximal surface; preparation P163/7, 36-0 94-8 (L.944). Figs. 7, 8. L. ornatus Ishchenko 1956. 7, Proximal surface; preparation P163/5, 29-3 106-2 (L.946). 8, Proximal surface; preparation P163/6, 39-0 95-9 (L.945). Fig. 9. L. curiosus sp. nov. Holotype; proximal surface. Figs. 10, 11. L. microgranulatus sp. nov. 10, Proximal surface; preparation P181/4, 52-3 112-4 (L.948). 1 1 , Holotype ; distal surface. Figs. 12, 13. Punctatisporites labiatus sp. nov. 12, Holotype; proximal surface. 13, Proximal surface; preparation P163/5, 22-0 92-4 (L.957). Fig. 14. P. parvivermiculatus sp. nov. Holotype; distal surface. Figs. 15, 16. P. glaber (Naumova) comb. nov. 15, Proximal surface; preparation P148/1, 35-6 109-7 (L.952). 16, Proximal surface; preparation P163/5, 46-0 107-2 (L.953). Figs. 17, 18. P. pseudobesus sp. nov. 17, Proximal surface; preparation P149A/31, 36-3 105-0 (L.960). 18, Holotype; proximal surface. Palaeontology, Vol. 5 PLATE 78 PLAYFORD, Lower Carboniferous microspores G. PLAYFORD: LOWER CARBONIFEROUS MICROSPORES 575 and concave sides. Laesurae distinct, straight, simple, extending almost to smooth equatorial margin. Exine 1-2 p thick, laevigate. Dimensions (45 specimens). Equatorial diameter 26-50 p (mean 38 p). Comparison. Gramdatisporites adnatus Kosanke 1950 has a definite contact area, but G. adnatus ? in Wilson and Hoffmeister (1956, p. 16; pi. 2, fig. 9) lacks this feature and is probably conformable with L. subintortus var. rotundatus. Previous records. Apparently widespread in the Russian Lower Carboniferous, with previous records from Luber and Waltz (1941) and Ishchenko (1952, 1956, 1958), whose work indicates a range from Tournaisian to Bashkirian for this variety. Leiotriletes ornatus Ishchenko 1956 Plate 78, figs. 7, 8 1956 Leiotriletes ornatus Ishchenko, p. 22; pi. 2, figs. 18-21. 1960 Spore type 1 of Love, p. 122; pi. 2, fig. 9 and text-fig. 12. Description of specimens. Spores radial, trilete ; amb subtriangular with convex to almost straight sides. Laesurae distinct, straight, length approximately equal to spore radius; with prominent, dark, raised lips individually 2-5-4-5/x wide. Exine 2-3-5 p thick, laevigate or occasionally sparsely infrapunctate (oil immersion). Dimensions (55 specimens). Equatorial diameter 32-63 p (mean 46 p). Comparison. The two specimens described by Love (1960, p. 122) are undoubtedly representative of this species; the apparent ‘equatorial thickening’ has been observed in a number of the Spitsbergen specimens, and, as suggested by Love, is the result of exinal folding due to compression. Spore type C of Neves (1958, p. 12; pi. 2, fig. 6) has an ‘equatorial flange’ according to the description, and the lips have considerably greater development than those of L. ornatus. Filicitriletes pyramidalis (Luber in Luber and Waltz 1941, p. 54; pi. 12, fig. 182) Luber 1955 (p. 60; pi. 3, fig. 20) is larger than L. ornatus and appears to have only minor lip development. Previous records. Ishchenko (1956) found this species to be restricted to Middle Visean-Lower Nam- urian strata of the Western Donetz Basin. An interesting recent record is from the Pumpherston Shell Bed (Visean) of Scotland (Love 1960). Leiotriletes microgranulatus sp. nov. Plate 78, figs. 10, 11 Diagnosis. Spores radial, trilete; amb broadly roundly subtriangular. Simple, straight, distinct laesurae equal half to three-fifths of spore radius. Equatorial margin smooth. Exine 3-4-5 p thick, finely and densely granulate (‘peppery’ appearance under oil immersion). Dimensions (25 specimens). Equatorial diameter 58-86 p (mean 70 p). Holotype. Preparation P176A/2, 23-5 95-2. L.947. Locus typicus. Citadellet (sample G1451), Spitsbergen; Lower Carboniferous. 576 PALAEONTOLOGY, VOLUME 5 Description. Holotype subtriangular with slightly convex sides and broadly rounded apices, diameter 73^; laesurae one-half spore radius; minutely granulate exine, 4p in thickness. Comparison. Leiotriletes convexus (Kosanke 1950, pp. 20-21; pi. 3, fig. 6) Potonie and Kremp 1955 has similar sculpture but a thinner exine and longer laesurae. Leiotriletes curiosus sp. nov. Plate 78, fig. 9; text-fig. 5b Diagnosis. Spores radial, trilete; amb subtriangular with straight to slightly concave sides and broad, bluntly rounded apices. Laesurae distinct, simple, straight or slightly undulating, length approximately four-fifths spore radius. Exine thin (less than 1 p), laevigate or faintly roughened (oil immersion). The (six) equatorial junctions between apical shoulders and interradial sides are each marked by a small, rounded, relatively broad-based granule. Dimensions (25 specimens). Equatorial diameter, 28^40 /x (mean 35 p). Holotype. Preparation P149B/1, 38-8 97-6. L.950. Locus typicus. Triungen (sample G1470), Spitsbergen; Lower Carboniferous. Description. Elolotype 38 p; one laesura bordered by narrow folds simulating lips. Remarks. On the basis of subtriangular shape and mainly smooth surface, this species is included within Leiotriletes, rather than in Granulatisporites which incorporates similarly shaped, but densely granulate spores. Genus punctatisporites (Ibrahim) Potonie and Kremp 1954 Type species. P. punctatus Ibrahim 1933. Affinity. Psilopsida, Filicineae, Cycadofilicineae? (after Potonie and Kremp 1955, p. 42; 19566, p. 81). Punctatisporites glaber (Naumova) comb. nov. Plate 78, figs. 15, 16 1938 Azonotriletes glaber (Naumova) Waltz in Luber and Waltz, p. 8; pi. 1, fig. 2 and pi. A, fig. 3. 1952 Leiotriletes glaber (Waltz) Ishchenko, pp. 13-14; pi. 2, figs. 15, 16. 1955 Calamospora glabra (Naumova) Potonie and Kremp, p. 47. 1955 Punctatisporites nitidus Hoffimeister, Staplin, and Malloy, pp. 393-4; pi. 36, fig. 4. 1955 Punctatisporites! callosus Hoffmeister, Staplin, and Malloy, p. 392; pi. 39, fig. 7. 1956 Leiotriletes glaber Naumova; Ishchenko, pp. 18-19; pi. 1, figs. 7, 8. 1958 Punctatisporites cf. nitidus Hoffmeister, Staplin, and Malloy; Butterworth and Williams, p. 361 ; pi. 1, figs. 7, 8. 1960 Punctatisporites curviradiatus Staplin, p. 7; pi. 1, figs. 17, 20. Description of specimens. Spores radial, trilete; equatorial outline circular. Laesurae distinct, simple, straight, length one-third to two-thirds spore radius. Exine 1-5-2 p thick, laevigate (corroded specimens finely punctate); rarely folded. Dimensions (38 specimens). Equatorial diameter 32-70 p (mean 52 p). G. PLAYFORD: LOWER CARBONIFEROUS MICROSPORES 577 Remarks. The above synonymy does not attempt to be exhaustive. Several other species, for example Punctatisporites planus Hacquebard 1957 (p. 308; pi. 1, fig. 12), may well prove to be conspecific with P. glaber. The intention, however, is to emphasize the mul- titudinous nomenclature prevailing among such simple, circular, laevigate spores, and particularly those occurring in the Carboniferous System. As these forms are apparently of limited stratigraphical value there seems little point in attempting a rigorous sub- division (particularly on the basis of minute variations in such few and simple morpho- graphical characters), and certainly the validity of naming a spore according to its stratigraphical horizon is extremely doubtful. It is, of course, recognized that the dis- persed spores included within P. glaber are probably representative of several different plants. Staplin (1960, p. 7) in discussing his new species Punctatisporites curviradiatus states that ‘off-polar compression and resultant apparent curvature of two sutures distinguish this species from P. nitidus Hoffmeister, Staplin and Malloy’. This appears rather a questionable basis for specific distinction. The illustrations given by Waltz (in Luber and Waltz 1938 and 1941) of P. glaber include identical spores showing this same feature. Comparison with Staplin’s ( 1960) species is often difficult owing to the fact that relative terms only are used in stating the thickness of the spore wall (e.g. ‘moderate’). Punctatisporites glaber (Naumova) comb. nov. was assigned to the genus Calaniospora by Potonie and Kremp (1955, p. 47); however, its relatively thick, rarely folded exine, together with fairly extensive laesurae, indicate more appropriate inclusion within Punctatisporites. Previous records. Numerous previous records from the Carboniferous (see synonymy above). Accord- ing to Ishchenko (1958) this species ranges from Devonian to Bashkirian. Punctatisporites parvivermiculatus sp. nov. Plate 78, fig. 14; text-fig. 5k Diagnosis. Spores radial, trilete; amb circular to subcircular. Laesurae distinct, more or less straight, equal three-quarters or more of spore radius, sometimes with incipient lips. Exine 2-3^ thick; sculpture infravermiculate with very fine, shallow, short, anastomosing grooves indenting the otherwise laevigate spore wall, constituting a highly imperfect negative microreticulum. Dimensions (30 specimens). Equatorial diameter 58-88 /x (mean 74 p). Holotype. Preparation P169/1, 31-3 98-1. L.954. Locus typicus. Birger Johnsonfjellet (sample G1086), Spitsbergen; Lower Carboniferous. Description. Holotype subcircular, equatorial margin undulating due to folding, diameter 68 p; laesurae slightly curved due to compression, length approximately three-quarters spore radius; exine 3p in thickness, with peripheral arcuate folds. In many specimens the nature of the exinal sculpture is evident only under oil immersion. The grooves never attain the dimensions necessary to delimit definite positive processes, such as verrucae or grana. Comparison. Punctatisporites vermiculatus Kosanke 1950 (p. 19; pi. 2, fig. 4) is similar. 578 PALAEONTOLOGY, VOLUME 5 but has a thicker exine deeply incised by a more extensively developed vermiculate sculpture. Potonie and Kremp (1955, p. 104) considered that P. vermiculatus may per- haps be referable to Ccmiptotriletes. However, P. parvivermiculatus sp. nov. with its relatively minor sculpture is more appropriately included within Punctatisporites. Pwietatisporites labiatus sp. nov. Plate 78, figs. 12, 13 Diagnosis. Spores radial, trilete; amb circular. Laesurae straight, length two-thirds to three-quarters spore radius; emphasized by prominent, smooth, slightly raised lips, individually 3^1 p wide. Exine 3-4-5 p thick; laevigate to indistinctly infragranulate. Dimensions (20 specimens). Equatorial diameter 69-113 p (mean 88 ft). Holotype. Preparation P163/1, 30 0 97-3. L.956. Locus typicus. Birger Johnsonfjellet (sample G1089), Spitsbergen; Lower Carboniferous. Description. Holotype circular, diameter 94 /x ; laesurae equal three-quarters spore radius, rimmed by pronounced, dark lips 4 p wide; exine 3 p thick, laevigate, not folded. Other specimens occasionally show minor peripheral folding. Comparison. This species resembles Punctatisporites flavus (Kosanke 1950, p. 41 ; pi. 9, fig. 2) Potonie and Kremp 1955, but differs in having longer laesurae, with more pro- nounced and regular lip development. Azonotriletes microrugosus (Ibrahim) forma karagandensis Luber (in Luber and Waltz 1938, p. 22; pi. 5, fig. 56) is smaller with incipient lips and thinner, folded exine. Punctatisporites pseudobesus sp. nov. Plate 78, figs. 17, 18 Diagnosis. Spores radial, trilete; amb circular, oval or broadly roundly subtriangular. Laesurae distinct, straight, length one-half to two-thirds spore radius. Exine perceptibly infragranulate (oil immersion), thickness 5-5-8 p (average Ip ); folding infrequent. Dimensions (35 specimens). Equatorial diameter 97-157 p (mean 125 ft). Holotype. Preparation P149A/22, 31-8 101-3. L.959. Locus typicus. Triungen (sample G1470), Spitsbergen; Lower Carboniferous. Description. Holotype circular, 121 p in diameter, laesurae about three-fifths spore radius, exine 7 p thick. Comparison. The closely allied species, Punctatisporites obesus (Loose) Potonie and Kremp (1955, p. 43; pi. 11, fig. 124), has a thinner spore wall (up to 5 p), somewhat shorter laesurae, and a different size range. Punctatisporites stabilis sp. nov. Plate 79, figs. 1, 2 Diagnosis. Spores radial, trilete, originally spherical; amb circular, practically smooth. G. PLAYFORD: LOWER CARBONIFEROUS MICROSPORES 579 Laesurae distinct, simple, straight or slightly curved, length approximately three- quarters spore radius. Exine 1 -5-2-5 p thick; with distinct, minute (less than 1 p across), shallow punctations scattered on both proximal and distal hemispheres. Exinal folding rare. Dimensions (45 specimens). Equatorial diameter 63-94 p, (mean 76 ^). Holotype. Preparation P158/7, 31-5 114-5. L.962. Locus typicus. Birger Johnsonfjellet (sample G1092), Spitsbergen; Lower Carboniferous. Description. Holotype 90 p; exine 2-5 /x in thickness; punctae fairly uniformly dis- tributed, c. 4 /x apart, occasionally slightly elongate forming short grooves up to 2 /x long. Comparison. Azonotriletes punctulatus Waltz var. gigantens Waltz (in Luber and Waltz 1941, p. 14; pi. 2, fig. \6a) appears similar to Punctatisporites stabilis sp. nov., but differs in having an oval outline, shorter laesurae and generally larger size (90—1 1 5 p); closer comparison is difficult owing to the brevity of Waltz’s description. Another rather similar species, Punctatisporites punctatus Ibrahim 1933 (Potonie and Kremp 1955, p. 45; pi. 11, figs. 122, 123), is distinguishable from P. stabilis on the basis of its longer laesurae, broadly roundly triangular amb, and infrapunctate sculpture. Genus calamospora Schopf, Wilson, and Bentall 1944 Type species. C. hartungiana Schopf in Schopf, Wilson, and Bentall 1944. Affinity. Sphenophyllaceae?, Calamariaceae, Noeggerathiales (after Potonie and Kremp 1954, p. 123). Spores conformable with Calamospora have been reported by Kosanke (1955) from his homosporous Calamarian species Mazostachys pendulata; and by W. and R. Remy (1957) from Noeggerathiostrobus vicinalis E. Weiss, Discinites sp. cf. bohemicus K. Feistmantel, and Discinites sp. Spores which appear to closely resemble Calamospora were recovered by Walton (1957) from his new species Protopity s scotica, a fertile shoot from the Calciferous Sandstone Series (Lower Carboniferous) of Dunbarton- shire, Scotland. On the evidence of P. scotica , Walton considered that Protopitys had pteridophytic reproduction and proposed a new group, the Protopityales, to include the genus. Calamospora microrugosa (Ibrahim) Schopf, Wilson, and Bentall 1944 Plate 79, figs. 3, 4 1932 Sporonites microrugosus Ibrahim in Potonie, Ibrahim, and Loose, p. 447; pi. 14, fig. 9. 1933 Laevigati-sporites microrugosus (Ibrahim) Ibrahim, p. 18; pi. 1, fig. 9. 1938 Azonotriletes microrugosus (Ibrahim) Waltz in Luber and Waltz, p. 10; pi. 1, fig. 1 and pi. A, fig. 1. 1944 Calamospora microrugosa (Ibrahim) Schopf, Wilson, and Bentall, p. 52. 1952 Leiotriletes microrugosus (Ibrahim) Ishchenko, p. 15; pi. 2, fig. 19. 1955 Calamotriletes microrugosus (Waltz) Luber, p. 36; pi. 1, figs. 1-3. Description of specimens. Spores radial, trilete, originally spherical; amb circular to subcircular (modified by folding). Laesurae distinct, straight, length one-half to two- thirds spore radius, sometimes with faint, narrow, lip development. Equatorial margin smooth. Exine very thin (usually less than Ip); laevigate or very minutely granulate (oil immersion), characteristically strongly plicated with folds of both major and minor proportions. C 674 PP 580 PALAEONTOLOGY, VOLUME 5 Dimensions (40 specimens). Equatorial diameter 62-104 p, (mean 82 p ). Remarks. Spores similar to Calamospora microrugosa have been designated by a variety of specific names, many clearly synonymous, but until a direct comparison of the types is possible more precise assignment of the above specimens is precluded. As noted by Potonie and Kremp (1955, p. 49), Calamospora liquida Kosanke 1950 is undoubtedly very close to C. microrugosa. This is also the case with various spores described and illustrated by Ishchenko (1952, 1956, 1958) as Leiotriletes platirugosus (Waltz 1941) with three varieties, L. vetustus Ishchenko 1952, L. mitus Ishchenko 1952, and L. immanis Ishchenko 1952. The latter two species were considered synonymous with C. liquida Kosanke by Dybova and Jachowicz (1957, p. 63). Potonie and Kremp (1955), Luber and Waltz (1938, 1941), Naumova (1953), Ishchenko (1952, &c.), Luber (1955), Bolkhovitina (1956, 1959), Chibrikova (1959), and Imgrund (1960) have all recorded C. microrugosa as such. Naumova (1953) notes the vertical range as Cambrian to Cretaceous. Previous records. C. microrugosa has been recorded by numerous authors from the Carboniferous (see above). Genus phyllothecotriletes Luber 1955 Type species. P. nigritellus (Luber) Luber 1955. Affinity. Unknown. Phyllothecotriletes rigidus sp. nov. Plate 79, figs. 5, 6 Diagnosis. Spores radial, trilete ; amb circular to subcircular. Laesurae distinct, typically EXPLANATION OF PLATE 79 All figures x 500, and from unretouched negatives. Figs. 1,2. Punctatisporites stabilis sp. nov. 1, Holotype; proximal surface. 2, Proximal surface; prepara- tion PI 58/7, 24-6 96-8 (L.963). Figs. 3, 4. Calamospora microrugosa (Ibrahim) Schopf, Wilson and Bentall 1944. 3, Proximal surface; preparation P181/4, 40-4 112-6 (L.965). 4, Proximal surface; preparation P148/18, 44-8 111-8 (L.966). Figs. 5, 6. Phyllothecotriletes rigidus sp. nov. 5, Holotype; proximal surface. 6, Proximal surface; preparation P176A/3, 22-8 97-4 (L.968). Fig. 7. Waltzispora lobophora (Waltz) Staplin 1960. Distal surface; preparation P145A/1, 40-2 105-8 (L.970). Figs. 8-11. W. albertensis Staplin 1960. 8, Proximal surface; preparation P145C/2, 46-7 112-9 (L.971). 9, Distal surface; preparation P145C/1, 48-4 100-1 (L.972). 10, Proximal surface; preparation P145B/30, 38-8 101-9 (L.973). 11, Proximal surface; preparation P145C/2, 52-3 98-1 (L.974). Fig. 12. W. sagittata sp. nov. Holotype; distal surface. Figs. 13-16. Cyclogranisporites flexuosus sp. nov. 13, 14, Holotype; proximal and distal surfaces respectively. 15, Proximal surface; preparation P148/2, 45-8 94-0 (L.981). 16, Distal surface; prepara- tion P148/33, 34-7 101-7 (L.982). Fig. 17. Lophotriletes coniferus Hughes and Playford 1961. Proximal surface; preparation P175/7, 50-3 98-2 (L.993). Fig. 18. Granulatisporites planiusculus (Luber) comb. nov. Proximal surface; preparation PI 69/1, 33-9 113-5 (L.977). Figs. 19, 20. Cyclogranisporites lasius (Waltz) comb. nov. 19, Proximal surface; preparation P175/2, 19-2 97-7 (L.978). 20, Proximal surface; preparation P145A/2, 22-4 112-2 (L.979). Palaeontology , Vol. 5 PLATE 79 PLAY FORD, Lower Carboniferous microspores G. PLAYFORD: LOWER CARBONIFEROUS MICROSPORES 581 slightly sinuous; unequal in length, approximately one-third spore radius. Exine 2-4-5 n thick, very finely granulate (oil immersion), folding minor — absent. Dimensions (40 specimens). Equatorial diameter 57-77 p (mean 66 p). Holotype. Preparation PI 72/3, 45-4 93-9. L.967. Locus typicus. Citadellet (sample G1445), Spitsbergen; Lower Carboniferous. Description. Holotype circular, 62 p in diameter; exine 2-5 p thick, very minutely granulate; laesurae ± straight, approximately one-third spore radius, one slightly longer than others. Comparison. Phyllothecotriletes golatensis Staplin 1960 (p. 9; pi. 1, fig. 27) is laevigate and has shorter laesurae; P.? belloyensis Staplin 1960 (p. 9; pi. 1, fig. 23) is smaller, and has longer laesurae together with distinct contact area. Genus waltzispora Staplin 1960 Type species. W. Iobophora (Waltz) Staplin 1960. Discussion. This distinctive genus embraces relatively simple, subtriangular, trilete spores having characteristically blunted and tangentially expanded radial extremities, and sculpture which, on presently known species, ranges from granulate to laevigate. It appears to have considerable stratigraphical significance within the Lower Carboni- ferous, as evidenced herein and from observations elsewhere. Affinity. Unknown. Waltzispora Iobophora (Waltz) Staplin 1960 Plate 79, fig. 7 1884 Type 74 of Reinsch, p. 8; pi. 3, fig. 31. 1938 Azonotriletes lobophorus Waltz in Luber and Waltz, p. 12; pi. 1, fig. 5 and pi. A, fig. 8. 1941 Azonotriletes lobophorus Waltz var. simplex Waltz in Luber and Waltz, pp. 18-19; pi. 3, fig. 31. 1941 Azonotriletes lobophorus Waltz var. submarginatus Waltz in Luber and Waltz, pp. 18-19; pi. 3, fig. 32. 1956 Triquitrites lobophorus (Waltz) Potonie and Kremp, p. 87. 1960 Waltzispora Iobophora (Waltz) Staplin, p. 18. Description of specimens. Spores radial, trilete; amb subtriangular with concave to almost straight interradial margins, having conspicuous angular junctions with flatly rounded radial extremities, which thus constitute more or less prominent shoulders. Laesurae distinct, straight, length approximately four-fifths spore radius; sometimes with minor lip development in proximal polar region. Comprehensive granulate sculp- ture, particularly marked around distal pole, where grana are closely packed and com- paratively large (up to 2-5 p in basal diameter). Exine 1-5-2 p thick. Dimensions (20 specimens). Equatorial diameter 43-58 p (mean 50 p). Remarks. The not extreme morphographical variation between specimens included within this species is dearly evident from the illustrations given by Reinsch (1884) and 582 PALAEONTOLOGY, VOLUME 5 by Luber and Waltz (1938, and particularly 1941); it is confirmed by the Spitsbergen specimens recorded herein. In 1941 Waltz (in Luber and Waltz, loc. cit.) distinguished two varieties of Azonotriletes lobophorus — var. simplex (identical to pi. 1, fig. 5 in Luber and Waltz 1938) and var. submarginatus — which were not intended to be considered as discrete taxonomic units, but rather as extremes of infraspecific variation. Comparison. If the absence of granules on the proximal surface is a constant feature of Granalatisporites humerus Staplin 1960 (p. 16; pi. 3, fig. 24) it may be considered as a species distinct from W. lobophora (Waltz). In any case, the inclusion of G. humerus within Waltzispora is recommended on the basis of its close conformity to the type species in the diagnostic characters of equatorial outline and sculpture. Previous records. This species was first reported by Reinsch (1884) from Russian (? Lower) Carboni- ferous rocks, and subsequently (Luber and Waltz 1938, 1941) from the Lower Carboniferous of the Moscow Basin, and of the Selizharovo, Borovichi, and Kizel regions, U.S.S.R. Waltzispora albertensis Staplin I960 Plate 79, figs. 8-1 1 1884 Type 78 of Reinsch p. 9; pi. 22, fig. 28a. 1957 cf. Azonotriletes lobophorus Waltz; Hacquebard and Barss, pp. 44-45; pi. 6, fig. 9. 1960 Waltzispora albertensis Staplin, p. 18; pi. 4, figs. 2, 3. Description of specimens. Spores radial, trilete. Amb concavely subtriangular, with prominent, blunted, radial extremities, which are conspicuously and more or less symmetrically expanded in a tangential direction; central parts of radial extremities often embayed (towards the polar axis). Laesurae more or less straight, length three- quarters to four-fifths spore radius; occasional minor development of lips. Exine 1-5- 2 p thick; essentially laevigate but may appear slightly roughened under oil immersion. Dimensions (120 specimens). Equatorial diameter 23-37 p (mean 29 p). Note that the discrepancy between the above size range and the measurements given by Hacquebard and Barss (1957) and Staplin (1960) is only apparent. Although not specified in their texts, it is evident from the plates that they have stated the ‘angle to angle’ measurement (Harris 1955, p. 14), whilst, as mentioned previously, the present writer takes the equatorial diameter of triangular forms as the maxium median length. Remarks. The spores illustrated and described by Reinsch (1884) and Hacquebard and Barss (1957) as, respectively, type 78 and cf. Azonotriletes lobophorus Waltz 1938, are conformable in all respects with W. albertensis Staplin. Previous records. This species has been recorded previously from the Russian (? Lower) Carboniferous (Reinsch 1884), and from the Upper Mississippian of Canada (Hacquebard and Barss 1957; Staplin 1960). Waltzispora sagittata sp. nov. Plate 79, fig. 12; text-fig. 5c 1960 Leiotriletes politus ( non Hoffmeister, Staplin, and Malloy 1955, p. 389; pi. 36, fig. 13) Love, pi. 1, fig- L Diagnosis. Spores radial, trilete; amb subtriangular with concave interradial margins G. PLAYFORD: LOWER CARBONIFEROUS MICROSPORES 583 and convex, somewhat pointed, radial extremities, which also show slight, but definite, tangential expansion. Laesurae simple, straight, length at least three-quarters spore radius. Equatorial margin smooth. Exine finely granulate to almost laevigate; up to 1 p. thick. Dimensions (16 specimens). Equatorial diameter 24-35 p. (mean 29 p). Holotype. Preparation P180B/1, 54-4 105-8. L.975. Locus typicus. Birger Johnsonfjellet (sample G 1 1 02), Spitsbergen; Lower Carboniferous. Description. Holotype 27 p; proximal and distal surfaces with uniform sculpture of fairly widely spaced minute grana, which do not project at the equator; laesurae almost attain equatorial margin. Comparison. Waltzispora lobophora (Waltz) Staplin 1960 is larger, more densely gran- ulate, and the convexity of the radial extremities is less pronounced than in W. sagittata sp. nov. Zonotriletes triplex Andrejeva {in Luber and Waltz 1941, p. 18; pi. 3, fig. 33), which is almost certainly a comparatively thick-walled species of Waltzispora , is laevigate, has very deeply incised interradial margins, and ranges in size from 45 to 55 p. Remarks. The spore illustrated by Love (1960, pi. 1, fig. 1) as Leiotriletes politus (Hoff- meister, Staplin, and Malloy) appears identical to the Spitsbergen specimens described above, and seems to have little diagnostically in common with the description and illustration given by Hoffmeister, Staplin, and Malloy (1955, p. 389; pi. 36, fig. 13). Although the photograph given by Butterworth and Williams (1958, pi. 1, fig. 15) is probably of a genuine representative of Granulatisporites politus, it is possible that Waltzispora sagittata sp. nov. is present in their Scottish material, but was considered by them as a variant of G. politus. This is suggested by the statement (Butterworth and Williams, loc. cit., p. 361) regarding ‘the tendency for the rounded radial extremities to project laterally, thus giving an angular junction of radial and inter-radial areas’, an attribute which suggested to them an analogy with a ‘similar species’, Azonotriletes lobophorus Waltz (which was subsequently designated as the type species of Waltzispora). Previous records. From the Lower Oil-shale Group (Visean) of Scotland (Love 1960). Infraturma apiculati (Bennie and Kidston) R. Potonie 1956 Subinfraturma granulati Dybova and Jachowicz 1957 Genus granulatisporites (Ibrahim) Potonie and Kremp 1954 Type species. G. granulatus Ibrahim 1933. Affinity. Probably related to the Filices, and perhaps also to the Cycadofilicales (after Potonie and Kremp 1954, p. 126). Granulatisporites planiusculus (Luber) comb. nov. Plate 79, fig. 18 1955 Filicitriletes planiusculus Luber, p. 60; pi. 3, fig. 71. Description of specimens. Spores radial, trilete; amb convexly subtriangular. Laesurae distinct, straight, extending to equatorial margin; prominent, dark, elevated lips, 584 PALAEONTOLOGY, VOLUME 5 text-fig. 5. Camera-lucida drawings; all magnifications X 500 unless otherwise specified, a, Reticula- tisporites variolatiis sp. nov. ; proximal surface; preparation P166/3, 32-9 98T (L. 1 047). b, Leiotriletes curiosus sp. nov.; proximal surface; preparation P149A/1, 20-4 102-4 (L.951). c, Waltzispora sagittata sp. nov.; proximal surface; preparation P180B/2, 42-1 94-5 (L.976). d, Vermcosisporites eximius sp. nov.; proximal surface; preparation P149/A40, 35-5 109-5 (L.992). e, Stenozonotriletes perforatus sp. nov.; proximal surface; preparation P147A/1, 48-6 96-7 (L.1078). /, Anapiculatisporites serratus sp. nov. ; distal surface; preparation P149A/2, 24-3 98-9 (L. 1003). g, Vermcosisporites gobbettii sp. nov. ; proximal surface; preparation P148/2, 17-0 109-7 (L.988). h, j, Convolutispora harlandii sp. nov. ( x 250) ; distal and proximal surfaces respectively; preparation P148/12, 34-9 103-1 (L.1019). k, Punctatisporites parvivermiculatus sp. nov.; proximal surface; preparation P163/6, 36-9 105-1 (L.955). individually 2-3 ft wide. Exine 2-5-3 ft thick; distinctive, finely areolate sculpture with fairly regular, negative microreticulum encompassing fine, irregular granules. Dimensions (15 specimens). Equatorial diameter 51-71 ft (mean 60 ft). Remarks. The species is included within Granulatisporites on the basis of its subtriangular G. PLAYFORD: LOWER CARBONIFEROUS MICROSPORES 585 amb and areolate-granulate sculpture. Filicitriletes Luber 1955 lacks type-species designation and in any case embraces the categories of several well-established genera (see Potonie 1958, p. 35). Previous records. Luber (1955) recorded this species from the Lower(Cl) and Upper(C3) Carboniferous of Kazachstan. Genus cyclogranisporites Potonie and Kremp 1954 Type species. C. leopoldi (Kremp) Potonie and Kremp 1954. Affinity ■ W. and R. Remy (1957, p. 61 ; pi. 3, fig. 1 1 and pi. 4, figs. 1-3) refer to Microreticulatisporites the microspores of Noeggerathiostrobus bohemicus O. Feistmantel (Upper Westphalian B), which, however, seem more closely related to Cyclogranisporites. Potonie (1960, p. 34) has noted the re- semblance between Cyclogranisporites and the spores recovered by W. and R. Remy (1957, pi. 3, figs. 1, 2) from Acitheca ( al . Pecopteris ) longifolia Brongniart. Cyclogranisporites lasius (Waltz) comb. nov. Plate 79, figs. 19, 20 1884 Type 524 of Reinsch, p. 52; pi. 32, fig. 21 1 and pi. 42, fig. 220. 1938 Azonotriletes lasius Waltz in Luber and Waltz, p. 9; pi. 1, fig. 4 and pi. A, fig. 4. 1955 Filicitriletes lasius (Waltz) Luber, p. 55; pi. 2, fig. 50. Description of specimens. Spores radial, trilete ; amb circular. Laesurae simple, straight, length approximately two-thirds spore radius. Exine densely and finely granulate; thickness 1-3 /r. Dimensions (20 specimens). Equatorial diameter 50-88 p (mean 68 p). Remarks. Filicitriletes Luber 1955 was rejected correctly by Potonie (1958, p. 35) on the basis of its unsuitability as a generic unit, since it would embrace innumerable species already suitably placed in established genera. Potonie and Kremp (1955, p. 98) tentatively included Azonotriletes lasius Waltz within Microreticulatisporites (Knox) Potonie and Kremp. However, from the description given by Waltz (in Luber and Waltz 1938), the circular outline coupled with comprehensive granulate sculpture clearly indicates a correct assignment to Cyclogranisporites. Previous records. Luber and Waltz (1938, 1941) and Luber (1955) have reported this species from the Lower Carboniferous of European Russia and of western Kazachstan. Cyclogranisporites flexuosus sp. nov. Plate 79, figs. 13-16 Diagnosis. Spores radial, trilete; amb circular or subcircular, occasionally broadly roundly subtriangular. Laesurae approximately two-thirds to three-quarters amb radius, often totally obscured by prominent, raised, sinuous lips; overall width of lips up to 6-5 p (usually about 3 p), often varying considerably in any one specimen. Exine 3-5-5 p thick; distal hemisphere sculptured with densely distributed fine grana; proxi- mal hemisphere frequently with conspicuous laevigate-infragranulate contact faces, otherwise very finely granulate overall. 586 PALAEONTOLOGY, VOLUME 5 Dimensions (65 specimens). Equatorial diameter 44-78 p (mean 59 p). Holotype. Preparation P148/1, 40-8 94-9. L.980. Locus typicus. Triungen (sample G1472), Spitsbergen; Lower Carboniferous. Description. Holotype subcircular, diameter 62 yu. ; laesurae just perceptible, approxi- mately two-thirds spore radius, straight, with strong, dark, sinuous lips individually 3 p wide. Exine 5 p thick; apart from laevigate contact faces, exine finely but conspicu- ously granulate. Comparison. This species differs from other described representatives of Cyclograni- sporites in its distinctively lipped laesurae together with thick exine. Subinfraturma verrucati Dybova and Jachowicz 1957 Genus verrucosisporites (Ibrahim) Potonie and Kremp 1954 Type species. V. verrucosus Ibrahim 1932. Discussion. This genus and Convolutispora Hoffmeister, Staplin, and Malloy are closely related morphographically. Verrucosisporites is characterized by closely spaced verrucae whilst the sculpture of Convolutispora consists typically of crowded, anastomosing rugulae. Some difficulty is experienced in the generic assignment of species, e.g. Con- volutispora clavata (Ishchenko), which possess composite rugulate/verrucate sculpture ; in such instances the decision must rest upon an assessment of the predominating type of sculpturing elements. Affinity. W. and R. Remy (1957) have recovered spores conformable with Verrucosisporites from the Upper Carboniferous fern fructifications Corynepteris silesiaca R. and W. Remy, Zygopteris sp., and Wahienburgia corynepteroides Gothan. Verrucosisporites gobbettii sp. nov. Plate 80, figs. 1-4; text-fig. 5 g Diagnosis. Spores radial, trilete ; amb circular to subcircular. Laesurae simple, straight, length two-thirds to three-quarters spore radius. Conspicuous sculpture of numerous, somewhat irregularly distributed verrucae, both discrete and coalescent, having circular to elliptical bases and broadly rounded apices; basal diameter of verrucae 4—12 (average 8 p), height 2-3 p. Surface between verrucae laevigate or very faintly infrapunctate; thickness of exine (excluding verrucae) 2 p. Dimensions (50 specimens). Equatorial diameter 55-89 p (mean 72 p). Holotype. Preparation P148/42, 48-8 105-2. L.984. Locus typicus. Triungen (sample G1472), Spitsbergen; Lower Carboniferous. Description. Holotype circular, diameter 88 p, amb undulating due to verrucae; laesurae distinct, equal three-quarters spore radius; one minor peripheral fold. Although comprehensive, the verrucate sculpture is, in most specimens, more pronounced on the distal hemisphere. Comparison. Verrucosisporites scrobiculatus (Luber in Luber and Waltz 1938, p. 24; G. PLAYFORD: LOWER CARBONIFEROUS MICROSPORES 587 pi. 5, fig. 70) Potonie and Kremp 1955 has more closely spaced, less broadly based pro- jections, together with shorter laesurae. V. baccatus Staplin 1960 (p. 12; pi. 2, figs. 4, 10) has smaller sculpturing elements, shorter laesurae, and is additionally finely granulate. The species is named for Dr. D. J. Gobbett of the Sedgwick Museum, Cambridge. Verrueosisporites eximius sp. nov. Plate 80, figs. 5-8; text-fig. 5 d Diagnosis. Spores radial, trilete, originally spherical; amb circular or subcircular. Laesurae distinct, straight, length three-quarters of, to almost equal to, amb radius; bordered by conspicuous, smooth lips extending 7-11 p on either side. Exine strongly and comprehensively sculptured with large, flat-topped, closely packed, non-overlapping verrucae, which are separated by a continuous fine network of channels (up to 0-5 p wide), i.e. constituting a negative microreticulum. Verrucae polygonal in surface view, 4-22 p in longest diameter; normally smooth, but occasionally sparsely punctate (corroded specimens). Equatorial margin undulating. Exine very thick (5-8-5/x, including sculpture). Dimensions (30 specimens). Equatorial diameter 52-88 p (mean 72 p). Holotype. Preparation P149A/36, 40-9 103-4. L.989. Locus typicus. Triungen (sample G1470), Spitsbergen; Lower Carboniferous. Description. Holotype 78 p; laesurae almost equal to spore radius; lips 8-5 p wide, same height as polygonal verrucae; exine 7 p in thickness. This species is characterized by its extremely thick, distinctively sculptured exine, together with pronounced develop- ment of lips. Subinfraturma nodati Dybova and Jachowicz 1957 Genus lophotriletes (Naumova) Potonie and Kremp 1954 Type species. L. gibbosus (Ibrahim) Potonie and Kremp 1 954. Affinity. Unknown. Lophotriletes coniferus Hughes and Playford 1961 Plate 79, fig. 17 Dimensions (27 specimens). Equatorial diameter 69-105 p (mean 89 p). Genus anapiculatisporites Potonie and Kremp 1954 Type species. A. isselburgensis Potonie and Kremp 1954. Affinity. According to Potonie and Kremp (1955, p. 81) the genus may possibly be allied to the Filices. Anapiculatisporites concinnus sp. nov. Plate 80, figs. 9-12 Diagnosis. Spores radial, trilete; amb triangular with rounded apices and convex to 588 PALAEONTOLOGY, VOLUME 5 almost straight sides. Laesurae distinct, simple, more or less straight, length three- quarters to four-fifths spore radius. Proximal surface laevigate. Distal surface bearing scattered, small, uniform coni, 1—2 /x in length and 1—1*5 yu. in basal diameter. Coni about 2-3 p apart, fairly evenly distributed, but characteristically absent or markedly reduced in numbers at and around equatorial margin, particularly of interradial areas. Exine (excluding projections) about 1 p thick; rarely folded. Equatorial margin mainly smooth with only a few projecting coni, and these generally in the vicinity of the triangular apices. Dimensions (50 specimens). Equatorial diameter 23-44 p (mean 32 p). Holotype. Preparation P145C/1, 23-6 1009. L.994. Locus typicus. Triungen (sample G1466), Spitsbergen; Lower Carboniferous. Description. Holotype 35 p; laesurae equal three-quarters spore radius; distal coni 1 p broad at base, about 1-5 p long, 2-4 p apart, whole of proximal surface together with marginal interradial portions of distal surface entirely laevigate; twelve coni project from equator (four around each apex); margin otherwise smooth. Comparison. This species is similar to Granulatisporites? dumosus Staplin 1960 (p. 16; pi. 3, figs. 15-17), which, however, differs principally in possessing spines that are ‘largest along interradial portions of the equator’ and ‘reduced to granulations or absent at radial corners’; G.? dumosus should be assigned to Anapieulatisporites. In com- parison with Anapieulatisporites concinnus sp. nov., A. hispidus Butterworth and Williams 1958 (p. 364; pi. 1, figs. 30, 31) has more prominent spinose ornamentation of different distribution, whilst Azonotriletes cystostegius Andrejeva (in Luber and Waltz 1941, p. 17; pi. 2, fig. 29) is sculptured with small, rounded tubercles. Acanthotriletes microspinosus(non Ibrahim) Ishchenko 1958 (pp. 46-47; pi. 3, fig. 39) may be conspecific, at least in part, with Anapieulatisporites concinnus. EXPLANATION OF PLATE 80 All figures x 500 unless otherwise specified; from unretouched negatives. Figs. 1-4. Verrucosisporites gobbettii sp. nov. 1, Holotype; distal surface. 2, Sub-polar view; prepara- tion P226/2, 47-6 102-2 (L.985). 3, Proximal surface; preparation P181/2, 41-2 104-9 (L. 986). 4, Distal surface; preparation P176B/1, 27-7 112-9 (L.987). Figs. 5-8. V. eximius sp. nov. 5, 6, Holotype; proximal and distal surfaces respectively. 7, Sub-polar view; preparation P149A/11, 40-6 103-8 (L.990). 8, Proximal surface; preparation P149A/2, 46-8 106-3 (L.991). Figs. 9-12. Anapieulatisporites concinnus sp. nov. 9, Holotype; distal surface. 10, Proximal surface; preparation P145B/37, 40-2 103-0 (L.995). 11, Proximal surface; preparation P164/3, 31-7 97-4 (L.997). 12, Distal surface; preparation P145B/2, 50-4 95 0 (L.996). Fig. 13. Hystricosporites sp. Distal surface; preparation P164/1, 22-5 110-0 (L.1009). Figs. 14, 15. Acanthotriletes multisetus (Luber) Potonieand Kremp 1955. 14, Proximal surface; prepara- tion PI 75/2, 20-3 110-9 (L.1005). 15, Distal surface; preparation PI 63/ 1 , 26-8 113-2 (L.1006). Figs. 16-19. Anapieulatisporites serratus sp. nov. 16, Holotype; distal surface. 17, Closely spaced distal spinae having characteristic hexagonal bases, x 1,000; preparation P145A/1, 44-8 108-4 (L.1000). 18, Distal surface; preparation P149A/2, 45-7 107-1 (L.1001). 19, Distal spinae, x 1,000; preparation P145C/2, 40-2 113-3 (L.1002). Palaeontology, Vo/. 5 PLATE 80 PLAYFORD, Lower Carboniferous microspores G. PLAYFORD: LOWER CARBONIFEROUS MICROSPORES 589 Anapiculatisporites serratus sp. nov. Plate 80, figs. 16-19; text-fig. 5/ 1938 Zonotriletes curiosus ( partim ) Waltz in Luber and Waltz, pi. A, fig. 13 (non pi. 4, fig. 49). Diagnosis. Spores radial, trilete; amb subtriangular with straight to slightly convex sides and rounded apices. Laesurae indistinct to perceptible, simple, straight, almost reaching to equatorial margin. Proximal surface laevigate. Distal surface strongly and uniformly sculptured with closely packed, broadly based, sharply tapering spines, which are also evident at the equator (projecting as a conspicuous pseudo-flange). Spines have characteristically hexagonal bases (diameter 2—4 /x) and range in length from 2-5 to 6 p; somewhat diminished in size and density around the triangular apices. Exine (excluding spinae) 1—1*5 /u, thick. Dimensions (15 specimens). Equatorial diameter (excluding spinae) 38-61 p (mean 49/*). Hoiotype. Preparation P149A/3, 27 0 109-2. L.999. Locus typicus. Triungen (sample G1470), Spitsbergen; Lower Carboniferous. Description. Elolotype 42 p, convexly subtriangular. The species is characterized by its sculpture of strongly developed spines, which have distinctive hexagonal basal outlines (as seen in surface view) together with exclusively distal and equatorial distribution. Remarks. The second spore figured in Luber and Waltz 1938 (pi. A, fig. 13) as Zone - triletes curiosus Waltz is almost certainly conspecific with Anapiculatisporites serratus sp. nov. ; it undoubtedly represents a different species from the spore initially illustrated as Zonotriletes curiosus Waltz (in Luber and Waltz 1938, pi. 4, fig. 49) which, as repro- duced in Luber and Waltz 1941 (pi. 5, fig. 79), has been utilized subsequently (Ishchenko 1956, 1958) as the reference type for Z. curiosus. Comparison. Procoronaspora williamsii Staplin 1960 (p. 17; pi. 3, fig. 22) is smaller and has shorter laesurae; its spines are shorter at the distal pole, and do not possess the distinctive hexagonal bases of Anapiculatisporites serratus. Genus apiculatisporis Potonie and Kremp 1956 Type species. A. aculecitus (Ibrahim) Potonie 1956. Affinity. Unknown. Apiculatisporis macrurus (Luber) Potonie and Kremp 1955 Plate 81, fig. 3 1938 Azonotriletes macrurus Luber in Luber and Waltz, p. 30; pi. 7, fig. 94. 1952 Acanthotriletes macrurus (Luber) Ishchenko, p. 28; pi. 6, fig. 65. 1955 Apiculatisporites macrurus (Luber) Potonie and Kremp, p. 77. Description of specimens. Spores radial, trilete, originally spherical; amb circular to subcircular. Laesurae simple, length at least two-thirds spore radius; usually obscured by sculpture. Exine fairly thick, bearing prominent, somewhat variable, closely spaced 590 PALAEONTOLOGY, VOLUME 5 spines, which have more or less rounded apices, and are often fused at their bases; basal diameter of spines 3-6 ft, length 4-5-9 ft. Dimensions (20 specimens). Equatorial diameter 50-65 ft (mean 59 ft). Previous records. Reported previously from Russia only, as follows: from the Middle and Upper Carboniferous of the Donetz Basin (Luber and Waltz 1938, 1941; Ishchenko 1952); from Visean- Namurian of the western extension of the Donetz Basin (Ishchenko 1956); and from Visean-Bashkirian of the Dnieper-Donetz Basin (Ishchenko 1958). Genus acanthotriletes (Naumova) Potonie and Kremp 1954 Type species. A. ciliatus (Knox) Potonie and Kremp 1954. Affinity. W. and R. Remy (1957, p. 59; pi. 2, figs. 7-9) have recovered spores similar to Acanthotriletes from the Upper Carboniferous fern fructification Sphyropteris cf. boehnischi Stur. Acanthotriletes multisetus (Luber) Potonie and Kremp 1955 Plate 80, figs. 14, 15 1938 Azonotriletes multisetus Luber in Luber and Waltz, p. 23; pi. 5, fig. 61. 1955 Filicitriletes multisetus (Luber) Luber, pp. 55-56; pi. 3, fig. 52. 1955 Acanthotriletes multisetosus (Luber) Potonie and Kremp, p. 84. 1957 Acanthotriletes multisetus (Luber) Kedo, p. 1167. Description of specimens. Spores radial, trilete; equatorial outline circular to elliptical. Laesurae simple, obscure to perceptible, length approximately two-thirds spore radius. Exine thin (1-3 ft), commonly folded and torn; fine, dense sculpture of closely packed, minute projections which range from spinae to baculae and are evident at equator. Projections up to 1 ft in basal diameter and 2 ft in length, but usually considerably smaller. Dimensions (30 specimens). Equatorial diameter 42-78 ft (mean 60 ft). Comparison. Cyclogranisporites ampins McGregor 1960 (p. 26; pi. 11, fig. 8) is similar in general appearance, but larger and distinctly granulate. Previous records. Acanthotriletes multisetus has been reported previously by Luber and Waltz (1938, 1941) and Luber (1955) from the Visean of the Karaganda Basin; by Kedo (1957, 1958, 1959) from the Upper Tournaisian of White Russia; and recently by Love (1960) from the Lower Oil-shale Group (Visean) of Scotland. Acanthotriletes mirus Ishchenko 1956 Plate 81, figs. 1, 2 Description of specimens. Spores radial, trilete; amb circular to roundly subtriangular. Laesurae distinct, straight or slightly sinuous, length approximately equal to amb radius. Exine covered with numerous, evenly distributed, uniformly tapering spines, 4-8 ft high, 1-5-4 ft in basal diameter, and usually about 6ft apart; remainder of surface somewhat rough in appearance (infrapunctate or infragranulate). Exine thickness (excluding spines) 2-3 ft. Dimensions (12 specimens). Equatorial diameter 50-62 ft (mean 55 ft). G. PLAYFORD: LOWER CARBONIFEROUS MICROSPORES 591 Previous records. Ishchenko (1956, stratigraphical range table 1) found this species to be restricted to Tournaisian strata of the Donetz Basin (western extension). Genus hystricosporites McGregor 1960 Type species. H. delectabilis McGregor 1960. Discussion. This genus was instituted by McGregor (1960, p. 31) to incorporate sub- circular spores possessing a proximal and distal sculpture of more or less uniformly tapering appendages bearing distinctive anchor-like apical terminations. As implied by McGregor, such spores would have undoubtedly found inclusion within the broad connotation of Naumova’s (1953, p. 51) subgroup Archaeotriletes , which has since, however, been validated, emended, and thereby restricted by Potonie (1958, p. 30). McGregor discusses adequately the morphographical differences between Archaeo- triletes (Naumova) Potonie 1958, Nikitinisporites Chaloner 1959, Ancyrospora Richard- son 1960, and Hystricosporites , and they appear to represent clearly delineated generic units. Affinity. Naumova (1953, pp. 8, 51) noted the resemblance between Devonian spores of her subgroup Archaeotriletes, and those of the present-day water fern Azolla. However, this similarity is probably only superficial (see McGregor 1960, p. 32). Hystricosporites sp. Plate 80, fig. 13 Description of specimens. Spores radial, trilete; amb broadly roundly subtriangular to subcircular. Laesurae distinct, length about three-quarters spore radius; accompanied by narrow, slightly elevated and convoluted, lips. Distal surface and equatorial region of proximal surface bear long, uniformly tapering processes, which have grapnel-like tips; length of processes 12—21 /x, basal diameter 4— 6 p. Exine 5-7 p in thickness; micro- rugulate on proximal hemisphere, laevigate distally. Dimensions (3 specimens). Equatorial diameter (excluding appendages) 88-119^. Comparison. Azonotriletes ancistrophorus Luber (in Luber and Waltz 1941, p. 11; pi. 1, fig. 7; Luber 1955, p. 70; pi. 9, fig. 178), from the Upper Devonian and Lower Car- boniferous of the U.S.S.R., is somewhat smaller (50-80 p) and appears to lack a trira- diate mark. Remarks. The three spores described above, although insufficient to warrant the erection of a new species, represent an interesting new Lower Carboniferous occurrence of this distinctively sculptured group of spores, whose predominantly Devonian distribution is evident from Table 1 of McGregor (1960, p. 41). The only previous record from the Lower Carboniferous appears to be that of Azonotriletes ancistrophorus Luber, which occurs sparsely in Tournaisian strata of western Kazachstan (Luber 1955). Infraturma murornati Potonie and Kremp 1954 Genus convolutispora Hoffmeister, Staplin, and Malloy 1955 Type species. C. florida Hoffmeister, Staplin, and Malloy 1955. Affinity. Unknown. 592 PALAEONTOLOGY, VOLUME 5 Convolutispora tuber culata (Waltz) Hoffmeister, Staplin, and Malloy 1955 Plate 81, figs. 4, 5 1938 Azonotriletes tuberculatus Waltz in Luber and Waltz, p. 12; pi. 1, fig. 12, pi. 5, fig. 68, and pi. A, fig. 6. 1955 Verrucosisporites tuberculatus (Waltz) Potonie and Kremp, p. 66. 1955 Filicitriletes tuberculatus (Waltz) Luber, p. 54; pi. 2, figs. 45, 46. 1955 Convolutispora tuberculata (Waltz) Hoffmeister, Staplin, and Malloy, p. 384. 1956 Lophotriletes tuberculatus (Waltz) Ishchenko, p. 40; pi. 6, figs. 75, 76. Description of specimens. Spores radial, trilete, originally spherical; amb circular to subcircular. Laesurae simple, straight, length one-third to two-thirds spore radius, usually obscured by sculpture. Exine relatively thick, uniformly sculptured with low, more or less rounded, closely packed, anastomosing ridges or irregular rugulae-ver- rucae; lumina relatively insignificant, very irregular; muri roughly 1-5-4-5 p high, 2-5 p broad, highly variable. Equatorial margin undulating. Dimensions (50 specimens). Equatorial diameter 40-82 p (mean 60 p). Previous authors have recorded the following as equatorial diameter of this species: Waltz (in Luber and Waltz 1938), 50-90 p; Luber (1955), 60 p; Ishchenko (1956, 1958), 45-50 p. Comparison. The considerable variation, in both dimensions and sculpture, exhibited by this species was noted by Waltz (in Luber and Waltz 1938) and although not precisely documented, is evident from her illustrations of Azonotriletes tuberculatus , and also from the specimens observed by the present writer. Two species described from North American strata of Mississippian age, Convolutispora tessellata Hoffmeister, Staplin, and Malloy 1955 (p. 385; pi. 38, fig. 9) and C. punctatimura Staplin 1960 (p. 12; pi. 2, figs. 12, 20, 21) appear to fall within this range of variation and are therefore probably synonymous with C. tuberculata. Previous records. Convolutispora tuberculata has been reported by Luber and Waltz (1938, 1941) from the Lower Carboniferous of the Moscow, Kizel, and Karaganda Basins, and the Voronezh region; by Luber (1955) from the Lower Carboniferous of western Kazachstan; and by Ishchenko (1956, 1958) from Upper Devonian-Namurian rocks of the Dnieper-Donetz Basin. Thus the Spitsbergen specimens described above are the first of this species reported definitely outside Russia. EXPLANATION OF PLATE 81 All figures X 500, and from unretouched negatives. Figs. 1, 2. Acanthotriletes mirus Ishchenko 1956. 1, Distal surface; preparation P226/4, 26-8 112-6 (L.1007). 2, Proximal surface; preparation PI 48/1 , 46-1 101-5 (L.1008). Fig. 3. Apiculatisporis macrurus (Luber) Potonie and Kremp 1955. Distal surface; preparation PI 63/ 1 , 22-5 109-1 (L.1004). Figs. 4, 5. Convolutispora tuberculata (Waltz) Hoffmeister, Staplin, and Malloy 1955. 4, Sub-polar view; preparation P163/5, 18-4 110-7 (L. 1011). 5, Distal surface; preparation P163/4, 34-3 103-2 (L.1012). Figs. 6-9. C. harlandii sp. nov. 6, Holotype; proximal surface. 7, Distal surface; preparation P148/15, 41-2 100-7 (L.1016). 8, Proximal surface; preparation P148/3, 38-7 100-5 (L.1017). 9, Distal surface; preparation P163/2, 21-2 113-8 (L.1018). Figs. 10-12. C. crassa sp. nov. 10, Proximal surface; preparation PI 48/ 1 , 51-8 102-4 (L. 1021). 11, Holotype; distal surface. 12, Distal surface; preparation P148/2, 44-8 92-9 (L.1022). Palaeontology, Vol. 5 PLATE 81 PLAYFORD, Lower Carboniferous microspores G. PLAYFORD: LOWER CARBONIFEROUS MICROSPORES 593 Convolutispora vermiformis Hughes and Playford 1961 Plate 82, figs. 5, 6 1957 Convolutispora flexuosa forma minor Hacquebard, p. 312; pi. 2, fig. 10. Remarks. Spores recorded from Canada as Convolutispora flexuosa forma minor by Hacquebard (1957) and subsequently by McGregor (1960, p. 34; pi. 12, fig. 4) are con- sidered identical to the Spitsbergen specimens which were described by Hughes and Playford (1961, p. 30; pi. 1, figs. 2-4) as Convolutispora vermiformis. As the spores almost definitely represent a distinct species, the latter name is retained in preference to the infraspecific taxon. Dimensions (75 specimens). Equatorial diameter 47-86 p (mean 66 p). This corresponds closely to the size range of 47-81 p noted by McGregor (1960) and includes the measurement (72 p) stated by Hacquebard (1957). Comparison. Azonotriletes eancellothyris Waltz (in Luber and Waltz 1941, p. 15; pi. 2, fig. 19) may be similar, but its description is too brief for precise comparison. Previous records. Recorded previously from the Horton group (lowermost Mississippian) of Nova Scotia, Canada (Hacquebard 1957); from probable Upper Devonian of Melville Island, Canadian Arctic Archipelago (McGregor 1960); and from one sample (B685) of the Lower Carboniferous of Spitsbergen (Hughes and Playford 1961). Convolutispora clavata (Ishchenko) Hughes and Playford 1961 1956 Lophotriletes clavatus Ishchenko, p. 43; pi. 6, fig. 82. 1961 Convolutispora clavata (Ishchenko) Hughes and Playford, p. 31; pi. 1, figs. 7, 8. Dimensions (30 specimens). Equatorial diameter 94-126^ (mean 110p,). Previous records. Ishchenko (1956, 1958) described this species from Visean sediments of the Donetz Basin (western extension) and of the Dnieper-Donetz Basin. Hughes and Playford (1961) reported its occurrence in the Spitsbergen Lower Carboniferous (sample S59a). Convolutispora harlandii sp. nov. Plate 81, figs. 6-9; text-figs. 5 h,j Diagnosis. Spores radial, trilete; amb circular to subcircular, undulating. Laesurae distinct, simple, straight, length approximately two-thirds to three-quarters amb radius. Exine very thick (8-12 p, including muri). Distal hemisphere with pronounced, con- volute sculpture comprising a complex, tangled network of strongly developed, smooth, ramifying, sinuous, rounded muri, which are closely packed and overlapping; width of muri 6-10-5 p; lumina where delimited, irregular, usually elongate, up to 22 p in long- est diameter. Contact faces marked by three, discrete, interradial clusters of several, large, flattened, often fused, muri or rugulae-verrucae, which usually have a highly irregular outline in polar view; proximal hemisphere otherwise laevigate. Dimensions (66 specimens). Equatorial diameter 73-140 p (mean 106^). Holotype. Preparation PI 63/7, 58-3 100-2. L.1015. Locus typicus. Birger Johnsonfjellet (sample G1089), Spitsbergen; Lower Carboniferous. 594 PALAEONTOLOGY, VOLUME 5 Description. Holotype circular, diameter 100 p; laesurae two-thirds amb radius; exine 12 /n thick; distal surface with crowded, anastomosing ridges 6-3— 8-5 p wide; sculpture of proximal hemisphere restricted to contact areas, consisting of three relatively small, subequal areas, individually roughly 21 p x 17 p, resulting from the fusion of two or three low, irregular rugulae-verrucae. In some specimens included within this species, the muri in the equatorial region form a more or less continuous band (up to 18 p wide), which although simulating a cingulum is, in fact, part of the sculptural pattern of the distal hemisphere. This species is named for Mr. W. B. Harland, of the Sedgwick Museum, Cambridge. Convolutispora crassa sp. nov. Plate 81, figs. 10-12 Diagnosis. Spores radial, trilete; amb convexly subtriangular to circular, gently undulat- ing. Laesurae simple, straight, length two-thirds to three-quarters spore radius. Exine very thick (8-5—16 yu., including muri); comprehensive sculpture of closely spaced, relatively low, smooth, sinuous, flat-topped, non-overlapping muri, which both anas- tomose and terminate freely, constituting an imperfect reticulum. Breadth of muri highly variable (2-11 p), height 1 -5-3-5 p. Lumina irregular, often elongate, up to 20 p in longest diameter. Dimensions (35 specimens). Equatorial diameter 61-1 15 p (mean 85^). Holotype. Preparation P163/6, 37-3 99-3. L.1020. Locus typicus. Birger Johnsonfjellet (sample G1089), Spitsbergen; Lower Carboniferous. Description. Holotype 79 p, subcircular; laesurae approximately three-quarters amb radius; exine 10-5 yu. thick; muri 2—10 yu. wide, 2-5 p high; lumina 3-1 6p in longest diameter. The species is characterized by its exceptionally thick exine, which exhibits a distinctive, imperfectly reticulate sculpture. Comparison. Convolutispora crassa sp. nov. is probably conspecific with Zonotriletes planotubercu/atas Waltz (in Luber and Waltz 1941), but inadequate description (p. 21) EXPLANATION OF PLATE 82 All figures X 500, and from unretouched negatives. Figs. 1-3. Convolutispora labiata sp. nov. 1, Holotype; proximal surface. 2, Proximal surface; prepara- tion P158/7, 24-5 107-4 (L.1026). 3, Distal surface; preparation PI 58/ 10, 39 0 101-3 (L.1025). Figs. 4, 7, 8. C. usitata sp. nov. 4, Distal surface; preparation P149A/14, 39-9 102-6 (L.1029). 7, 8, Holotype; distal and proximal surfaces respectively. Figs. 5, 6. C. vermiformis Hughes and Playford 1961. 5, Proximal surface; preparation P161B/3, 42-7 95-4 (L.1013). 6, Distal surface; preparation P163/4, 21-1 105-6 (L. 1014). Fig. 9. Microreticulatisporites lunatus Knox 1950. Distal surface; preparation PI 75/ 1 , 32-4 92-9 (L. 1031). Fig. 10. Reticulatisporites rudis Staplin 1960. Proximal surface; preparation P145B/39, 38-5 103-7 (L.1036). Figs. 11-13. R. cancellatus (Waltz) comb. nov. 11, Sub-polar view; preparation P163/8, 39-9 104-4 (L.1038). 12, Distal surface; preparation P139/3, 52-9 109-4 (L.1037). 13, Sub-polar view; prepara- tion P163/4, 50-7 108-1 (L.1039). Palaeontology, Vol. 5 PLAATE 82 PLAYFORD, Lower Carboniferous microspores G. PLAYFORD: LOWER CARBONIFEROUS MICROSPORES 595 and illustration (pi. 4, fig. 50) preclude an accurate comparison. Further, Waltz (loc. cit.) and subsequently Ishchenko, 1956 (who transferred the species to Hymenozono- triletes Naumova) did not mention a variation to subtriangular shape, and they apparently considered the species to be a zonate form, rather than one possessing an exceptionally thick spore wall. It should be added, however, that few Russian workers express adequately the distinction between a cingulum or zona, and a thick exine as seen in polar view (cf. discussion herein of Stenozonotriletes). Previous records. The closely similar, if not identical, Russian species Zonotriletes planotuberculatus Waltz 1941 has been recorded by Luber and Waltz (1941) from the Lower Carboniferous of the Kizel region, and by Ishchenko (1956) who found it to be restricted to Tournaisian-Lower Visean strata of the western Donetz Basin. Convolutispora labicita sp. nov. Plate 82, figs. 1-3 Diagnosis. Spores radial, trilete ; amb circular to subcircular. Laesurae distinct, straight, length four-hfths of, to almost equal to, amb radius. Strongly developed, comprehensive sculpture of fairly closely spaced, rounded, smooth, sinuous muri, which both bifurcate and terminate freely. Width of muri irregular (range 3-12 p), height 2—5 /x; lumina rarely delimited. Prominent, more or less continuous lips result from radial alignment, and at least partial fusion, of muri in immediate vicinity of laesurae. Exine (including muri) 4-5-8 p thick. Equatorial margin undulating. Dimensions (20 specimens). Equatorial diameter 82-1 14 p (mean 99 p). Holotype. Preparation P158/8, 36 0 103-3. L.1024. Locus typicus. Birger Johnsonfjellet (sample G1092), Spitsbergen; Lower Carboniferous. Description. Holotype 90^; laesurae almost equal to spore radius, accompanied by mural lips (about 4p broad); convolute sculpture more strongly developed on distal surface but ridges remain non-overlapping; exine up to 6p thick. Comparison. Although similar with respect to size and lip development, Azonotriletes alveolatus Waltz (in Luber and Waltz 1941, pp. 15-16; pi. 2, fig. 21) differs from Con- volutispora labiata sp. nov. in having relatively narrow, uniform muri which coalesce to form a distinctly reticulate sculpture. Convolutispora usitata sp. nov. Plate 82, figs. 4, 7, 8 Diagnosis. Spores radial, trilete; originally spherical; amb circular or subcircular. Laesurae perceptible, simple, straight, length almost equal to spore radius. Exine 6-8 p thick, including dense, comprehensive sculpture of broad, rounded, crowded, frequently anastomosing muri, 4—10 wide and 2-4 p high; lumina highly irregular in shape and size, greatly subordinate to enclosing muri. Equatorial margin undulating to incised. Dimensions (20 specimens). Equatorial diameter 84-1 12 p (mean 100 p). Holotype. Preparation P149A/30, 36-7 102-5. L.1028. Locus typicus. Triungen (sample G1470), Spitsbergen; Lower Carboniferous. Qq C 674 596 PALAEONTOLOGY, VOLUME 5 Description. Holotype diameter 91 p; laesurae 41 p in length, discernible despite heavy exinal sculpture; exine 6-5 p thick (including muri). The species possesses the typically ‘convoluted’ sculpture of the genus Convolutispora ; its diagnostic features are large size, long laesurae, and strongly developed, ramifying muri. Comparison. In comparison with Convolutispora usitata sp. nov., C. cf. mellita Hoff- meister, Staplin, and Malloy (Butterworth and Williams 1958, p. 372; pi. 2, figs. 20, 21) has shorter laesurae together with higher muri, which often fuse to form locally ‘a thick, platy type of ornamentation’; C. finis Love 1960 (p. 115; pi. 1, fig. 7 and text-fig. 5) has much finer sculpture; and C. clavata (Ishchenko) Hughes and Playford 1961 (p. 31; pi. 1, figs. 7, 8) possesses shorter laesurae and less extensive, more verrucate sculpturing elements. Genus microreticulatisporites (Knox) Potonie and Kremp 1954 Type species. M. lacunosus (Ibrahim) Knox 1950. Affinity. Unknown. Microreticulatisporites lunatus Knox 1950 Plate 82, fig. 9 1948 Type 36K of Knox, fig. 41. 1950 Microreticulatisporites lunatus Knox, p. 320. Description of specimens. Spores radial, trilete; amb circular, sinuous. Laesurae simple, straight, not always evident, length approximately equal to amb radius. Regular microreticulate sculpture of muri 1-2 p wide and up to 1-5 p high, enclosing rounded to polygonal lumina 2-4 p in diameter. Exine (including muri) 2-3-5 p thick. Dimensions (36 specimens). Equatorial diameter 37-56 p (mean 45 p). The mean corresponds with the single measurement given by Knox (1950, p. 320). Previous records. From the Lower Carboniferous of Scotland (Knox 1 948 ; Butterworth and Williams 1958). Genus dictyotriletes (Naumova) Potonie and Kremp 1954 Type species. D. bireticulatus (Ibrahim) Potonie and Kremp 1954. Affinity. Unknown. Dictyotriletes caperatus sp. nov. Plate 83, figs. 3-5 Diagnosis. Spores radial, trilete; equatorial outline circular to subcircular. Laesurae distinct, straight, length three-fifths to two-thirds spore radius; often flanked by slightly raised, smooth, narrow lips about 2-5 p wide, decreasing in width equatorially. Exine sculptured with very fine, narrow, sinuous muri, which are very low, thread-like, anas- tomosing or freely terminating to comprise an open-meshed reticulum imperfectum, inconspicuous in relation to overall proportions; lumina where delimited are of highly variable, usually irregular shape, ranging from 3 to 19 p in diameter. Exine 3-5-6 p thick; sometimes additionally infrapunctate or infragranulate. G. PLAYFORD: LOWER CARBONIFEROUS MICROSPORES 597 Dimensions (40 specimens). Equatorial diameter 92-173 p (mean 131 p). Holotype. Preparation P148/10, 37-9 104-1. L.1032. Locus typicus. Triungen (sample G1472), Spitsbergen; Lower Carboniferous. Description. Holotype 156/x, amb elliptical due to compression; laesurae straight, ap- proximately three-fifths spore radius, with smooth, narrow (3ft) lips; exine finely, imperfectly reticulate, also infrapunctate; exine 4-5 p thick, not folded. Some specimens show one or two major folds. Sculptural details are apparent only under oil. Genus reticulatisporites (Ibrahim) Potonie and Kremp 1954 Type species. R. reticulatus Ibrahim 1933. Affinity. Spores conformable with Reticulatisporites have been recovered from Sclerocelyphus oviformis Mamay (1954, p. 82; pi. 21, figs. 7, 9). However, the systematic position of this Upper Carboniferous fructification is uncertain. Reticulatisporites rudis Staplin 1960 Plate 82, fig. 10 Description of specimens. Spores radial, trilete, originally spherical; amb circular to subcircular. Laesurae distinct, simple, length approximately two-thirds spore radius. Conspicuous reticulate sculpture of smooth, rounded muri (Ip broad at base, 2 p high) enclosing polygonal lumina (7-14 p in longest diameter). Exine (excluding muri) very finely granulate, 1-5-2 p thick. Dimensions (20 specimens). Equatorial diameter 59-73 p (mean 66 p). Previous records. From the Golata formation (Upper Mississippian) of Alberta, Canada (Staplin 1960). Reticulatisporites cancellatus (Waltz) comb. nov. Plate 82, figs. 11-13; Plate 83, figs. 1, 2 1884 ? Type 555 of Reinsch, p. 54; pi. 38, fig. 271. 1933 ?Type F6 of Raistrick, p. 5. 1938 Azonotriletes cancellatus Waltz in Luber and Waltz, p. 1 1 ; pi. 1, fig. 8 and pi. 5, fig. 73. 1955 Sphenophyllotriletes cancellatus (Waltz) Luber, pp. 41-42; pi. 4, figs. 18a, b, 79. 1955 Dictyotriletes cancellatus (Waltz) Potonie and Kremp, p. 108. 1956 Dictyotriletes cancellatus (Waltz) Ishchenko, p. 45; pi. 7, figs. 88, 89. 1957 Dictyotriletes cancellatus (Waltz) Naumova; Kedo, p. 1166. 1957 Reticulatisporites varioreticulatus Hacquebard and Barss, p. 17; pi. 2, figs. 15, 16. In discussing their new species Reticulatisporites varioreticulatus, Hacquebard and Barss (1957, p. 17) state justifiably that ‘it could be conspecific with Azonotriletes cancellatus Waltz 1938, but the brevity of the description precludes a definite assign- ment’. However, further description and illustration of this species given subsequent to Luber and Waltz (1938), by Luber (1955) and by Ishchenko (1956, 1958), clarifies and somewhat broadens the concept of Azonotriletes cancellatus, and as such includes Reticulatisporites varioreticulatus. Potonie and Kremp (1955, p. 108) listed A. cancellatus as a species of Dictyotriletes (Naumova) Potonie and Kremp. However, the prominent reticulate sculpture which is 598 PALAEONTOLOGY, VOLUME 5 often evident at the equator in the form of bastion-like projections (of. Luber 1955, pi. 4, fig. 78; Ishchenko 1956, pi. 7, fig. 88) indicates more appropriate inclusion within Reticulatisporites. Amplification of diagnosis. Spores radial, trilete; amb circular to subcircular. Laesurae usually distinct, length approximately two-thirds to three-quarters amb radius; bounded by flat, slightly elevated lips (3-6 p wide) having more or less straight outer margins. Prominent, comprehensive, fairly coarse, reticulate sculpture of smooth, rounded muri enclosing large, polygonal lumina. Muri 2-5— 6-5 p wide, up to 10^. high, frequently expanded at their junctions, usually clearly evident in optical section as conspicuous projections at equator. Width of lumina 6-40 p , typically variable on individual speci- mens. Thickness of exine (excluding muri) 2-6 p. Dimensions (100 specimens). Equatorial diameter 70—132 /x (mean 99^). This cor- responds closely to the size range of 75—1 30 yu. stated by Ishchenko (1956, 1958) for Dictyotriletes cancellatus (Waltz). Holotype. Plate 1, fig. 8 of Luber and Waltz 1938 (designated by Luber 1955). Locus typicus. Kizel region, Verkhani-Goubakhine mine, Kalinine shaft, bed 7 (after Luber and Waltz 1938; Luber 1955). Previous records. From the Lower Carboniferous of Russia (Luber and Waltz 1938, 1941, Luber 1955, Ishchenko 1956, 1958, and Kedo 1957, 1958), and of Canada (Hacquebard and Barss 1957). Ishchenko (1958, stratigraphical range table 3) indicates that the species ranges from Upper Devonian to Visean. Reticulatisporites planus Hughes and Playford 1961 Plate 83, figs. 6, 7 Dimensions (40 specimens). Equatorial diameter 63-104 p (mean 81 p). Based on an additional twenty-six specimens, this exceeds by 18 p the upper limit of the size range stated by Hughes and Playford (1961, p. 31). Reticulatisporites variolatus sp. nov. Plate 84, figs. 5-8; text-fig. 5 a Diagnosis. Spores radial, trilete; originally spherical; amb circular to subcircular. Laesurae distinct to perceptible, straight, length one-half to three-quarters spore radius; simple or accompanied by narrow lip development. Comprehensively sculptured with smooth, strongly developed muri of more or less uniform width (5-7 p) enclosing poly- gonal to irregularly rounded lumina ranging from 6 to 47 p in longest diameter. Muri EXPLANATION OF PLATE 83 All figures X 500, and from unretouched negatives. Figs. 1, 2. Reticulatisporites cancellatus (Waltz) comb. nov. 1, Distal surface; preparation PI 52/3, 44-4 111-8 (L.1041). 2, Proximal surface; preparation P148/3, 29-2 99 0 (L.1040). Figs. 3-5. Dictyotriletes caperatus sp. nov. 3, Holotype; proximal surface. 4, Proximal surface; prepara- tion PI 63/4, 49-7 93-9 (L.1033). 5, Sub-polar view; preparation P148/20, 34-7 106-1 (L.1034). Figs. 6, 7. Reticulatisporites planus Hughes and Playford 1961. 6, Proximal surface; preparation P226/3, 39-5 101-0 (L.1043). 7, Distal surface; preparation P148/2, 35-1 94-8 (L.1042). Palaeontology, Vol. 5 PLATE 83 PLAYFORD, Lower Carboniferous microspores G. PLAYFORD: LOWER CARBONIFEROUS MICROSPORES 599 4-8 p high, with characteristic clavate (mushroom-shaped) profile. Exine very thick (9-12 /la, exclusive of muri); laevigate to finely punctate. Dimensions (86 specimens). Equatorial diameter 77—124 yu. (mean 98 ft). Holotype. Preparation P165/3, 26-6 109-3. L.1044. Locus typicus. Blarevbreen (sample Q55), Spitsbergen; Lower Carboniferous. Description. Elolotype subcircular, 108 ft in diameter; simple laesurae 29 p long; coarsely reticulate with muri 6 ft high and 6-5 ft broad at top, enclosing lumina 10 ft- 30ft in longest diameter; exine 12ft thick, excluding muri. In some specimens the lumina on the proximal hemisphere are markedly larger than those enclosed distally. The exceptionally thick spore wall may simulate a definite equatorial structure; its true nature is apparent, however, from a study of specimens compressed in orientations other than polar. Comparison. Reticulatisporites speciosus Hacquebard and Barss 1957 (p. 18; pi. 2, fig. 17) is distinguishable on the basis of its exclusively distal, reticulate sculpture. Euryzono- triletes semirotundus (Waltz) Ishchenko 1956 (pp. 59-60; pi. 10, fig. 124) appears to re- present a different species from that described and illustrated initially (Waltz in Luber and Waltz 1941, p. 36; pi. 7, fig. 106), and may well be conspecific with Reticulatisporites variolatus sp. nov. Previous records. Possibly recorded by Ishchenko (as above) from Tournaisian/Visean strata of the western extension of the Donetz Basin. Reticulatisporites peltatus sp. nov. Plate 84, figs. 1-4 Diagnosis. Spores radial, trilete; originally spherical; amb circular to subcircular. Laesurae simple, straight, length almost equal to body radius; often obscured by sculp- ture. Exinal sculpture coarsely reticulate with smooth, rounded muri (2-5-5 p wide and 2-3 /x high) enclosing irregularly polygonal lumina 6-46 p in longest diameter (average 14 ft). Numerous, conspicuous, peltate (mushroom-like) processes are developed on, and characteristically at junctions of, the muri; processes 6-15 p long (average 8 p), 4-6-5 p broad at base, (expanded) apices 5—13 ft in diameter; profile clearly evident at equator. Exine (exclusive of sculpture) 3 -5-4-5 p thick. Dimensions (30 specimens). Equatorial diameter (excluding processes) 50-105 p (mean lip). Holotype. Preparation P167B/14, 36-2 102-9. L.1048. Locus typicus. Birger Johnsonfjellet (sample G1098), Spitsbergen; Lower Carboniferous. Description. Holotype subcircular, body diameter 90 p, laesurae distinct and long; muri 5 p broad, 3 p high; peltate processes up to 10 p long and 11 ft wide at top; exine (excluding sculpture) 4 p thick. Width of muri and length of processes are typically fairly uniform on any one specimen. Comparison. This species is similar in construction to Raistrickia boleta Staplin 1960 600 PALAEONTOLOGY, VOLUME 5 (p. 14; pi. 2, figs. 25, 27), but differs in being more definitely and regularly reticulate, and in possessing longer laesurae together with less coarse, more uniform, and generally shorter accessory projections. Closer comparison is difficult, however, owing to the brevity of Staplin’s description, and the evident corrosion of his illustrated specimens. Reticulatisporites? sp. Plate 85, figs. 1, 2 Description of specimens. Spores radial, trilete. Equatorial outline of body subtriangular with concave sides and rounded apices; interradial concavity often pronounced. Laesurae distinct, simple, straight, length approximately three-quarters body radius. Com- prehensively sculptured with very high, narrow, membranous muri which ramify to form an irregular, wide-meshed reticulum. Equatorial muri simulate a broad flange extending outwards as much as 32 g; proximal and distal muri flattened due to com- pression. Muri approximately 1 p wide; their greater part frequently lost in preservation and/or preparation, but junctions often persist as saetae-like projections. Exine (ex- cluding sculpture) 3-5-5 g around apices, 2-3 /i, elsewhere. Dimensions (9 specimens). Equatorial diameter of body 59-66 g (mean 63 g). Remarks. This unusual species appears distinct from any previously described re- presentatives of the Murornati. Its inclusion within Reticulatisporites is tentative, since it is not entirely conformable with that genus. Although not stated in the formal emenda- tion (Potonie and Kremp 1954, p. 144) of Reticulatisporites , most authors (e.g. Schopf, Wilson, and Bentall 1944, p. 44; Hoffmeister, Staplin, and Malloy 19556, p. 395; Bhardwaj 1957, p. 121) consider circular or subcircular amb as a diagnostic attribute of the genus. Moreover, the exceptionally high, membranous muri together with slight exinal thickening at the apices seem unusual for Reticulatisporites. Thus the erection of a new genus may later become justified, dependent upon the discovery of further speci- mens similar, if not identical, to those described above. The nine specimens here re- corded are, however, considered insufficient for the institution of even a formally named species. Similarity exists between this species and spores of the Selaginella megastachys group figured by Knox (1950, pi. 12, figs. 90-97). Genus foveosporites Balme 1957 Type species. F. canalis Balme 1957. Discussion. This genus was instituted by Balme (1957, p. 17) for the reception of circular or roundly triangular trilete spores possessing a sculpture of ‘pits or short channels EXPLANATION OF PLATE 84 All figures X 500, and from unretouched negatives. Figs. 1-4. Reticulatisporites peltatus sp. nov. 1, 2, Holotype; distal and proximal surfaces respectively. 3, Distal surface; preparation P145B/41, 37-6 102-7 (L.1049). 4, Distal surface; preparation PI 79/ 1 , 33-2 102-8 (L.1050). Figs. 5-8. R. variolatus sp. nov. 5, 6, Flolotype; distal and proximal surfaces respectively. 7, Distal surface; preparation P165/3, 54-4 97-9 (L.1045). 8, Proximal surface; preparation P165/2, 43-7 101-6 (L.1046). Palaeontology, Vol. 5 PLATE 84 PLAYFORD, Lower Carboniferous microspores G. PLAYFORD: LOWER CARBONIFEROUS MICROSPORES 601 irregularly distributed’. Although the type species is from the Mesozoic (of Western Australia), there is no justification for erecting a new genus to include Palaeozoic spores, such as the species described below, which conform with the diagnosis of Foveosporites. Affinity. Balme (loc. cit.) has pointed out the resemblance between F. canal is and spores of the Lycopo- dium verticillatum group, which were described and illustrated by Knox (1950, pp. 227-8; pi. 9, figs. 44-48). Foveosporites insculptus sp. nov. Plate 85, figs. 3-5 Diagnosis. Spores radial, trilete; amb circular to subcircular; originally spherical. Laesurae distinct, simple, straight or slightly curved, length three-fifths to four-fifths spore radius. Exine has prominent, comprehensive sculpture of sharply defined, ir- regularly distributed punctae, together with very narrow grooves, which often bifurcate but never coalesce to the extent of constituting a negative reticulum; depth of incise- ment up to 2 p. Thickness of exine 3-5-5 p. Equatorial margin slightly indented. Dimensions (35 specimens). Equatorial diameter 63-97 p (mean 78 p). Holotype. Preparation P149A/7, 35-8 102-3. L.1054. Locus typicus. Triungen (sample G1470), Spitsbergen; Lower Carboniferous. Description. Elolotype 71 p, circular; laesurae 28 p long; exine 4 p thick, with charac- teristic, discontinuous, punctate/vermiculate sculpture. Comparison. This species is distinguishable from Punctatisporites parvivermiculatus sp. nov. in its relatively coarse sculpture and thicker exine. Another similar species occurring in the Spitsbergen material, Punctatisporites stabi/is sp. nov., is essentially punctate and has a thinner spore wall than Foveosporites insculptus sp. nov. Puncta- tisporites vermiculatus Kosanke 1950 (p. 19; pi. 2, fig. 4) has a thicker exine, rather indistinct laesurae, together with wider, more deeply incised grooves which appear to form a fairly well-developed network. Subturma perinotrilites Erdtman 1947 Genus perotrilites (Erdtman) ex Couper 1953 Type species. P. granulatus Couper 1953. Discussion. Balme and Elassell (1962, p. 20) assigned to their new genus Diaphanospora some Australian Upper Devonian spores which they stated ‘could be placed, on purely morphographic grounds, in the genus Perotriletes [s'/'c] (Erdtman) ex Couper’. The apparent absence of such perinate forms in the Permian and Triassic of Australia is not considered sufficient justification for their assignment to a form genus other than Pero- trilites. Perotrilites of Devonian age was reported earlier by McGregor (1960, p. 35). Affinity. Spores of the Recent Selaginella sibirica group figured by Knox (1950, pi. 11, figs. 76-82) appear conformable with Perotrilites. 602 PALAEONTOLOGY, VOLUME 5 Perotrilites perinatus Hughes and Playford 1961 Plate 85, figs. 6, 7 Dimensions (80 specimens). Diameter of spore body 44-90 p (mean 70 p .). Comparison. The spores figured and described briefly by Balme (1960, p. 29; pi. 4, figs. 18, 19) as Auroraspora sp., from the Laurel Beds (Lower Carboniferous) of the Fitzroy Basin, Western Australia, are perhaps conspecific with P. perinatus. Diaphano- spora riciniata Balme and Hassell 1962 (p. 22; pi. 4, figs. 1^1; text-fig. 5) has pronounced lip development and its central body wall is equatorially thickened. Perotrilites magnus Hughes and Playford 1961 Plate 85, fig. 8 Dimensions (55 specimens). Diameter of spore body 97—160 /x (mean 125 p). Turma zonales (Bennie and Kidston) R. Potonie 1956 Subturma auritotriletes Potonie and Kremp 1954 Infraturma auriculati (Schopf) Potonie and Kremp 1954 Genus triquitrites (Wilson and Coe) Potonie and Kremp 1954 Type species. T. arculatus Wilson and Coe 1940. Affinity. Definite evidence of the botanical affinity of this distinctive group of spores appears to be lacking. Schopf, Wilson, and Bentall (1944, p. 46) have suggested a possible filicean relationship. Triquitrites trivalvis (Waltz) Potonie and Kremp 1956 Plate 85, figs. 13, 14 1938 Zonotriletes trivalvis Waltz in Luber and Waltz, pp. 18-19; pi. 4, fig. 41. 1956 Triquitrites trivalvis (Waltz) Potonie and Kremp, p. 88. EXPLANATION OF PLATE 85 All figures X 500, and from unretouched negatives. Figs. 1, 2. Reticulatisporitesl sp. 1, Distal surface; preparation P145B/43, 39-6 99-0 (L.1052). 2, Proxi- mal surface; preparation P145C/4, 33-2 108-7 (L.1053). Figs. 3-5. Foveosporites insculptus sp. nov. 3, Proximal surface; preparation P164/6, 20 0 105-0 (L. 1055). 4, 5, Holotype; distal and proximal surfaces respectively. Figs. 6, 7. Perotrilites perinatus Hughes and Playford 1961. 6, Distal surface; preparation P172/3, 44-3 103-8 (L.1057). 7, Distal surface; preparation P163/7, 54-3 101-1 (L.1058). Fig. 8. P. magnus Hughes and Playford 1961. Proximal surface; preparation M811/2, 56-4 102-4 (L.1258). Figs. 9, 10. Triquitrites batillatus Hughes and Playford 1961. 9, Proximal surface; preparation P158/7, 25-5 106-2 (L.1062). 10, Proximal surface; preparation P158/7, 27-7 113-0 (L.1061). Figs. 11, 12. Tripartites complanatus Staplin 1960. 11, Proximal surface; preparation P034/1, 42-7 95-2 (L.1066). 12, Proximal surface; preparation P034/2, 31-3 94-5 (L.1067). Figs. 13, 14. Triquitrites trivalvis (Waltz) Potonie and Kremp 1956. 13, Proximal surface; preparation P180B/4, 21-0 95-5 (L.1059). 14, Proximal surface; preparation P166/4, 20-6 95-8 (L.1060). Figs. 15-17. Tripartites incisotrilobus (Naumova) Potonie and Kremp 1956. 15, Proximal surface; preparation P163/10, 34-2 102-1 (L.1064). 16, Proximal surface; preparation P145C/3, 20-9 104-3 (L.1063). 17, Distal surface; preparation P155/3, 37-6 94-0 (L.1065). Palaeontology, Vol. 5 PLATE 85 PLAYFORD, Lower Carboniferous microspores G. PLAYFORD: LOWER CARBONIFEROUS MICROSPORES 603 1956 Trilobozonotriletes trivalvis (Waltz) Ishchenko, p. 97; pi. 19, figs. 231-3. 1958 Tripartites incisotrilobus (Naumova) Potonie and Kremp; Butterworth and Williams, pp. 373-4; pi. 3, fig. 2 (? 3, 4). Description of specimens. Spores radial, trilete ; amb subtriangular. Laesurae distinct, straight, simple; length two-thirds of, to almost equal to, spore body radius. Spore body essentially laevigate; equatorial outline subtriangular with rounded apices and convex to slightly concave sides (often straight). Cingulum narrow interradially (about 2-4 p), greatly expanded around radial areas to form prominent auriculae. Outer margins of auriculae thickened, laterally expanded, smooth to crenulate; thus constituting well-defined, massive, cushion-like cappings averaging 30 p x 7 /x in polar view. Dimensions (30 specimens). Overall equatorial diameter 38—66 /x (mean 51 f); diameter of spore body 24 -44 p (mean 34 ju). Remarks. As noted by Potonie (1956, p. 55), Trilobozonotriletes Naumova apparently lacks type-species designation, and many forms assigned to this ‘sub-group’ by Russian authors, e.g. Trilobozonotriletes trivalvis (Waltz) Ishchenko 1956, are more correctly included within Triquitrites (Wilson and Coe). Butterworth and Williams (1958, p. 373) list Zonotriletes trivalvis Waltz as synony- mous with Tripartites incisotrilobus (Naumova) and subdivided the latter into two varieties ( incisotrilobus and trivalvis). As will be discussed below, none of the spores illustrated by Butterworth and Williams (1958, pi. 3, figs. 2-4) appears truly conformable with T. incisotrilobus. However, at least one of their figures (pi. 3, fig. 2), exhibiting well-defined, thickened, crenulate cappings to the auriculae together with narrow, interradial, cingulate development, is representative of T. trivalvis. Sullivan (1958, p. 132) relegated T. trivalvis to varietal status within his interpretation of Simozonotriletes intortus (Waltz). The single spore illustrated of this variety (Sullivan 1958, pi. 28, fig. 3, and text-fig. 9b) differs from T. trivalvis, by direct comparison with text-fig. 9a of Sullivan (reproduction of Luber and Waltz’s pi. 4, fig. 41) in the following respects. The cingulum is much more pronounced, particularly in the interradial areas; marginal auriculate thickenings are larger and of a different shape, lacking the distinc- tive ‘sausage-like’ aspect characteristic of T. trivalvis (Waltz); and the spore body has more strongly concave sides. It should be added that the numerous Spitsbergen representatives recorded herein conform more or less faithfully with the original description and illustration of T. trivalvis; morphographical deviations approaching Simozonotriletes intortus Waltz var. trivalvis Sullivan have not been observed. The species is appropriately assigned to Triquitrites rather than to Murospora (or Simozonotriletes) on the basis of its prominent, more or less smooth, undivided auriculae and strictly subordinate interradial cingulate development. Previous records. Luber and Waltz (1938, 1941) recorded this species from the Lower Carboniferous of the Moscow Basin, and Kizel, Selizharovo, Borovichi, and Voronezh regions, U.S.S.R. Subsequently, Ishchenko (1956, 1958) has reported its restriction to strata of Visean age, in the Donetz Basin (western extension) and the Dnieper-Donetz Basin, respectively. T. trivalvis is present also in the Scottish Nam- urian A assemblages described by Butterworth and Williams (1958). 604 PALAEONTOLOGY, VOLUME 5 Triquitrites batillatus Hughes and Playford 1961 Plate 85, figs. 9, 10 Dimensions (60 specimens). Overall equatorial diameter 45-73 p (mean 58 p ,); diameter of spore body 32-56 p (mean 43 p). Genus tripartites Schemel 1950 Type species. T. vetustus Schemel 1950. Affinity. Unknown. Tripartites incisotrilobus (Naumova) Potonie and Kremp 1956 Plate 85, figs. 15-17 1884 Type 363 of Reinsch, p. 36; pi. 3, fig. 39. 1938 Zonotriletes incisotrilobus (Naumova) Waltz in Luber and Waltz, p. 19; pi. 4, fig. 42, and pi. A, fig. 10. 1956 Tripartites incisotrilobus (Naumova) Potonie and Kremp, p. 92. 1956 Trilobozonotriletes incisotrilobus Naumova; Ishchenko, p. 94, pi. 18, fig. 220. 1960 Tripartites incisotrilobus (Waltz) Potonie and Kremp; Staplin, pp. 26-27; pi. 5, fig. 17. 1960 Tripartites golatensis Staplin, p. 27; pi. 5, figs. 15, 16. Description of specimens. Spores radial, trilete; amb subtriangular. Laesurae distinct, simple, more or less straight, length at least four-fifths spore body radius. Spore body subtriangular with slightly concave to slightly convex sides and rounded apices; laevigate to finely granulate. Prominent, expanded auriculae developed about apices of spore body, and connected interradially by narrow, smooth equatorial flange. Radial extremities of auriculae conspicuously fluted or lobed; sometimes markedly expanded in a tangential direction resulting in a recurved or reflexed outline. Equatorial girdle (auriculae and flange) much darker than spore body. Dimensions (50 specimens). Overall equatorial diameter 38-73 p (mean 53 p); diameter of spore body 27-54 p (mean 39 p). Remarks. The morphographical variation within Tripartites incisotrilobus (Naumova) was adequately illustrated by Luber and Waltz (1938, 1941), and is confirmed by the Spitsbergen specimens described above. T. golatensis Staplin 1960 (p. 27; pi. 5, figs. 15, 16) was distinguished from T. incisotrilobus in exhibiting ‘less pronounced expansion and reflexion of the girdle’ (Staplin, loc. cit.). However, the second specimen of T. incisotrilobus figured by Luber and Waltz (1938, pi. A, fig. 10), showing comparatively minor tangential expansion of the auriculae, seems to be very closely paralleled by T. golatensis Staplin, whose recognition as a distinct species is therefore considered un- justified. Butterworth and Williams (1958, pp. 373-4) included Zonotriletes trivalvis Waltz within Tripartites incisotrilobus (Naumova), and instituted two varieties within the latter species. However, the spores illustrated by these authors (pi. 3, figs. 2-4) possess fine auriculate crenulation and as such appear distinct from T. incisotrilobus. Previous records. Apparently widespread in Lower Carboniferous deposits of the Northern Hemisphere, this species has been reported previously from Russia (Luber and Waltz 1938, 1941, Ishchenko 1956, G. PLAYFORD: LOWER CARBONIFEROUS MICROSPORES 605 1958, Bludorov and Tuzova 1956, Byvsheva 1957, 1960, Kedo 1957, 1958, 1959, Loginova 1959), Canada (Staplin 1960), and Spitsbergen (Flughes and Playford 1961). Tripartites complanatus Staplin 1960 Plate 85, figs. 11,12 Description of specimens. Spores radial, trilete; amb concavely subtriangular. Laesurae distinct, simple, straight, length approximately one-half to two-thirds spore body radius. Spore body finely granulate; equatorial outline subtriangular with concave sides and very broadly rounded apices which bear well-defined, dark auriculae. Radial extremities of auriculae differentiated into three to six bluntly rounded processes (average 2 ft long); auriculae otherwise smooth, not connected interradially. Dimensions (25 specimens). Overall equatorial diameter 23-34 ft (mean 28 ft); diameter of spore body 18-25 ft (mean 22 ft). Comparison. This species is distinct from Tripartites vetustus Schemel 1950 (p. 243; pi. 40, fig. 11) which has longer laesurae, together with more extensive, plicated auriculae. Trilobozonotriletes terjugus Ishchenko 1956 (pp. 96-97 ; pi. 18, fig. 228) is larger and less distinctly auriculate than T. complanatus. Previous records. From the Golata formation (Upper Mississippian) of Alberta, Canada (Staplin 1960). Subturma zonotriletes Waltz 1935 Infraturma cingulati Potonie and Klaus 1954 Genus stenozonotriletes (Naumova) Potonie 1958 Type species. S. conformis Naumova 1953. Discussion. Obvious difficulties arise in attempting to distinguish true representatives of Stenozonotriletes from specimens of Punctatisporites (or Leiotriletes) having a relatively thick wall, which in polar view may simulate a narrow cingulum. It is necessary there- fore to examine all such specimens closely and critically before generic assignment. In the case of Stenozonotriletes (polar view) an optical section of the spore body wall should be visible along the inner margin of the cingulum. An examination of individual specimens (unmounted in glycerine) in various orientations (particularly equatorial aspect) is invaluable in determining the true morphological features. Affinity. Unknown. Stenozonotriletes facilis Ishchenko var. praecrassus Ishchenko 1956 Plate 86, fig. 1 Description of specimens. Spores radial, trilete; amb circular to subcircular, smooth. Distinct spore body and relatively narrow cingulum; entirely laevigate. Distinct, straight, simple laesurae equal two-thirds to three-quarters spore body radius. Cingulum slightly darker in colour than spore body; width 8*5—12 ft. (average 10 ft), more or less uniform on any one specimen. Dimensions (30 specimens). Overall equatorial diameter 68-108 ft (mean 85 ft); spore body diameter 51-87 ft (mean 66 ft). 606 PALAEONTOLOGY, VOLUME 5 Remarks. Apart from a somewhat broader size range, the specimens conform closely to the diagnosis given by Ishchenko (1956, p. 72; pi. 14, fig. 161). Previous records. Ishchenko (1956, stratigraphical range table 3) indicates Tournaisian, Visean, and Namurian occurrences for this variety. Stenozonotriletes stenozonalis (Waltz) Ishchenko 1958 Plate 86, figs. 2, 3 1938 Zonotriletes stenozonalis Waltz in Luber and Waltz, p. 16; pi. 3, fig. 34 and pi. A, fig. 14. 1958 Stenozonotriletes stenozonalis (Waltz) Ishchenko, p. 86; pi. 10, fig. 135. Description of specimens. Spores radial, trilete; equatorial outline convexly subtriangular to subcircular, smooth to slightly discontinuously dentate. Laesurae distinct, simple, straight or slightly sinuous, extending almost to spore body margin. Spore body finely granulate; sculpture usually more pronounced on distal surface. Cingulum uniform, laevigate; width averages one-sixth of spore body diameter. Dimensions (15 specimens). Overall equatorial diameter 58-67 p (mean 62 p); cingulum width 6-11 p (mean 8 p). Discussion. The description of this species given by Ishchenko (1958) is somewhat broader than the original diagnosis (Waltz in Luber and Waltz 1938) with respect to dimensions and equatorial outline, but that it probably does not exceed reasonable specific limits is suggested by the Spitsbergen specimens observed and described above. Hacquebard (1957, p. 314) provisionally assigned to Stenozonotriletes four specimens questionably referred to Zonotriletes stenozonalis Waltz. Earlier, Hacquebard and Barss (1957, p. 24) recorded two specimens as Cincturasporites cf. Z. stenozonalis (Waltz, 1938) which from the description and illustration appear to be very doubtful representatives of S. stenozonalis. Previous records. Previous definite records from Tournaisian/ Visean of the Moscow Basin (Luber and Waltz 1938, 1941), and from Upper Devonian/Lower Carboniferous of the Dnieper-Donetz Basin (Ishchenko 1958). Stenozonotriletes simplex Naumova 1953 Plate 86, fig. 10 Description of specimens. Spores radial, trilete; amb convexly subtriangular. Spore body encompassed by conformable, narrow (2-4 p) cingulum. Entirely laevigate. Laesurae simple, straight, extending to margin of spore body. Dimensions (30 specimens). Overall equatorial diameter 40-63 p (mean 53 p). Previous records. Naumova (1953) and Ishchenko (1956) report this species from the U.S.S.R. and both note its stratigraphical distribution as Palaeozoic/Mesozoic. Stenozonotriletes inductus Ishchenko 1956 Plate 86, figs. 6, 7 Description of specimens. Spores radial, trilete ; amb subcircular to roundly subtriangular. Spore body surface of slightly roughened appearance. Very narrow cingulum (2-4-5 p) G. PLAYFORD: LOWER CARBONIFEROUS MICROSPORES 607 somewhat darker in colour than spore body; equatorial margin dentate. Laesurae distinct, simple, straight to slightly sinuous, length at least two-thirds spore body radius. Dimensions (30 specimens). Overall equatorial diameter 36-54 /x (mean 44 p). Previous records. According to Ishchenko (1956) this species is restricted, in the western extension of the Donetz Basin, to sediments of Tournaisian age. Stenozonotriletes darns Ishchenko 1958 Plate 86, figs. 4, 5 Dimensions (50 specimens). Overall equatorial diameter 47-80 p (mean 62 /x); width of cingulum 4-7 ^x (mean 5 p). Previous records. S. clarus was described initially from Upper Devonian, Tournaisian, and Visean strata of the Dnieper-Donetz Basin (Ishchenko 1958). Hughes and Playford (1961) reported some representatives of the species in one sample (B685) of the Spitsbergen Lower Carboniferous. Stenozonotriletes perforatus sp. nov. Plate 86, figs. 8, 9; text-fig. 5e Diagnosis. Spores radial, trilete; amb convexly subtriangular, smooth. Laesurae distinct, simple, straight or slightly sinuous; length three-quarters of, to slightly less than, the spore body radius. Spore body finely punctate, margin conformable with equator. Cingulum narrow, uniform, laevigate. Dimensions (35 specimens). Overall equatorial diameter 58-73 /x (mean 65 /x); width of cingulum 3—6-5 /x (mean 4-5 p). Holotype. Preparation PI 73/3, 51-4 95-2. L.1076. Locus typicus. Citadellet (sample G1446), Spitsbergen; Lower Carboniferous. Description. Holotype subtriangular with convex sides and rounded apices, 64 p overall ; spore body distinctly and finely punctate, diameter 52 p; cingulum laevigate, 6 p in width; laesurae prominent, slightly sinuous, length almost equal to spore body radius. Comparison. Stenozonotriletes stenozonalis (Waltz in Luber and Waltz 1938, p. 14; pi. 3, fig. 34 and pi. A, fig. 14) Ishchenko 1958 has granulate sculpture, but is otherwise similar. Stenozonotriletes cf. spetcandus Naumova 1953 Plate 86, fig. 1 1 Description of specimens. Spores radial, trilete; amb roundly subtriangular, more or less conformable with body outline. Spore body and cingulum laevigate (corroded specimens irregularly punctate). Laesurae distinct, straight, equal to, or slightly less than, spore body radius; bordered by smooth, elevated lips, individually 6-9 p broad. Dimensions (12 specimens). Overall equatorial diameter 56-88 p (mean 70 p); width of cingulum 6-9 p (mean 7 p). Comparison. The above specimens are insufficient to warrant definite assignment to Stenozonotriletes spetcandus which Naumova (1953) described from Upper Frasnian 608 PALAEONTOLOGY, VOLUME 5 deposits of the Voronezh region, U.S.S.R. In her brief description Naumova stated a size range of 55-65 g, which is exceeded considerably by these Spitsbergen specimens. Genus murospora Somers 1952 1952 Murospora Somers, p. 20. 1954 Simozonotriletes (Naumova 1939) ex Potonie and Kremp, p. 159; pi. 12, fig. 53. 1958 Simozonotriletes Potonie and Kremp; Sullivan, pp. 126-7. 1958 Westphalensisporites Alpern, p. 78. Type species. M. kosankei Somers 1952. Discussion. As noted recently by Staplin (1960, pp. 28-29) there appears to be little doubt concerning the synonymy of the genera Murospora Somers, Simozonotriletes (Naumova), and Westphalensisporites Alpern. Their diagnoses embrace morphogra- phically similar, cingulate microspores which are distinctly triangular in equatorial outline; the cingulum is often somewhat irregular, showing noticeable variations in width and/or thickness. Certainly, the spores described as Westphalensisporites ir- regularis Alpern 1958 (p. 78; pi. 1, figs. 15-17), with generally broad, flat cingula and apparent stratigraphical restriction to the Westphalian D, can scarcely be considered sufficient basis for the erection of a genus morphographically distinct from Murospora (or Simozonotriletes). Of the latter two genera, Murospora has the priority, since its formal institution preceded the validation (by Potonie and Kremp 1954) of Naumova’s 1939 ‘sub-group’ Simozonotriletes. Affinity. Unknown. EXPLANATION OF PLATE 86 All figures X 500, and from unretouched negatives. Fig. 1. Stenozonotriletes facilis Ishchenko var . praecrassus Ishchenko 1956. Proximal surface; prepara- tion P148/43, 38-8 107-0 (L.1068). Figs. 2, 3. S. stenozonalis (Waltz) Ishchenko 1958. 2, Proximal surface; preparation PI 73/1 , 53-6 94 0 (L.1069). 3, Proximal surface; preparation P173/2, 38-3 94-9 (L.1070). Figs. 4, 5. S. clarus Ishchenko 1958. 4, Proximal surface; preparation P226/2, 48-1 103-7 (L. 1074). 5, Proximal surface; preparation P226/1, 29-4 99-1 (L.1075). Figs. 6, 7. S. inductus Ishchenko 1956. 6, Proximal surface; preparation P169/3, 45-2 98-7 (L.1072). 7, Proximal surface; preparation PI 69/1 , 46-7 100-3 (L.1073). Figs. 8, 9. S. perforatus sp. nov. 8, Holotype; distal surface. 9, Proximal surface; preparation P226/3, 32-8 107-9 (L.1077). Fig. 10. S. simplex Naumova 1953. Proximal surface; preparation P171A/2, 39-5 104-6 (L.1071). Fig. 1 1. A. cf. spetcandus Naumova 1953. Proximal surface; preparation P148/65, 37-4 106-5 (L.1079). Figs. 12, 13. Murospora intorta (Waltz) comb. nov. 12, Proximal surface; preparation P145B/40, 35-6 101-3 (L.1080). 13, Proximal surface; preparation P034/1, 31-8 94-6 (L.1081). Figs. 14, 15. M. conduplicata (Andrejeva) comb. nov. 14, Proximal surface; preparation P145B/3, 34-8 103-8 (L. 1 108). 15, Proximal surface; preparation P145C/4, 23-8 106-9 (L.1107). Fig. 16. M. tripulvinata Staplin 1960. Proximal surface; preparation P188/2, 19-3 110-9 (L.1116). Figs. 17-19. M. sublobata (Waltz) comb. nov. 17, Distal surface; preparation P163/1, 36-5 108-3 (L.1109). 18, Proximal surface; preparation P145A/2, 32-1 93-7 (L.l 111). 19, Distal surface; prepara- tion PI 48/4, 29-2 105-8 (L.l 110). Figs. 20, 21. M. strigata (Waltz) comb. nov. 20, Proximal surface; preparation P145B/1, 19-1 113-6 (L.l 114). 21, Proximal surface; preparation P145A/2, 44-1 96-8 (L.l 115). Fig. 22. M. dupla (Ishchenko) comb. nov. Proximal surface; preparation P201/1, 22-6 104-4 (L.l 112). Palaeontology, Vol. 5 PLATE 86 PLAYFORD, Lower Carboniferous microspores G. PLAYFORD: LOWER CARBONIFEROUS MICROSPORES 609 Murospora intorta (Waltz) comb. nov. Plate 86, figs. 12, 13 1938 Zonotriletes intortus Waltz in Luber and Waltz, p. 22 (no description); pi. 2, fig. 24. 1954 Simozonotriletes intortus (Waltz) Potonie and Kremp, p. 159. 1956 Simozonotriletes intortus (Waltz) Ishchenko, pp. 88-89; pi. 17, fig. 204. Description of specimens. Spores radial, trilete; amb subtriangular with concave sides and rounded apices, smooth, conformable with spore body outline. Laesurae distinct, simple, straight, length at least two-thirds spore body radius. Spore body laevigate to infragranulate. Cingulum well defined, laevigate; uniform or may be perceptibly thicker and/or broader about apices; inner margin often corroded. Dimensions (50 specimens). Overall equatorial diameter 50—82 /x (mean 65 p); diameter of spore body 33-57 p (mean 44 f). Remarks. In 1954 Potonie and Kremp designated Simozonotriletes intortus (Waltz) as the type species of Simozonotriletes (Naumova). The assignment of the species to Murospora is necessitated through generic priority (discussed above). Sullivan (1958) has described S. intortus (Waltz) Potonie and Kremp from the three discrete horizons (Middle Westphalian A, Upper Westphalian A, and Middle West- phalian B) in the British Upper Carboniferous. This author recorded interesting morphographical diversity within the species, and upon this basis proposed nine vari- eties. Some of these variations are exhibited by the Spitsbergen specimens. However, the continuous intergradation of the variants (principally width and thickening of cingulum) does not, in the present writer’s view, lend itself to morphographical subdivision, even at varietal level. Furthermore, from the evident corrosion of Sullivan’s illustrated speci- mens, and the absence of statistical information, it would seem that his proposed varieties and their postulated interrelationships within the species are of questionable significance and validity. As discussed previously, Sullivan has incorrectly equated his S. intortus var. trivalvis with Triquitrites trivalvis (Waltz) Potonie and Kremp. Previous records. Reinsch (1884) illustrated many spores conformable with Murospora intorta (Waltz) comb. nov. Since then the species has been reported from the Carboniferous by numerous workers, and particularly from the Lower Carboniferous. The highest known stratigraphical occurrence is from the Middle Westphalian B of Nottinghamshire, England (Sullivan 1958). Murospora aurita (Waltz) comb, nov., emend. Plate 87, figs. 1-6; text-figs. 6a-q, 7 1938 Zonotriletes auritus Waltz in Luber and Waltz, p. 17; pi. 2, fig. 23. 1956 Simozonotriletes auritus (Waltz) Potonie and Kremp, p. 109. 1957 Cincturasporites auritus (Waltz) Hacquebard and Barss, p. 23; pi. 3, fig. 1. 1957 Cincturasporites irregularis Hacquebard and Barss, pp. 25-26; pi. 3, fig. 9. 1960 Murospora varia Staplin, p. 30; pi. 6, figs. 16-18. 1960 Murospora sp. cf. M. varia Staplin, p. 30; pi. 6, fig. 19. Emended diagnosis. Spores radial, trilete; amb subtriangular to irregular; margin smooth to undulating. Laesurae distinct, straight, reaching spore body margin or almost so; bordered by more or less distinct, smooth, broad, slightly elevated lips, individually 610 PALAEONTOLOGY VOLUME 5 5 *n yjjj'. r G. PLAYFORD: LOWER CARBONIFEROUS MICROSPORES 611 3'5-6-5/x wide. Spore body well defined, subtriangular, with convex sides and pointed or rounded apices; laevigate. Cingulum laevigate; uniform, or showing marked varia- tion in width and/or thickness. Cingulate thickenings peripheral, commonly situated at one or more of amb apices, but placement often highly irregular; up to five in number on any one specimen. Dimensions (140 specimens). Overall equatorial diameter 45-94 p (mean 68 p); diameter of spore body 28-51 p (mean 39 p). Holotype (here designated). Plate 2, fig. 23 of Luber and Waltz (1938). Locus typicus. U.S.S.R.-Kizel region, New Kizel mines, oblique shaft 24, bed 4 (after Luber and Waltz 1938, p. 17). Remarks. The spores described above occur abundantly, often predominantly, in many of the samples examined from the Lower Carboniferous of Spitsbergen. Detailed study of the considerable diversity exhibited by the cingula of these specimens (occurring associated in any given sample) indicates that the variants (cingulum width and thick- ness) constitute a continuous morphographical series, the specific (or subspecific) subdivision of which appears neither warranted nor desirable. For this reason Zono- triletes auritus Waltz is here emended and thus given a somewhat broader diagnosis, enabling its valid reception of spores closely allied, indeed continuously linked, with that originally figured by Waltz (i.e. the holotype, designated herein). As such, the species now incorporates several previously described species (see synonymy above). Staplin (1960) described and illustrated a similar range of variation in his species Murospora varia, which is con specific with M. aurita (Waltz) as emended above. The same applies to Cincturasporites auritus (Waltz) Hacquebard and Barss 1957 and C. irregularis Hacquebard and Barss 1957. The species is entirely conformable with Murospora Somers 1952. An assignment to Cincturasporites Hacquebard and Barss 1957 is rejected on the grounds that the so- called ‘overlap’ of the cingulum (Hacquebard and Barss 1957, p. 21, fig. 2), which is a diagnostic feature of the latter genus, does not appear to be a constant attribute of M. aurita (Waltz). Potonie (1960, p. 57) has already noted the close similarity between Cincturasporites and Murospora (al. Simozonotriletes). Indeed, Cincturasporites appears to embrace the connotations of several other well-established genera, viz. Knoxisporites, Stenozonotri/etes, and Lophozonotri/etes, and its recognition as a distinct form-genus does not, at this stage, seem justified. Comparison. Murospora intorta (Waltz) shows similar cingulate variation to M. aurita text-fig. 6. Camera-lucida drawings; all magnifications X500. a-q, Murospora aurita (Waltz) comb, nov., emend. Illustrating characteristic morphographical variation of this species as represented in a single sample (G1092). a, Preparation PI 58/7, 41-9 1007 (L.1088). b, Preparation PI 58/7, 27-8 94-5 (L.1089). c, Preparation P158/7, 40-9 100 1 (L.1091). d, Preparation P158/4, 28 3 94-3 (L.1092). e. Preparation PI 58/6, 32-3 106-3 (L.1093). /. Preparation P158/7, 31-5 111-1 (L.1094). g, Preparation P158/6, 32-4 1 10 6 (L.1095). h, Preparation P158/5, 54-2 94 0 (L.1096). y, Preparation P158/4, 30-4 107-8 (L.1097). k, Preparation P158/4, 43 0 94 1 (L.1098). m, Preparation P158/4, 44-4 112-1 (L.l 101). n, Preparation P158/4, 25-2 103-3 (L.llOO).p, Preparation P158/5, 54-2 1 02-5 (L.1099). q , Preparation P158/7, 32-8 114-3 (L.l 102). r, Probable aberrant form of Murospora aurita, one of several observed in preparations of sample Q55, in which the typical representatives (as in a-q above) are the predominat- ing microfloral constituents; preparation P165/1, 42-8 95-7 (L.l 106). r r C 674 612 PALAEONTOLOGY, VOLUME 5 ^SPORE BODY \o V E R A L L text-fig. 7. Graphs showing variation in overall and spore body diameters of Murospora aurita (Waltz) comb, nov., emend, (based upon measurement of 140 specimens in full polar view). (Waltz) comb, nov., emend., but is distinguishable in having simple laesurae, together with a spore body which in equatorial outline is decidedly less roundly triangular. The cingulum of Zonotriletes sulcatus Waltz {in Luber and Waltz 1938, p. 18; pi. 2, fig. 20) shows distinct, concentric furrowing. Zonotriletes turgidus Waltz {in Luber and Waltz 1941, p. 22; pi. 4, fig. 53) is subcircular and has a narrow, uniform cingulum. Previous records. Reinsch (1884) figured many specimens conformable with Murospora aurita (Waltz), which were recovered from Russian Carboniferous sediments. Subsequently the species has been re- ported from the Lower Carboniferous of the Moscow Basin and Kizel, Selizharovo, Borovichi, and Voronezh regions, U.S.S.R. (Luber and Waltz 1938, 1941); from the Upper Mississippian of Canada G. PLAYFORD: LOWER CARBONIFEROUS MICROSPORES 613 (Hacquebard and Barss 1957, Staplin 1960); and from the Lower Carboniferous of Spitsbergen (Hughes and Playford 1961). Probable aberrant forms. A number of spores have been observed spasmodically which are strongly reminiscent of Murospora aurita (Waltz) with respect to overall size, characteristic cingulum variation, and development of lips, but differ in being distinctly monolete and in possessing an oval to elliptical spore body (see Plate 87, figs. 8, 9; text-fig. 6r). One form (Plate 87, fig. 7) intermediate between the trilete and monolete conditions provides good evidence that these spores in fact represent abnormal devia- tions from the albeit variable category of M. aurita. It is noteworthy that such forms invariably occur in assemblages marked by abundance (at least 5 per cent.) of M. aurita. The forms rarely attain 1 per cent, of the total M. aurita content. Based upon twenty-five measured specimens, the following is the observed size range: overall length 60-90 ft (mean 73 ft), width 42-67 ft (mean 56 ft); spore body length 38-62 p (mean 49ft), width 29-46 ft (mean 36 ft). The ‘aberrant’ forms have been noted in the following samples : G1098, G 1 102 (Birger Johnsonfjellet) ; G 1466 (Triungen) ; W217 (Adolfbukta, north shore); F20, G1278, G1276 (Anservika); M365, Q55 (Blarevbreen); G1339 (Margaretbreen); G636 (De Geerfjellet) ; R38 (Ragnarbreen). One of the figures given by Alpern (1958, pi. 1, fig. 18) of his species Densosporites major shows a large, elongate, cingulate spore which may possibly be monolete, whereas the other figure of the species (pi. 1, fig. 19) is of a roundly triangular, distinctly trilete spore. However, Alpern’s brief description contains no reference to the presence of monolete variants within the species. Divergence in the character of the tetrad mark is known within the spores of certain modern plants, such as Aspleniopsis and Marattia (see Erdtman 1957, p. 48, fig. 81; Harris 1955, p. 60). Murospora conduplicata (Andrejeva) comb. nov. Plate 86, figs. 14, 15 1941 Zonotriletes conduplicatus Andrejeva in Luber and Waltz, p. 38; pi. 7, fig. 113. 1956 Simozonotriletes conduplicatus (Andrejeva) Ishchenko, p. 89; pi. 17, figs. 206, 207. Description of specimens. Spores radial, trilete; entirely laevigate. Amb subtriangular with rounded apices and concave to almost straight sides. Laesurae distinct, simple, straight, length equal to, or slightly less than, spore body radius. Cingulum undiffer- entiated and uniform in width; often slightly darker in colour than spore body. Dimensions (60 specimens). Overall equatorial diameter 36-55 ft (mean 45 ft); diameter of spore body 25-39 ft (mean 32 ft). Previous records. This species was first described from the Lower Carboniferous of the Moscow Basin and Selizharovo district, U.S.S.R. (Andrejeva in Luber and Waltz 1941). It has recently been reported from Tournaisian/Visean sediments of the Donetz Basin (western extension) and Dnieper- Donetz Basin (Ishchenko 1956, 1958) and of the Volga-Ural region (Byvsheva 1960). Murospora sublobata (Waltz) comb. nov. Plate 86, figs. 17-19 1938 Zonotriletes sublobatus Waltz in Luber and Waltz, p. 17; pi. 2, fig. 22. 1956 Simozonotriletes sublobatus (Waltz) Potonie and Kremp, p. 110. 614 PALAEONTOLOGY, VOLUME 5 1957 Triquitrites tendoris Hacquebard and Barss, p. 18; pi. 2, figs. 18, 19. 1960 Murospora laevigata Staplin, pp. 29-30; pi. 6, fig. 21. Description of specimens. Spores radial, trilete; amb subtriangular with concave to straight sides and rounded apices. Laesurae distinct, length four-fifths of, to almost equal to, spore body radius; simple or occasionally with incipient lips. Spore body concavely subtriangular with rounded apices; laevigate to infrapunctate (corroded specimens irregularly punctate). Cingulum laevigate; perceptibly to markedly widened and thickened around spore body apices, but rarely to the extent of constituting well- defined valvae. A study of representatives of this species present in poorly preserved assemblages suggests that such differences in cingulum thickness, which might not otherwise be apparent, coupled with fine punctation of the spore body are, in fact, emphasized by corrosion. Dimensions { 60 specimens). Overall equatorial diameter 34-58^ (mean 47 p); diameter of spore body 22—38 /x (mean 30 f). Remarks. From an exhaustive study of approximately 150 specimens occurring in a variety of the Spitsbergen samples, it became clear that any apparently significant differences which may exist between specimens identical to Zonotri/etes sublobcitus Waltz, Triquitrites tendoris Hacquebard and Barss, and Murospora laevigata Staplin are negated by the presence of numerous intermediate forms. Accordingly the two latter species are here considered synonymous with Z. sublobcitus Waltz, the original description of which is sufficiently broad to accommodate both. The presence of a well- defined, continuous equatorial girdle indicates the correct assignment of the species to Murospora , rather than to Triquitrites. Comparison. Murospora conduplicata (Andrejeva) differs from M. sublobcita (Waltz) comb. nov. in possessing an undifferentiated cingulum of essentially uniform width. M. intorta (Waltz) is generally considerably larger, and the sides of its spore body are more sharply concave. The spores described by Sullivan (1958, pp. 130-1; pi. 26, figs. 10-12; text-figs. 5a , b) as Simozonotriletes intortus var. sublobatus (Waltz) are larger (66-5-80/x) and possess well-defined valvae; direct comparison is necessary to establish conspecificity with M. sublobata (Waltz). Previous records. Murospora sublobata (Waltz) has been recorded from Lower Carboniferous strata of the Moscow Basin, and Kizel, Selizharovo, Borovichi, and Voronezh regions, U.S.S.R. (Luber and Waltz 1938, 1941); and from the Upper Mississippian of Canada (Hacquebard and Barss 1957, Staplin 1960). Murospora dupla (Ishchenko) comb. nov. Plate 86, fig. 22; text-fig. 8a 1956 Simozonotriletes duplus Ishchenko, p. 93; pi. 17, fig. 216. Description of specimens. Spores radial, trilete; amb subtriangular with concave sides and broadly rounded apices. Laesurae distinct, simple, straight, length at least four- fifths spore body radius. Body laevigate; outline more or less conformable with equator, but sides may be more sharply concave. Cingulum laevigate; divided equally by clearly defined, continuous, narrow, shallow groove proximally incised parallel to equator. G. PLAYFORD: LOWER CARBONIFEROUS MICROSPORES 615 Dimensions (4 specimens). Overall equatorial diameter 72-82/x (mean 75^); diameter of spore body 40-45 ,u. (mean 43 p). Previous records. According to Ishchenko (1956) this species is restricted to Middle Visean strata of the Donetz Basin (western extension). Murospora strigata (Waltz) comb. nov. Plate 86, figs. 20, 21 ; text-fig. 8 b 1941 Zonotriletes strigatus Waltz in Luber and Waltz, p. 19; pi. 3, fig. 41. 1958 Simozonotriletes strigatus (Waltz) Ishchenko, p. 88; pi. 11, fig. 141. text-fig. 8. Camera-lucida drawings and generalized, hypothetical, polar sections, a. Murospora dupla (Ishchenko) comb, nov.; preparation P201/2, 40 1 1031 (L.1113). b, Murospora strigata (Waltz) comb, nov.; preparation P145A/2, 44 1 96-8 (L. 1115). e.e.=exoexine; i.e. = intexine; 1 =laesura. Magnifications x 500. Description of specimens. Spores radial, trilete; amb subtriangular with broadly rounded apices and concave sides. Laesurae distinct, simple, straight, length two-thirds of, to almost equal to, spore body radius. Spore body laevigate to very finely punctate; concavely subtriangular. Proximal surface of cingulum differentiated into three, sub- equal, concentric bands consisting of a smooth, fiat-topped, outer (equatorial) ridge separated from a similar inner ridge by a continuous channel of approximately the same width as the ridges; the inner ridge is situated at, or just equatorially beyond, the spore body margin. Distal surface of cingulum smooth. Dimensions (15 specimens). Overall equatorial diameter 60-82^ (mean 70^); diameter of spore body 36-46 p (mean 40 p). 616 PALAEONTOLOGY, VOLUME 5 Remarks. The specimens conform closely with the original description of Zonotri/etes strigatus given by Waltz (in Luber and Waltz 1941), who described the cingulum as ‘complex, consisting of two thick but flat rims between which is disposed a thinner, more transparent area’; Waltz noted the conformity of the cingulate elements with the spore body outline. Spores assigned to this species could conceivably have resulted from a widening (due to corrosion) of the narrow proximal groove characteristic of the cingulum in Mwospora dupla (Ishchenko). However, the generally well-preserved nature of the specimens ob- served, and the absence of intermediate forms, support the recognition of the two species as morphographically discrete. Comparison. Simozonotriletes trigonalis Ishchenko 1956 (p. 93; pi. 17, fig. 217) appears to possess lipped laesurae, but otherwise resembles Murospora strigata (Waltz) comb, nov. Previous records. This species was first described from Lower Carboniferous deposits of the Selizharovo region, U.S.S.R. (Luber and Waltz 1941). Recently, Ishchenko (1958) has reported its restriction, in the Dnieper-Donetz Basin, to sediments of Visean age. Murospora tripulvinata Staplin 1960 Plate 86, fig. 16 Description of specimens. Spores radial, trilete; amb concavely subtriangular. Laesurae distinct, simple, straight, length approximately four-fifths body radius. Spore body subtriangular with rounded apices and slightly concave to slightly convex sides. Cingulum narrow interradially; conspicuously expanded at radial corners to form prominent, rounded, subequal valvae. Spore body and cingulum laevigate. Dimensions (25 specimens). Overall equatorial diameter 49-62^. (mean 55 ft); diameter of spore body 32-48 ft (mean 39ft). Comparison. Triquitrites trivalvis (Waltz) Potonie and Kremp 1956 possesses well- EXPLANATION OF PLATE 87 All figures X 500, and from unretouched negatives. Figs. 1-6. Murospora aurita (Waltz) comb, nov., emend. 1, Proximal surface; preparation P167B/5, 37-7 103-9 (L.1082). 2, Proximal surface; preparation P167B/6, 38-5 105-5 (L.1083). 3, Proximal sur- face; preparation P167B/1, 40-4 99-9 (L.1084). 4, Proximal surface; preparation P167B/15, 40-4 102-8 (L.1085). 5, Proximal surface; preparation P145B/8, 35-6 103-6 (L.1086). 6, Proximal surface; preparation P188/1, 21 -7 104-2 (L.1087). Figs. 7-9. Probable aberrant forms of M. aurita (Waltz) comb, nov., emend., showing variation in laesurate character. 7, Preparation P165/3, 25-8 93-9 (L. 1 103). 8, Preparation P167B/12, 35-5 103-9 (L.1105). 9, Preparation P167B/1, 25-2 100-8 (L.1104). Figs. 10-12. M. friend'd sp. nov. 10, Holotype; proximal surface. 11, Proximal surface; preparation P145B/35, 37-8 103-7 (L. 1118). 12, Proximal surface; preparation P167B/2, 42-0 106-7 (L.1119). Fig. 13. Anulatisporites amdatus (Loose) Potonie and Kremp 1954. Distal surface; preparation P175/4, 20 1 95-9 (L.1121). Figs. 14, 15. A. labiatus Hughes and Playford 1961. 14, Proximal surface; preparation P172/2, 23-2 92-8 (L.l 122). 15, Lateral view; preparation P181/3, 22-9 101-4 (L.l 123). Palaeontology, Vol. 5 PLATE 87 PLAYFORD, Lower Carboniferous microspores G. PLAYFORD: LOWER CARBONIFEROUS MICROSPORES 617 defined thickenings around outer margins of auriculae, contrasting with the uniform lobate expansions of the cingulum in Murospora tripulvinata. Previous records. From the Golata formation (Upper Mississippian) of Alberta, Canada (Staplin 1960). Murospora friendii sp. nov. Plate 87, figs. 10-12 Diagnosis. Spores radial, trilete; amb subtriangular, generally conformable with spore body margin. Laesurae distinct, straight, reaching to inner margin of cingulum; ac- companied by very narrow (individually 1—1 *5/x broad), elevated (up to 2-5 // high) lips which often appear highly contorted due to compression. Spore body subtriangular with convex sides and pointed to rounded apices; laevigate to infrapunctate. Cingulum laevigate; width uniform or irregular on any one specimen; colour usually slightly darker than spore body. Equatorial margin smooth to undulating. Dimensions (40 specimens). Overall equatorial diameter 46-70//. (mean 57//); diameter of spore body 27-40// (mean 33//). Holotype. Preparation P188/3, 36-3 95-2. L.1117. Locus typicus. Birger Johnsonfjellet (sample G1102), Spitsbergen; Lower Carboniferous. Description. Holotype 63// overall, entirely laevigate; spore body diameter 32//; cingulum variable in width (range 10-19//); laesurate lips very narrow, sinuous. Comparison. Euryzonotriletes translaticius Ishchenko 1956 (p. 48; pi. 8, fig. 99) re- sembles Murospora friendii sp. nov., but differs in possessing simple, sinuous laesurae which do not reach the spore body margin, and in being constantly smaller (35-45//). According to Ishchenko (1956) the spore body exine of E. translaticius is frequently destroyed whilst the cingulum is comparatively thick, hence robust. The species is named for Mr. P. F. Friend, of the Sedgwick Museum, Cambridge. Genus anulatisporites (Loose) Potonie and Kremp 1954 Type species. A. anulatus (Loose) Potonie and Kremp 1954. Affinity. Unknown. Anulatisporites anulatus (Loose) Potonie and Kremp 1954 Plate 87, fig. 13 1932 Sporonites anulatus Loose in Potonie, Ibrahim, and Loose, p. 451 ; pi. 18, fig. 44. 1 934 Zonales-sporites ( Anulatisporites ) annulatus (Loose) Loose, p. 151. 1944 Densosporites annulatus (Loose) Schopf, Wilson, and Bentall, p. 40. 1954 Anulatisporites anulatus (Loose) Potonie and Kremp, p. 159; pi. 20, fig. 7. Description of specimens. Spores radial, trilete ; amb subcircular to roundly subtriangular. Laesurae obscure to perceptible, simple, reaching to inner margin of cingulum. Massive, uniform, laevigate cingulum much darker in colour than fragile, infragranulate spore body. 618 PALAEONTOLOGY, VOLUME 5 Dimensions (50 specimens). Overall equatorial diameter 36-63 /a (mean 48 /a); diameter of spore body 21—38 (mean 29/a). Comparison. The Scottish Lower Carboniferous species Densosporites pseudo annulatus Butterworth and Williams 1958 (pp. 379-80; pi. 3, figs. 42, 43), recorded also by Love (1960, p. 109), seems close to A. anulatus. Previous records. This species, described initially from the Westphalian of the Ruhr district (see Potonie and Kremp 1956u, p. 112; pi. 17, figs. 365-72) appears to have fairly extensive distribution within the Carboniferous. Dybova and Jachowicz (1957) record it from Upper Silesian coals ranging in age from Namurian A to Westphalian C; these authors list in the synonymy two Upper Carboni- ferous species of Kosanke (1950): Densosporites reynoldsburgensis and D. sphaerotriangularis. Smith (1960) notes the occurrence of A. anulatus in the Lower Coal Measures (Westphalian A) of Durham, England. Hacquebard and Barss (1957) describe it from Upper Mississippian coal of the South Nahanni River area, Northwest Territories, Canada. Anulatisporites labiatus Hughes and Playford 1961 Plate 87, figs. 14, 15 Dimensions (75 specimens). Overall equatorial diameter 71—136 /x (mean 102 /a); diameter of spore body 42-88 p (mean 62 /a); width of cingulum 12-30 /a (mean 20 /a). Comparison. This species resembles closely Murospora paenulata Staplin 1960 (p. 30; pi. 7, figs. 1-4) although the specimens figured by Staplin appear to be corroded. The principal difference, however, lies in the fact that ,4. labiatus possesses a definite cingu- lum in the usually accepted sense (Potonie and Kremp 1955, p. 15) whereas M. paenulata is said to have a ‘capsula’ (the precise definition of which is uncertain) as distinct from what Staplin terms a ‘true cingulum’. From Plate 87, fig. 15, illustrating a specimen of A. labiatus in equatorial aspect, it is evident that the exoexine shows a marked and abrupt centrifugal increase in thickness in the equatorial region, constituting a broad, massive, cingulate border to the spore body. In this respect it is similar to Cincturasporites Hacquebard and Barss (1957, fig. 2b), although the ‘overlap’ said to be characteristic of that genus is not represented. Staplin’s (1960) usage of the genus Murospora, without formal emendation, diverges considerably from the original diagnosis (Somers 1952) which is here accepted. Previous records. Described initially by Hughes and Playford (1961) from one sample (B685) of the Lower Carboniferous of Spitsbergen, this species was probably recorded as Zonotriletes macrodiscus Waltz (in Luber and Waltz 1938, 1941 : no description) from the Lower Carboniferous of the Moscow Basin, and Selizharovo and Borovichi regions, U.S.S.R. [To be concluded in Palaeontology, Vol. 5, Part 4] THE PALAEONTOLOGICAL ASSOCIATION COUNCIL 1962 President Professor T. Neville George, The University, Glasgow, W. 2 Vice-Presidents Professor O. M. B. Bulman, Sedgwick Museum, Cambridge Professor W. F. Whittard, The University, Bristol Dr. W. H. C. Ramsbottom, Geological Survey Office, Leeds Treasurer Professor P. C. Sylvester-Bradley, The University, Leicester Assistant Treasurer Dr. T. D. Ford, The University, Leicester Secretary Dr. C. H. Holland, Department of Geology, Bedford College, London, N.W. 1 Editors Mr. N. F. Hughes, Sedgwick Museum, Cambridge Dr. W. S. McKerrow, University Museum, Oxford Dr. Gwyn Thomas, Department of Geology, Imperial College of Science, London, S.W. 7 Other members of Council Dr. F. T. Banner, British Petroleum Company, Sunbury on Thames Dr. F. M. Broadhurst, The University, Manchester Dr. A. J. Charig, British Museum (Natural History), London Dr. L. R. Cox, British Museum (Natural History), London Dr. W. T. Dean, British Museum (Natural History), London Dr. C. Downie, The University, Sheffield Dr. R. Goldring, The University, Reading Dr. J. C. Harper, The University, Liverpool Dr. M. R. House, The University, Durham Dr. J. W. Neale, The University, Hull Dr. R. J. G. Savage, The University, Bristol Mr. J. J. D. Smith, Geological Survey and Museum, London Dr. C. D. Waterston, Royal Scottish Museum, Edinburgh Mr. C. W. Wright, London Overseas Representatives Australia: Professor Dorothy Hill, Department of Geology, University of Queensland, Brisbane Canada: Dr. D. J. McLaren, Geological Survey of Canada, Department of Mines and Technical Surveys, Ottawa India: Professor M. R. Sahni, Department of Geology, Panjab University, Chandigarh New Zealand: Dr. C. A. Fleming, New Zealand Geological Survey, P.O. Box 368, Lower Hutt West Indies and Central America: Dr. L. J. Chubb, Geological Survey Department, Kingston, Jamaica Eastern U.S.A.: Professor H. B. Whittington, Museum of Comparative Zoology, Harvard Uni- versity, Cambridge 38, Mass. Western U.S.A.: Dr. J. Wyatt Durham, Department of Paleontology, University of California, Berkeley 4, Calif. PALAEONTOLOGY VOLUME 5 • PART 3 CONTENTS The Palaeontology of the Namurian rocks of Slieve Anierin, Co. Leitrim, Eire. By the late Patricia j. yates 355 Further studies on micro-organisms and the presence of syngenetic pyrite. By LEONARD G. LOVE 444 The Silurian trilobite Encrinurus punctatus (Wahlenberg) and allied species. By R. p. tripp 460 Microplankton from the Ampthill Clay of Melton, South Yorkshire. By W. A. S. SARJEANT 478 Some Diplograptids from the British Lower Silurian. By g. h. packham 498 New ammonites from the Barremian of North Bulgaria. By j. r. manolov 527 Some Wenlockian fenestrate Bryozoa. By t. g. miller 540 Lower Carboniferous microfloras of Spitsbergen — Part I. By g. playford 550 PRINTED IN GREAT BRITAIN AT THE UNIVERSITY PRESS, OXFORD BY VIVIAN RIDLER, PRINTER TO THE UNIVERSITY VOLUME 5 • PART 4 Palaeontology FEBRUARY 1963 PUBLISHED BY THE PALAEONTOLOGICAL ASSOCIATION LONDON Price £3 THE PALAEONTOLOGICAL ASSOCIATION The Association was founded in 1957 to further the study of palaeontology. It holds meetings and demonstrations, and publishes the quarterly journal Palaeontology. Membership is open to individuals, institutions, libraries, &c., on payment of the appropriate annual subscription: Institutional membership . . . . £5. 5s. ($15.50) Ordinary membership £3. 3s. ($ 9.50) Student membership . . . . £2. 2 s. ($ 6.50) There is no admission fee. Student members will be regarded as persons receiving full-time instruction at educational institutions recognized by the Council. Subscrip- tions are due each January, and should be sent to the Treasurer, Professor P. C. Sylvester-Bradley, Department of Geology, The University, Leicester, England. Palaeontology is devoted to the publication of papers (preferably illustrated) on all aspects of palaeontology and stratigraphical palaeontology. Four parts are published each year and are sent free to all members of the Association. Members who join for 1963 will receive Volume 6, Parts 1 to 4. All back numbers are still in print and may be ordered from B. H. Blackwell, Broad Street, Oxford, England, at the prices shown below (post free): Vol. 1 (for 1957-8) in 4 parts at £2 or $6.00 per part. Vol. 2 (for 1959) in 2 parts at £2 or $6.00 per part. Vol. 3 (for 1960) in 4 parts at £2 or $6.00 per part. Vol. 4 (for 1961) in 4 parts at £2 or $6.00 per part. Vol. 5 (for 1962) in 4 parts at £3 or $9.00 per part. A complete set. Volumes 1-5, consists of 18 parts and costs £40 or $120. Manuscripts on all aspects of palaeontology and stratigraphical palaeontology are invited. They should conform in style to those already published in this journal, and should be sent to Mr. N. F. Hughes, Sedgwick Museum, Cambridge, England. A sheet of detailed instructions for authors will be supplied on request. LOWER CARBONIFEROUS MICROFLORAS OF SPITSBERGEN by G. PLAYFORD PART TWO Part I of this paper will be found in Volume 5, Part 3, pages 550 618, with an abstract on page 550; it i ncludes the list of references. Part II continues and concludes the paper; a contents list is placed at the end of this part. Amilatisporites orbiculatus (Waltz) comb. nov. Plate 88, fig. 1 1941 Zonotriletes orbiculatus Waltz in Luber and Waltz, p. 24; pi. 4, fig. 60. 1957 Euryzonotriletes orbiculatus (Waltz) Naumova; Kedo, p. 1168. Diagnosis. The following is the present writer’s translation of the diagnosis given by Waltz (in Luber and Waltz 1941, p. 24): ‘Diameter — 92-5— 1 37-5 p. Colour brownish yellow. Spore body outline circular; surface of body smooth. Border wide, rather thick, with even or slightly fluted outer edge. On surface of border small wrinkles or folds having concentric orientation are sometimes observed. Thickness of exine on spore body and on border approximately equal. Trilete fissures very prominent, smooth, equal, slightly elevated or thickened. Length of rays equal to, or slightly less than, spore body radius. Z. orbiculatus Waltz is characterized by a considerable variation in the ratio between diameter of spore body and width of border. Diameter of spore body 50-70 p. Width of border 15-75 p.' Description of specimens. The Spitsbergen specimens conform closely to the above diagnosis. Exine thickness is 2-5-4 p on spore body. Cingulum of any particular speci- men is of uniform width. Surface of cingulum laevigate to infrapunctate (oil immersion); punctate in corroded specimens, particularly around spore-body margin. Dimensions (12 specimens). Overall equatorial diameter 92-120 p (mean 105 /x); diameter of spore body 49-71 p (mean 61 p); width of cingulum 16-30 p (mean 22 p). Remarks. The species is included in the genus Anulatisporites on the basis of its broad, sculptureless cingulum. Previous records. Anulatisporites orbiculatus (Waltz) comb. nov. has been recorded from Tournaisian-Visean strata of the Kizel district, U.S.S.R. (Luber and Waltz 1941), and from the Visean of White Russia (Kedo 1957, 1958, 1959). Anulatisporites canalicu/atus sp. nov. Plate 88, figs. 2, 3 Diagnosis. Spores radial, trilete; amb smooth, subtriangular with well-rounded apices and convex sides. Laesurae distinct, straight, length approximately 1-5-4 p less than [Palaeontology, Vol. 5, Part 4, 1962, pp. 619-678, pis. 88-95.] 620 PALAEONTOLOGY, VOLUME 5 spore-body radius; accompanied by conspicuous, flat, smooth, slightly elevated lips, which extend 4-7 p on either side of laesurae and often have lobed outer margins. Spore body laevigate. Cingulum distinctively incised on proximal surface by a single, con- tinuous, very narrow furrow situated approximately 2-5— 5-5 p from, and more or less conformable with, smooth spore-body margin. Cingulum otherwise undifferentiated, laevigate (irregularly punctate in corroded specimens), uniformly broad, much darker in colour than spore body. Dimensions (35 specimens). Overall equatorial diameter 54-86 /a (mean 70 p); diameter of spore body 33-50 ju. (mean 41 /x); width of cingulum 11-21 p (mean 15 p). Holotype. Preparation PI 73/2, 53T 100T. L.1125. Locus typicus. Citadellet (sample G1446), Spitsbergen; Lower Carboniferous. Description. Holotype 79 p overall, spore-body diameter 45 p, width of cingulum 17 p; laesurae extending to within 2-5 p of spore-body margin, lips individually about 4-5 p wide; furrow incised in cingulum uniformly about 4 p from spore-body margin, depth about 2 p. In some specimens the margin between the spore body and the cingulum on the distal hemisphere may be rather undulating showing only general conformity to equatorial outline. Comparison. The generally larger Zonotriletes snlcatus Waltz (in Luber and Waltz 1938, p. 18; pi. 2, fig. 20) has numerous, rather discontinuous, concentric furrows in the cingulum, which is definitely thickened at its inner margin. Genus densosporites (Berry) Potonie and Kremp 1954 Type species. D. covensis Berry 1937. Discussion. This genus and the morphographically associated Anulatisporites Loose ex Potonie and Kremp 1954 are presently receiving consideration from a subcommittee of the International Commission for the Microflora of the Palaeozoic; as a result, their redefinition, together with the erection of several other related genera, seems likely. This reappraisal of the densospore group will be based principally upon the sculpture of the cingulum, and it is to be hoped that due regard will be given to the effects of corrosion, both natural and in preparation, which in many cases seems to cause pro- found cingulate alteration (cf. Bharadwaj 1959, p. 70). Pending publication of the Com- mission’s proposals, the Spitsbergen spores concerned are here assigned to either Densosporites or to Anulatisporites as formally emended by Potonie and Kremp (1954). A ffinity. In view of the abundance of representatives of this genus in sediments (parti- cularly coals) of Carboniferous age, it is surprising that only recently has evidence come forward as to its botanical affinity. Chaloner (1958a) reported microspores similar to Densosporites loricatus (Loose) Schopf, Wilson, and Bentall 1944 from a small Upper Carboniferous lycopod cone compression, which he termed Selaginellites canonbiensis sp. nov. Subsequently, Bharadwaj (1959) obtained microspores conformable with Densosporites from the heterosporous lycopod strobilus Porostrobus zeilleri Nathorst 1914 which had been collected from Lower Carboniferous strata at Pyramiden, Spits- bergen. It will be seen that the abundantly occurring sporae dispersae , described below as Densosporites spitsbergensis sp. nov., resemble closely the microspores obtained by G. PLAYFORD: LOWER CARBONIFEROUS MICROFLORAS 621 Bharadwaj (from P. zeilleri). In a postscript to his paper, Bharadwaj recommended the inclusion of Se/agine/Iites canonbiensis Chaloner within Bothrostrobus (Nathorst) Seward. Densosporites bialatus (Waltz) Potonie and Kremp 1956 Plate 88, figs. 4-7 1938 Zonotriletes bialatus Waltz in Luber and Waltz, p. 22; pi. 4, fig. 51. 1941 Zonotriletes bialatus Waltz var. undulatus Waltz in Luber and Waltz, pp. 28-29; pi. 5, fig. 71a, b. 1941 Zonot iletes bialatus Waltz var. costatus Waltz in Luber and Waltz, p. 29; pi. 5, fig. 72. 1952 Hymenozonotriletes aff. bialatus (Waltz) Ishchenko, p. 51; pi. 13, fig. 124. 1956 Densosporites bialatus (Waltz) Potonie and Kremp, p. 1 14. 1956 Hymenozonotriletes bialatus (Waltz) var. undulatus (Waltz) Ishchenko, pp. 63-64; pi. 12, figs. 135-7. 1957 Cingulizonates tuberosus Dybova and Jachowicz, p. 171; pi. 53, figs. 1-4. 1957 Trematozonotriletes bialatus (Waltz) Naumova; Byvsheva, p. 1010. Description of specimens. Spores radial, trilete; amb roundly subtriangular to oval, more or less conformable with convexly subtriangular body outline. Laesurae percep- tible or not visible (corroded specimens); simple, straight to sinuous, length approxi- mately equal to body radius. Where preserved, body exine is finely granulate or punctate. Differentiated cingulum, consisting of: an inner, thickened, opaque portion charac- teristically sculptured with fine, radially elongated pits; surrounded by a thinner, translucent zone which is approximately one-third to half of the total cingulum width. Conspicuous junction between the two parts of the cingulum may be regular, conform- ing closely with the spore-body outline; in many cases, however, it is irregularly lobed or dentate due to radial, equatorially tapering extensions of the thickened part project- ing into, but rarely attaining margin of, the outer thinner portion. Dimensions (60 specimens). Overall equatorial diameter 46-77 /x (mean 60 /x); diameter of spore body 21-34 p. (mean 27 /x). Remarks. In her diagnosis of Zonotriletes bialatus , Waltz (in Luber and Waltz 1938, p. 22) drew attention to the variable structure of the inner thickened portion of the cingulum, suggesting its dependence upon the state of preservation. Subsequently, Waltz (in Luber and Waltz 1941, pp. 28-29) delineated two varieties (undulatus and costatus) within the species, on the basis of this variation. Both varieties are represented in the Spitsbergen assemblages, but their continuous intergradation does not support their recognition as separate morphographical units. The illustrations of Cingulizonates tuberosus Dybova and Jachowicz 1957 (pi. 53, figs, l^f) strongly suggest conspecificity with Densosporites bialatus (Waltz), and indeed Jachowicz (1958, table 8) subsequently equated the two species. There seems little doubt of the presence of D. bialatus within the Upper Mississippian spore assemblage described by Hacquebard and Barss (1957). These authors remarked (p. 32) that their species Densosporites irregularis ‘may be conspecific with Zonotriletes bialatus Waltz, 1938’, and certainly the spores represented by their plate 4, figs. 12, 13 (D. irregularis) and by plate 4, fig. 10 (D. cuneiformis) show close resemblance to D. bialatus. Previous records. Densosporites bialatus (Waltz) has been recorded by numerous Russian 622 PALAEONTOLOGY, VOLUME 5 palynologists from the Lower Carboniferous of the U.S.S.R. (Luber and Waltz 1938, 1941; Ishchenko 1952, 1956, 1958; Byvsheva 1957, 1960; Loginova 1959). It has been recorded also from the Namurian A to Westphalian B interval of the Upper Silesian Coal Measures (Dybova and Jachowicz 1957; Jachowicz 1958), and is probably present in the Upper Mississippian of the South Nahanni River area, Northwest Territories, Canada (Hacquebard and Barss 1957). Ishchenko (1956) documented occurrences of the species, in the western Donetz Basin, from Visean to Namurian, and subsequently (1958), in the Dnieper-Donetz Basin, from Tournaisian to Bashkirian. Densosporites dentatus (Waltz) Potonie and Kremp 1956 Plate 88, figs. 14, 15 1884 Type 274 of Reinsch, p. 27; pi. 20, fig. 128a. 1938 Zonolritetes dentatus Waltz in Luber and Waltz, p. 20; pi. 14, fig. 47. 1956 Densosporites dentatus (Waltz) Potonie and Kremp, p. 115. 1958 Hymenozonotriletes dentatus (Waltz) Ishchenko, pp. 70-71 ; pi. 7, fig. 96. Description of specimens. Spores radial, trilete; amb oval to roundly subtriangular. Laesurae simple, straight to sinuous, extending to spore-body margin. Exine of spore body laevigate to granulate; very thin, hence often poorly preserved or absent. Cingulum uniform, relatively dark in colour, width 9-20 p, equatorial margin regularly dentate. Dimensions (50 specimens). Overall equatorial diameter 36-65 p (mean 49 p); diameter of spore body 20-3 1 p (mean 25 p). EXPLANATION OF PLATE 88 All figures X 500, and from unretouched negatives. Fig. 1. Anulatisporites orbiculatus (Waltz) comb. nov. Proximal surface; preparation P148/4, 48-2 95 0 (L.1124). Figs. 2, 3. Anulatisporites canaliculatus sp. nov. 2, Proximal surface; preparation P163/6, 44-2 1 12-7 (L. 1 126). 3, Flolotype; proximal surface. Figs. 4-7. Densosporites bialatus (Waltz) Potonie and Kremp 1956. 4, Distal surface; preparation P164/5, 38-2 93-1 (L.l 129). 5, Distal surface; preparation P164/9, 35-3 101-4 (L.l 128). 6, Proximal surface; preparation P167B/3, 50-6 95-1 (L.l 130). 7, Distal surface; preparation P167B/1, 28-6 94-3 (L.l 131). Figs. 8, 9. Densosporites subcrenatus (Waltz) Potonie and Kremp 1956. 8, Proximal surface; prepara- tion P145B/32, 41 -5 103-3 (L.l 134). 9, Proximal surface; preparation P145C/1, 29-0 94-9 (L. 1135). Figs. 10. 11, Densosporites diatretus nom. nov. 10, Proximal surface; preparation P176A/1, 40-9 95-4 (L.1137). 11, Distal surface; preparation P148/1, 25-0 95-4 (L.1136). Figs. 12, 13. Densosporites striatiferus Hughes and Playford 1961. 12, Proximal surface; preparation P172/3, 25-9 95-5 (L.l 145). 13, Proximal surface; preparation PI 70/1, 23-8 97-2 (L.l 144). Figs. 14, 15. Densosporites dentatus (Waltz) Potonie and Kremp 1956. 14, Proximal surface; prepara- tion P148/1, 45-2 95-6 (L.l 132). 15, Distal surface; preparation P143B/5, 33-8 106-7 (L.l 133). Figs. 16, 17. Densosporites aculeatus sp. nov. 16, Holotype; distal surface. 17, Proximal surface; preparation P201/2, 29-8 102-1 (L.l 164). Fig. 18. Densosporites sp. Proximal surface; preparation PI 67B/1 3, 38-8 103-0 (L.l 166). Figs. 19-22. Densosporites variabilis (Waltz) Potonie and Kremp 1956. 19, 20, Distal and proximal surfaces respectively; preparation P154/6, 22-7 100-8 (L.l 140). 21, Proximal surface; preparation P145B/31, 36-3 102-7 (L.1138). 22, Proximal surface; preparation P158/4, 21-1 93-5 (L.1139). Palaeontology, Vol. 5 PLATE 88 m &#■ PLAY FORD, Lower Carboniferous microspores G. PLAYFORD: LOWER CARBONIFEROUS MICROFLORAS 623 Comparison. Some of the spores described by Hoffmeister, Staplin, and Malloy (1955, p. 386; pi. 36, figs. 16, 17) as Densosporites spinifer, and subsequently recorded as such by Butterworth and Williams (1958, p. 359; pi. 3, fig. 46) and by Love (1960, p. 109), may be representative of D. dentatus (Waltz). Previous records. Recorded initially by Reinsch (1884) from the Russian Carboniferous. Later and more precisely documented Russian occurrences are from the Lower Carboni- ferous of the Moscow Basin and of the Kizel, Selizharovo, Voronezh, and Borovichi districts (Luber and Waltz 1938, 1941), and from exclusively Visean sediments of the Dnieper-Donetz Basin (Ishchenko 1958). Thus this Spitsbergen occurrence is the first reported definitely outside Russia. Densosporites suberenatus (Waltz) Potonie and Kremp 1956 Plate 88, figs. 8, 9 1938 Zonotriletes suberenatus Waltz in Luber and Waltz, p. 19; pi. 4, fig. 43. 1956 Densosporites suberenatus (Waltz) Potonie and Kremp, p. 116. 1958 Hymenozonotriletes suberenatus (Waltz) Ishchenko, p. 77; pi. 9, fig. 112. [non Tendosporites suberenatus (Waltz) Hacquebard and Barss 1957, p. 36; pi. 5, figs. 3, 4.] Description of specimens. Spores radial, trilete; amb subtriangular, more or less con- formable with spore-body outline. Laesurae distinct, simple, straight, length slightly less than body radius. Spore-body exine essentially laevigate, sometimes finely wrinkled; body outline triangular with rounded apices and ± straight sides. Cingulum laevigate; with crenulate, fringe-like equatorial margin which is often at least partially absent in poorly preserved specimens. Corroded specimens often tend to approach the aspect of Tripartites, notably of T. incisotrilobus (Naumova; Waltz) Potonie and Kremp 1956 (cf. Waltz in Luber and Waltz 1938, p. 19; Ishchenko 1958, p. 77), although incisement or embayment of the cingulum is not necessarily located interradially. Dimensions (30 specimens). Overall equatorial diameter 44-65 /x (mean 55 /x) ; diameter of spore body 26-39 /x (mean 32 f). Comparison. The specimens described by Hacquebard and Barss (1957, p. 36; pi. 5, figs. 3, 4) as Tendosporites suberenatus (Waltz) were incorrectly referred to Waltz’s species, since they possess a cingulum which is ‘irregularly thickened at the periphery’; this is not a feature diagnosed by Waltz or evident from the Spitsbergen representatives. Some of the spores figured by Reinsch ( 1 884, e.g. pi. 3, figs. 38, 41 ; pi. 1 7, fig. 41 ; pi. 19, fig. 41d; pi. 20, fig. 118l) resemble Densosporites suberenatus (Waltz). Previous records. Previous definite occurrences are confined to the Russian Lower Carboniferous. Luber and Waltz (1938, 1941 ) record the species from the Moscow Basin and Kizel region, and Ishchenko (1958, stratigraphical range table 3) found it to be restricted to Visean-Namurian strata of the Dnieper-Donetz Basin. Densosporites diatretus nom. nov. Plate 88, figs. 10, 11 ; text-fig. 9 a 1941 Zonotriletes intermedins Waltz in Luber and Waltz, pp. 27-28; pi. 5, fig. 68. 1956 Hymenozonotriletes intermedins (Waltz) Ishchenko, pp. 64-65; pi. 12, fig. 139. [non Densosporites intermedins Butterworth and Williams, 1958, p. 379; pi. 3, figs. 38, 39.] 624 PALAEONTOLOGY, VOLUME 5 Diagnosis. The following is the present writer’s translation of the diagnosis given by Waltz {in Luber and Waltz 1941): ‘Diameter — 55—70 yu,. Colour brownish yellow. Out- line of spore body roundly triangular. Border wide, thick, bearing superficially two types of sculpture. Nearer to the inside edge of the border is an arrangement of short, radial grooves ; on the rest of the surface sparsely distributed tuberculate thickenings can be observed. The former type of sculpture comes close to that of Zonotriletes variabilis Waltz var. valleculosus Waltz, the second shows much similarity to the sculpture of Zonotriletes polyzonalis Waltz. The fact that the species described is found in con- junction with the two others mentioned, and also the similarity of morphological features, argues in favour of the existence of a definite link between them. Diameter of spore body 15-25 /x. Width of border 15-30 /x.’ Holotype (here designated). Spore illustrated by Luber and Waltz 1941, pi. 5, fig. 68 (here reproduced as Text-fig. 9a). text-fig. 9. a, Densosporites diatretus nom. nov., redrawn from Luber and Waltz 1941, pi. 5, fig. 68. b, Lophozonotriletes rarituberculatus (Luber) Kedo 1957, redrawn from Luber and Waltz 1941, pi. 5, fig. 76. c. X 500. Description of specimens. Those observed in the Spitsbergen assemblages conform closely to the above diagnosis, and to the following additional remarks. Amb varies from convexly subtriangular to triangular (this variation was noted also by Ishchenko 1956, 1958). The radial grooves are confined to the inner margin of the proximal surface of the cingulum, and are often much finer and more closely spaced than in the spore illustrated by Waltz {in Luber and Waltz 1941 ; pi. 5, fig. 68) and repro- duced herein (text-fig. 9a). The positive sculptural elements on the remainder of the cingulum are usually more strongly developed on the distal surface; in different speci- mens they range from small coni to larger rod-like thickenings. The cingulum is often rather indistinctly differentiated into an outer light zone and an inner, darker (thicker) zone; this feature was emphasized by Ishchenko (1958, p. 71). Laesurae, apparent only on well-preserved specimens, are distinct, simple, straight to slightly sinuous, length approximately equal to spore-body radius, sometimes extending on to cingulum. Dimensions (70 specimens). Overall equatorial diameter 55-76 /x (mean 66 p); diameter of spore body 16-35 /x (mean 25 /x); width of cingulum 14-25 /x (mean 20 p). Remarks. This species is included within Densosporites (Berry) Potonie and Kremp on the basis of its massive, distinctively sculptured cingulum. Ishchenko (1956, 1958) transferred Zonotriletes intermedins Waltz 1941 to Hymenozonotriletes Naumova 1937; however, the latter genus as understood by Potonie (1958, p. 29) and evidently by G. PLAYFORD: LOWER CARBONIFEROUS MICROFLORAS 625 Naumova (1953) embraces prominently zonate forms having conspicuous spinose sculpture. Thus Ishchenko’s assignment of this species is unacceptable. Comparison. Densosporites diatretus nom. nov. shows some resemblance to Vallatisporites Hacquebard (1957, p. 312) but lacks the distinct ‘groove or rampart-like area’ charac- teristic of that genus. Butterworth and Williams (1958, p. 379) described, from the Scottish Lower Carboniferous, a species which they named Densosporites intermedins. These spores are clearly different from those of Hymenozonotriletes intermedins (Waltz 1941); hence it is necessary to erect a new trivial epithet for the species on its inclusion in Densosporites (ref. articles 55 and 64 of the 1961 International Code of Botanical nomenclature). Previous records. Densosporites diatretus nom. nov. has been recorded previously from Russia only, as follows: Lower Carboniferous of the Moscow Basin and Kizel region (Luber and Waltz 1941); Tournaisian to Middle Visean only of the western extension of the Donetz Basin (Ishchenko 1956); and Tournaisian, Visean, and Namurian of the Dnieper-Donetz Basin (Ishchenko 1958). Densosporites variabilis (Waltz) Potonie and Kremp 1956 Plate 88, figs. 19-22 1938 Zonotriletes variabilis Waltz in Luber and Waltz, pp. 20-21 ; pi. 4, figs. 44-46, and pi. A, fig. 16. 1941 Zonotriletes variabilis Waltz var. foveolatus Waltz in Luber and Waltz, p. 26; pi. 5, fig. 66 a. 1941 Zonotriletes variabilis Waltz var. fossulatus Waltz in Luber and Waltz, p. 26; pi. 5, fig. 66 b. 1941 Zonotriletes variabilis Waltz var. valleculosus Waltz in Luber and Waltz, p. 27; pi. 5, fig. 66c. 1956 Densosporites variabilis (Waltz) Potonie and Kremp, p. 116. 1956 Trematozonotriletes variabilis (Waltz) Ishchenko var. foveolatus Waltz; Ishchenko, pp. 102-3; pi. 22, fig. 248. 1957 Trematozonotriletes variabilis (Waltz) Naumova; Byvsheva, p. 1010. [non Densosporites variabilis (Waltz) Potonie and Kremp; Butterworth and Williams 1958, pp. 380-1 ; pi. 3, figs. 32-34.] Description of specimens. Spores radial, trilete; amb roundly subtriangular. Laesurae straight to sinuous, elevated and slightly thickened; frequently not preserved due to delicate spore-body exine. Uniformly thick cingulum prominently sculptured on proximal surface with numerous shallow pits or grooves arranged radially around outer margin of spore body; cavities rarely extend radially beyond centre of cingulum. Addi- tional, irregular pitting on cingulum is often present, and may be attributable to cor- rosion. Spore body laevigate to granulate; outline more or less conformable with amb. Equatorial margin smooth, undulating, dentate or lobate. Dimensions (80 specimens). Overall equatorial diameter 41-77 p (mean 60 p); diameter of spore body 19-34 p (mean 26 p). Remarks. Three of the four illustrations of Zonotriletes variabilis in Luber and Waltz 1938 (pi. 4, figs. 44-46) were reproduced in Luber and Waltz 1941 (pi. 5, fig. 66a-c) and designated infraspecifically as the following varieties: foveolatus, fossidatns, and va/lecn- losns , respectively .However, continuous morphographical variation between these forms 626 PALAEONTOLOGY, VOLUME 5 was noted by Waltz and is confirmed abundantly in the present investigation; as such, their infraspecific recognition does not appear warranted. Comparison. Densosporites diatretus resembles D. variabilis (Waltz) in possessing similarly disposed radial grooves in the cingulum, which, however, is sculptured additionally with conspicuous tuberculate thickenings. As noted by Waltz (in Luber and Waltz 1941), D. diatretus represents a sculptural intermediate between D. variabilis and D . polyzonalis (Waltz) Potonie and Kremp 1956. In the Spitsbergen assemblages the former two species are commonly although not invariably associated, and are certainly at least morpho- graphically closely related. However, specimens positively identifiable with D. polyzonalis have not been observed by the writer. Although showing similar sculpture to the specimens described above, Tremato- zonotriletes variabilis (Waltz) var. trigonalis Ishchenko 1956 (p. 103; pi. 20, fig. 249) possesses a cingulum which is consistently wider about the spore apices, and as such probably represents a distinct species. Butterworth and Williams (1958) incorrectly assigned to Densosporites variabilis (Waltz) a species which they described as being ‘abundant throughout’ their Scottish Namurian assemblages; these authors implied identity of their specimens with that illustrated by Luber and Waltz 1938 (pi. 4, fig. 46, subsequently Zonotriletes variabilis Waltz var. valleculosus Waltz 1941). However, from the description and photographs given by Butterworth and Williams (1958, pp. 380-1; pi. 3, figs. 32-34) and from the study of a slide kindly loaned to the writer by Dr. Butterworth, it is clear that the Scottish specimens differ from D. variabilis in the following important respects: (1) the spore body is rather poorly defined; (2) the cingulum shows relatively abrupt equatorial reduction in thickness; (3) the cingulate sculpture consists of irregular, elevated, radial thickenings enclosing equally irregular, and not invariably radially disposed, lumina, which are often imperfectly defined and are not concentrated along the inner margin of the cingulum. In contrast, D. variabilis possesses closely spaced, well-defined, pyriform pits, which are radially arranged about the distinct spore body, sharply punctuating an otherwise featureless cingulum of fairly uniform thickness; there is no appearance of the ‘radial struts’ described by Butterworth and Williams. Previous records. Densosporites variabilis has been reported by numerous authors (Luber and Waltz 1938, 1941; Ishchenko 1956, 1958; Bludorov and Tuzova 1956; Byvsheva 1957; Kedo 1957, 1958, 1959; Loginova 1959) as an important constituent of Tournaisian, and particularly Visean-Namurian strata in the U.S.S.R. Recently Love (1960) recorded the species from the Pumpherston Shell Bed (Visean) of Scotland, and Hughes and Playford (1961) reported its predominance in one sample (S59a) of the Spitsbergen Lower Carboniferous. Densosporites duplicatus (Naumova) Potonie and Kremp 1956 Plate 89, figs. 6-8 1884 Type 336 of Reinsch, p. 33; pi. 16, fig. 125a. 1884 Type 337 of Reinsch, p. 33; pi. 9, fig. 125. 1938 Zonotriletes duplicatus (Naumova) Waltz in Luber and Waltz, p. 21 ; pi. 4, fig. 53. 1956 Densosporites duplicatus (Naumova) Potonie and Kremp, p. 115. 1957 Labiadensites cf. Z. duplicatus (Naumova; Waltz) Hacquebard and Barss, p. 27 ; pi. 6, fig. 1 . G. PLAYFORD: LOWER CARBONIFEROUS MICROFLORAS 627 Description of specimens. Spores radial, trilete; amb roundly subtriangular to sub- circular. Laesurae distinct, straight, length equal to, or slightly less than, spore-body radius; usually accompanied by minor lip development — lips individually about 3 p broad, with somewhat irregular outer margins. Spore body concavely or convexly sub- triangular to subcircular; laevigate to finely granulate. Outer margin of cingulum strongly and characteristically differentiated into numerous laterally projecting processes which are approximately 10-15 p long, 3-4 p in basal diameter, and are conspicuously expanded and thickened apically into crescentic (mushroom-shaped) caps. These promi- nent peltate processes are usually very closely packed, often appearing to lie in more than one horizontal plane. Cingulum otherwise laevigate, colour slightly darker than body. Dimensions (70 specimens). Overall equatorial diameter (including processes) 51-77 p (mean 64 p); diameter of spore body 26-39 p (mean 32 p). Remarks. On the basis of a single specimen, Hacquebard and Barss (1957) proposed the assignment of Zonotriletes duplicatus (Naumova) to their new genus Labiadensites, which was said to differ from Densosporites in its invariable possession of ‘a strong trilete and greatly developed lips’. It is evident from the examination of numerous Spitsbergen representatives that lips are only sporadically and never strongly developed in this species; furthermore, the earlier descriptions and illustrations given by Reinsch (1884) and Luber and Waltz (1938) contain no reference to such laesurate modification. Hence the species seems more suitably included within Densosporites , as advocated by Potonie and Kremp (1956, p. 115). Previous records. Densosporites duplicatus was first recorded by Reinsch (1884) from Russian ‘Stigmarienkohle’ of presumably Lower Carboniferous age. More recently, the species has been reported from Lower Carboniferous deposits of the Moscow Basin and Kizeland Selizharovo regions, U.S.S.R. (Luber and Waltz 1938, 1941); and from Upper Mississippian coal of the South Nahanni River area, Northwest Territories, Canada (Hacquebard and Barss 1957). Densosporites strict iferus Hughes and Playford 1961 Plate 88, figs. 12, 13 Dimensions (40 specimens). Overall equatorial diameter 44-65 p (mean 54 p); diameter of spore body 27-45 p (mean 35 p)\ width of cingulum 6-12 p (mean 9 p). Densosporites spitsbergensis sp. nov. Plate 89, figs. 1-5 Diagnosis. Spores radial, trilete; amb subtriangular, more or less conformable with body outline. Laesurae perceptible to distinct, straight or slightly sinuous; extending on to cingulum as thickened, elevated ridges which often attain equatorial margin. Spore body convexly subtriangular, exine often poorly preserved or absent. Cingulum robust, darker in colour than body; slight and gradual equatorial decrease in thickness. Pro- minent spinose sculpture on distal surface of spores (body and cingulum); spines 628 PALAEONTOLOGY, VOLUME 5 crowded and frequently coalescent around inner margin of cingulum, reduced in size and density in equatorial region; length of spines 1-5-5 /r, basal diameter 1-2-5 ju. Proximal surface of spores laevigate to sparsely granulate or spinose. Dimensions (100 specimens). Overall equatorial diameter 55-80 \ a (mean 66 p); diameter of spore body 23-39 p (mean 31 p). Holotype. Preparation PI 63/3, 22-2 96-8. L.1146. Locus typicus. Birger Johnsonfjellet (sample G1089), Spitsbergen; Lower Carboniferous. Description. Holotype convexly subtriangular, 64 p overall; spore-body diameter 28 p; laesurae distinct, extending to equatorial margin. The species is characterized by its conspicuous distal spinose sculpture, long laesurae, and well-developed cingulum which shows slight reduction in thickness towards the equator; it is a common microfloral con- stituent of many of the Spitsbergen samples. Comparison. Densosporites pannosus Knox 1950 (p. 326; pi. 18, fig. 267) is more uni- formly and comprehensively spinose and has more prominent, laesurate lips. Remarks. The sporae dispersae described above as Densosporites spitsbergensis sp. nov. compare closely in all respects with the microspores obtained by Bharadwaj (1959, p. 70; pi. 2, figs. 8-14) from the fructification Porostrobus zeilleri Nathorst 1914, which had been collected in 1882 by Nathorst from the Culm (Lower Carboniferous) at Pyramiden, Spitsbergen. Furthermore, representatives occurring in poorly preserved or overmacerated preparations are very similar to the microspores (from P. zeilleri) which Bharadwaj had treated with excessive potassium hydroxide. From the widespread occurrence of D. spitsbergensis it seems reasonable to assume concomitant widespread distribution of P. zeilleri in Spitsbergen during Lower Carboniferous times. EXPLANATION OF PLATE 89 All figures X 500, and from unretouched negatives. Figs. 1-5. Densosporites spitsbergensis sp. nov. 1, Holotype; proximal surface. 2, Distal surface; preparation P162/5, 50-7 104-9 (L.1147). 3, Proximal surface; preparation PI 63/ 1 , 27 0 96-5 (L.1148). 4, Distal surface; preparation P148/4, 44-2 107-3 (L. 1 149). 5, Proximal surface; prepara- tion PI 64/2, 42-3 103-2 (L.l 150). Figs. 6-8. Densosporites duplicatus (Naumova) Potonie and Kremp 1956. 6, Proximal surface; pre- paration P145A/1, 45 0 110-0 (L.l 141). 7, Proximal surface; preparation P145B/1, 23-1 104-7 (L.l 142). 8, Proximal surface; preparation P145B/27, 26-3 103-2 (L.l 143). Figs. 9-13. Densosporites variomarginatus sp. nov. 9, Proximal surface; preparation P148/56, 39-2 103-7 (L.l 153). 10, Proximal surface; preparation P162/6, 30-0 106-4 (L.l 154). 11, Holotype; proximal surface. 12, Proximal surface; preparation P148/27, 35-3 104-5 (L.l 156). 13, Proximal surface; preparation P163/6, 38-9 101-2 (L.l 155). Figs. 14, 15. Knoxisporites cinctus (Waltz) Butterworth and Williams 1958. Proximal and distal surfaces respectively; preparation P163/7, 30-4 98-9 (L.l 170). Figs. 16, 17. Lycospora uber (Hoffmeister, Staplin, and Malloy) Staplin 1960. 16, Distal surface; pre- paration P180B/1, 52-8 105-0 (L.l 180). 17, Proximal surface; preparation P180B/4, 43-7 106-4 (L.l 181). Figs. 18-21. Densosporites rarispinosus sp. nov. 18, Proximal surface; preparation P180B/1, 51-5 101-5 (L.1159). 19, Distal surface; preparation P145C/2, 34-7 107-3 (L.1160). 20, Holotype; proximal surface. 21, Distal surface; preparation P145B/1, 1 7-9 96-7 (L.l 161). Palaeontology , Vol. 5 PLATE 89 PLAYFORD, Lower Carboniferous microspores G. PLAYFORD: LOWER CARBONIFEROUS MICROFLORAS 629 Densosporites variomarginatus sp. nov. Plate 89, figs. 9-13 Diagnosis. Spores radial, trilete, subtriangular. Equatorial margin irregular, i.e. smooth, undulating, dentate or lobate. Laesurae distinct, simple, usually straight, almost attain- ing spore-body margin. Body laevigate, sometimes finely wrinkled; outline subtriangular with rounded apices and convex to slightly concave sides. Cingulum relatively dense, laevigate or with punctations arranged parallel to spore-body outline. Cingulum has perceptibly to distinctly radiating or striated appearance due apparently to an alterna- tion of intrinsic, non-elevated, usually poorly defined radial ‘bands’ of differing thick- ness; the breadth of these bands is (collectively) highly variable. Dimensions (100 specimens). Overall equatorial diameter 44-102 p (mean 68 /x); diameter of spore body 27-55 p (mean 39 /a); (maximum) width of cingulum 7-27 /a (mean 15 /a). Holotype. Preparation P148/62, 40-8 104-9. L.1152. Locus typicus. Triungen (sample G1472), Spitsbergen; Lower Carboniferous. Description. Holotype 77 p overall; spore body microrugulate, outline convexly sub- triangular, diameter 43 p; cingulum concentrically and finely punctate, width fairly uniform (c. 17 p ), overall distinctly radiating appearance; equatorial margin irregularly undulating. Despite its generally ill-defined nature (particularly in well-preserved specimens), the radially striated structure of the cingulum is always recognizable. Corrosion, either natural or in preparation, appears to have the effect of emphasizing the structure by embaying the thinner, radial areas, and resulting in an undulating or distinctly lobed equatorial margin. Thus the highly variable nature of the periphery of the cingulum, ranging as a continuous variation from entire to deeply and irregularly incised, is con- sidered to be the result of a concomitant variation in preservation from excellent to poor, respectively. That the margin of the cingulum is highly susceptible to corrosive attack is indicated by the comparative scarcity, even in generally well-preserved assemblages, of specimens possessing an entire, uniformly broad cingulum, and further by the invariable absence of such specimens in poorly preserved assemblages. In some specimens the cingulum appears thickest about the triangular apices of the body. Comparison. Densosporites striatus (Knox 1950, p. 330; pi. 19, fig. 289) Butterworth and Williams 1958 differs from D. variomarginatus sp. nov. in having a cingulum that is differentiated into an inner thickened portion and an outer, distinctly thinner zone. The cingulum of D. subcrenatus (Waltz) Potonie and Kremp 1956 is marginally crenulate and of essentially uniform, certainly non-striated appearance. Tendosporites subcrenatus ( non Waltz) Hacquebard and Barss 1957 (p. 36; pi. 5, figs. 3, 4) has shorter laesurae than D. variomarginatus and is further distinguished by the irregular peripheral thickening of its cingulum, which is otherwise of approximately the same density as the spore body. D. heterotomus (Waltz in Luber and Waltz 1938, pp. 19-20; pi. 2, fig. 28) Potonie and Kremp 1956 may be similar to D. variomarginatus. The drawing given by Luber and Waltz depicts a striate cingulum, which is not, however, described as such in the text or evident from type 612 of Reinsch (1884, p. 60; pi. 38, fig. 257) with which Waltz equated her species. Moreover, and in contrast with D. variomarginatus , D. heterotomus possesses 630 PALAEONTOLOGY, VOLUME 5 thickened laesurate lips, is often granulate, and generally much larger (95-120 p). D. striatiferus Hughes and Playford 1961 has much finer and more closely spaced cingulate striations than D. variomarginatus. Densosporites rarispinosus sp. nov. Plate 89, figs. 18-21 ; text-fig. 10 d Diagnosis. Spores radial, trilete; amb more or less conformable with convexly sub- triangular spore-body outline. Laesurae simple, perceptible to distinct, straight or sinuous, extending equatorially 2-4 p beyond body margin. Conspicuous distal sculp- ture of sparsely and irregularly distributed simple spines, which usually project also from equatorial margin; spinae variable in height (1-6 p), bases circular or subcircular (diameter 0-5-3 p); subordinate, small verrucae occasionally additionally present. Apart from this sculpture, spore body and cingulum laevigate to finely punctate (corroded specimens). Cingulum non-tapering, and much darker in colour than spore body. Dimensions (60 specimens). Overall equatorial diameter 37-67 p (mean 51 p)\ diameter of spore body 18-33 p (mean 24 p). Holotype. Preparation P145C/1, 49-6 98-1. L.1158. Locus typicus. Triungen (sample G1466), Spitsbergen; Lower Carboniferous. Description. Holotype 53 p overall, spore body 27 p; irregularly disposed distal spinae 1-5-6 p long, 1-2-5 p broad at base, 4-12 p apart, progressively sparser towards equator; cingulum and body otherwise infrapunctate; sinuous laesurae extending on to cingulum, 2 p beyond body margin. This distinctive species is characterized by sparse, but con- spicuous, spinose distal sculpture, together with consistent slight extension of the laesurae into the cingulum. Remarks. Smith (1960) has demonstrated the existence of two distinct wall layers in several species of Densosporites and Anulatisporites — namely an inner membrane (intexine) forming the ‘central body’ and an outer layer (exoexine) which is equatorially expanded and thickened, thus constituting the cingulum. A similar wall construction is evident in Densosporites rarispinosus sp. nov.; probably overmacerated specimens (e.g. PI. 89, fig. 19) show a more or less distinct separation of the two wall layers. The same effect has been discussed and illustrated by Bharadwaj (1959, p. 70; pi. 2, figs. 13, 14) in the case of excessively macerated, Densosporites-type microspores of the fructification Porostrobus zeilleri Nathorst. Comparison. Densosporites spinifer Hoffmeister, Staplin, and Malloy 19556 (pp. 386-7; pi. 36, figs. 16, 17) differs from D. rarispinosus in possessing a coarsely granulate, rela- tively larger, non-spinose spore body; the spinae of D. spinifer are often closely packed and apparently developed on both proximal and distal surfaces of the cingulum. D. brevispinosus Hoffmeister, Staplin, and Malloy 19556 (p. 386; pi. 36, fig. 22) is sub- circular and has a variably differentiated, minutely spinose cingulum enclosing a granu- late spore body. The spinose sculpture of D. spinosus Dybova and Jachowicz 1957 (pp. 164-5; pi. 49, figs. 1-4) is more strongly developed than in D. rarispinosus, the cingulum thickness decreases equatorially and the proximal surface is granulate. D. G. PLAYFORD: LOWER CARBONIFEROUS MICROFLORAS 631 dentatus (Waltz) Potonie and Kremp 1956 has a regularly dentate equatorial margin, but is laevigate or granulate on the proximal and distal surfaces. Densosporites aculeatus sp. nov. Plate 88, figs. 16, 17; text-fig. lOe Diagnosis. Spores radial, trilete; amb conformable with convexly subtriangular outline of spore body. Laesurae indistinct, simple, straight to curved or sinuous, extending to, or just beyond, body margin; frequently not preserved owing to fragility of proximal body wall. Width and thickness of cingulum fairly uniform, colour much darker than spore body. Equatorial margin and whole of distal surface bear numerous, stout, con- spicuously tapering, simple spinae, which have ± circular bases and are variably spaced (but rarely coalescent); length of spines 2-5-9 p (usually about 5 p), basal diameter 1-5-5 p (average 3-5 p). Apart from spinose sculpture — spore body laevigate to infra- granulate, cingulum laevigate (irregularly punctate in corroded specimens). Dimensions (36 specimens). Overall equatorial diameter (excluding spinose projections) 3 1—57 /x (mean 43 p); diameter of spore body 18-32 p (mean 26 p). Holotype. Preparation PI 64/3, 22-3 96-9. L.1163. Locus typicus. Birger Johnsonfjellet (sample G1095), Spitsbergen; Lower Carboniferous. Description. Holotype roundly subtriangular, 40 p overall; prominently spinose distally and (particularly) equatorially; spinae 4-7 p long, 3-4 p broad at base; cingulum other- wise laevigate, spore body finely granulate; body diameter 28 p. Comparison. Densosporites aculeatus sp. nov. resembles D. spinifer Hoffmeister, Staplin, and Malloy 19556 (pp. 386-7; pi. 36, figs. 16, 17), but differs in bearing spines on the distal surface of the spore body. SpinozonotriJetes' ? exiguus Staplin 1960 (p. 22; pi. 4, figs. 26-28) is circular and has comparatively short laesurae, but otherwise seems very similar to D. aculeatus. Another closely allied species is D. rarispinosus sp. nov. ; this is distinguishable, however, in its much less strongly developed spinose sculpture, and always clearly discernible laesurae. Densosporites sp. Plate 88, fig. 18 Description of specimens. Spores radial, trilete; amb roundly subtriangular. Laesurae distinct, simple, straight, extending to spore-body margin. Body subtriangular with straight to slightly convex sides and rounded to somewhat pointed apices; laevigate or faintly punctate, irregularly thickened on distal surface. Broad cingulum of fairly uniform width and similar density to spore body; sculpture irregularly and minutely scabrate to areolate, particularly in equatorial region. Dimensions (2 specimens). Overall equatorial diameter 77-92 p; diameter of spore body 37-40 p. Comparison. The only comparable species to have appeared in the literature is Zono- triletes latizonalis Waltz (in Luber and Waltz 1941, p. 32; pi. 6, fig. 92); this differs from the specimens described above in its marginally serrate cingulum and smaller spore body (diameter 20-25 p). 632 PALAEONTOLOGY, VOLUME 5 Genus labiadensites Hacquebard and Barss 1957 Type species. L. attenuatus Hacquebard and Barss 1957. Affinity. Unknown. Labiadensites fimbriatus (Waltz) Hacquebard and Barss 1957 Plate 90, figs. 1-3 1938 Zonotriletes fimbriatus Waltz in Luber and Waltz, p. 20; pi. 2, fig. 25. 1956 Hymenozonotriletes fimbriatus (Waltz) Ishchenko, p. 63; pi. 12, fig. 133. 1956 Densosporites fimbriatus (Waltz) Potonie and Kremp, p. 115. 1957 Labiadensites fimbriatus (Waltz) Hacquebard and Barss, p. 28; pi. 4, fig. 2. Description of specimens. Spores radial, trilete; amb circular to subcircular. Laesurae distinct, straight, almost attaining spore-body margin; flanked by broad, flat lips extend- ing 6-10 p on either side of laesurae and having undulating outer margins. Spore body laevigate to infrapunctate. Cingulum smooth, dense ; encompassed by a more translucent, less robust equatorial border, which has a frilled, rather membranous appearance; boundary between these is usually well defined and conformable with the smooth, circular spore-body margin. Some specimens were observed in which the membranous border overlaps rather irregularly on to the inner part of the cingulum, particularly on its distal surface. Also, the outer portion sometimes shows considerable variation in width on any one specimen (see PI. 90, fig. 1), in which case the equatorial outline is broadly undulating. Dimensions (7 5 specimens). Overall equatorial diameter 90-144 p (mean 1 15 p); diameter of spore body 50-88 p (mean 69 p). Comparison. Zonotriletes ciliato-marginatus Waltz (in Luber and Waltz 1941, pp. 21- 22; pi. 4, fig. 52) has similar, but less concise, differentiation of the cingulum, the outer portion of which is thickly covered with small projections. Some specimens of L. fimbriatus (e.g. PI. 90, fig. 3), in which the outer membranous border has been partially removed, appear as transitional forms linking this species with Anulatisporites labiatus Hughes and Playford 1961, which has a smooth undifferentiated cingulum. Thus the two species may well be closely related. EXPLANATION OF PLATE 90 All figures X 500, and from unretouched negatives. Figs. 1-3. Labiadensites fimbriatus (Waltz) Hacquebard and Barss 1957. 1, Distal surface; preparation P148/41, 340 106-6 (L.1167). 2, Proximal surface; preparation P148/5, 52-4 108-9 (L.1168). 3, Proximal surface; preparation PI 63/7, 27-1 111-3 (L.1169). Figs. 4-6. Knoxisporites margarethae Hughes and Playford 1961. 4, Distal surface; preparation P173/1, 20-2 112-5 (L. 1171). 5, 6, Distal and proximal surfaces respectively; preparation M811/1, 42-5 110-4 (L.1172). Figs. 7, 8. Knoxisporites literatus (Waltz) comb. nov. 7, Proximal surface; preparation PI 63/7, 47-7 107-2 (L. 1 173). 8, Proximal surface; preparation P163/7, 31-4 102-8 (L.1174). Figs. 9-12. Knoxisporites hederatus (Ishchenko) comb. nov. 9, Proximal surface; preparation PI 8 1/5, 35-3 95-8 (L.1178). 10, Proximal surface; preparation P148/5, 47-7 112-8 (L. 1 175). 11, Proximal surface; preparation P148/5, 24-4 100-9 (L.1177). 12, Proximal surface; preparation P148/55, 37-8 105-4 (L.1176). Palaeontology, Vol. 5 PLATE 90 PLAYFORD, Lower Carboniferous microspores G. PLAYFORD: LOWER CARBONIFEROUS MICROFLORAS 633 Previous records. This distinctive species was apparently widespread in the Northern Hemisphere during Lower Carboniferous times, with previous records from the Tour- naisian-Visean of the Moscow Basin and Kizel region (Luber and Waltz 1938, 1941); from the Tournaisian of the western Donetz Basin (Ishchenko 1956); from the Visean of the Dnieper-Donetz Basin (Ishchenko 1958); and from Upper Mississippian coal of the South Nahanni River area, Northwest Territories, Canada (Hacquebard and Barss 1957). Genus knoxisporites (Potonie and Kremp) Neves 1961 Type species. K. hageni Potonie and Kremp 1954. Discussion. Neves (1961) has emended the diagnosis of Knoxisporites Potonie and Kremp 1954, and thereby transferred the genus from the Murornati to the Cingulati. Certainly many of the species (including the type) assigned to Knoxisporites appear to be definitely cingulate, in addition to their possession of prominent muri variously arranged on the distal hemisphere. In many instances, however, the distinction between cingulum and equatorially disposed mura would not seem as clear as is implied by Neves (1961). Knoxisporites may be considered analogous to Lophozonotriletes (Naumova) Potonie 1958, differing mainly in sculptural characteristics. Affinity. Unknown. Knoxisporites cinctus (Waltz) Butterworth and Williams 1958 Plate 89, figs. 14, 15 1938 Zonotriletes cinctus Waltz in Luber and Waltz, p. 22 (no description); pi. 2, fig. 27. 1956 Anulatisporites cinctus (Waltz) Potonie and Kremp, p. ill. 1958 Eury zonotriletes cinctus (Waltz) Ishchenko, table 3. 1958 Knoxisporites cinctus (Waltz) Butterworth and Williams, p. 370; pi. 2, figs. 11-13. Dimensions (45 specimens). Overall equatorial diameter 58-94 p (mean 75 p); diameter of spore body 38-69 p (mean 54 p). Previous records. Knoxisporites cinctus (Waltz) has been reported previously (a) from Russia by Luber and Waltz (1938, 1941) from the Lower Carboniferous of the Voronezh and Selizharovo districts, and by Ishchenko (1958) from Namurian rocks of the Dnieper- Donetz Basin; ( b ) from Scotland by Butterworth and Williams (1958) from the upper part of the Limestone Coal Group (Namurian A); (c) from one sample (B685) of the Lower Carboniferous of Spitsbergen (Hughes and Playford 1961). Knoxisporites margarethcie Hughes and Playford 1961 Plate 90, figs. 4-6 Remarks. Study of numerous additional specimens has indicated that the species is definitely cingulate, with the distal thickened ring developed at or near the cingulum/ spore-body margin; and further that the distal extra-reticulum appears to be supported by, although distinct from, the smooth distal muri. Dimensions (70 specimens). Overall equatorial diameter 64-1 1 7 p (mean 90 p) ; diameter of spore body 37-74 p (mean 53 p). 634 PALAEONTOLOGY, VOLUME 5 Knoxisporites literatus (Waltz) comb. nov. Plate 90, figs. 7, 8 1938 Zonotriletes literatus Waltz in Luber and Waltz, p. 18; pi. 2, fig. 21, and pi. A, fig. 11. 1956 Euryzonotriletes literatus (Waltz) Ishchenko, pp. 52-53; pi. 9, fig. 108. 1956 Anulatisporites literatus (Waltz) Potonie and Kremp, p. 111. 1957 Cineturasporites literatus (Waltz) Hacquebard and Barss, pp. 23-24; pi. 3, figs. 2-5. Description of specimens. Spores radial, trilete; amb convexly subtriangular, smooth or may show gentle undulation. Laesurae distinct, straight, length equal to, or slightly less than, spore-body radius; bordered by broad, smooth, flat lips which extend approxi- mately 6-10 p on either side of laesurae. Cingulum broad, usually regular, width 8- 19 p; inner margin sometimes darker in colour, possibly indicating poleward extension (3-5 p) over spore body. In some specimens the cingulum is slightly narrower at the apices, so that the amb tends to appear more roundly triangular than the equatorial out- line of the spore body. Distal surface has characteristic sculpture of several (usually three or four) smooth, rounded muri, which are rather irregularly disposed and often loosely connected; width of muri 6-5-12 p. Apart from lips and distal muri, spore body and cingulum laevigate. Dimensions (75 specimens). Overall equatorial diameter 56-102 p (mean 76 p); diameter of spore body 42-74 p (mean 56 p). This corresponds closely to the combination of the dimensions reported for the species by Waltz (in Luber and Waltz 1938), Ishchenko (1956, 1958) and Hacquebard and Barss (1957). Remarks. This cingulate species, possessing well-developed distal muri, is conformable with Knoxisporites Potonie and Kremp as emended by Neves (1961). The ‘overlap’ of the cingulum on to the spore body is infrequently apparent and it was not mentioned in the original specific diagnosis (Waltz in Luber and Waltz 1938, p. 18); thus assign- ment to Cineturasporites Hacquebard and Barss 1957 is unacceptable. Previous records. This characteristically Lower Carboniferous species has been reported previously from the U.S.S.R. (Luber and Waltz 1938, 1941; Ishchenko 1956, 1958), Canada (Hacquebard and Barss 1957), and Spitsbergen (Hughes and Playford 1961). Probable representatives occur also in the Upper Devonian of Western Australia (Balme and Hassell 1962, p. 11). On the basis of vertical distribution studies in the Dnieper- Donetz Basin, Ishchenko (1958, stratigraphical range table 3) indicates a range from Upper Devonian to Namurian. Knoxisporites hederatus (Ishchenko) comb. nov. Plate 90, figs. 9-12; text-fig. 10a 1956 Euryzonotriletes hederatus Ishchenko, pp. 58-59; pi. 10, fig. 121. Description of specimens. Spores radial, trilete; amb circular to subcircular. Distinct spore body encompassed by more or less conformable cingulum (width 6-16 p, mean 1 1 p). Laesurae distinct, simple, straight, length three-quarters of, to almost equal to, spore-body radius. Distal hemisphere bears conspicuous, widely spaced, relatively low, broad, smooth, rounded muri, which are connected in several places to each other and to the cingulum, but do not form a constant, symmetrical pattern ; muri slightly sinuous. G. PLAYFORD: LOWER CARBONIFEROUS MICROFLORAS 635 breadth 8-17 p., height 4-7 p. Apart from muri, exine laevigate to infrapunctate (oil immersion). Marginal distortion, particularly of muri, common. Dimensions (40 specimens). Overall equatorial diameter 67-11 2 p (mean 86 /x). Thus the Spitsbergen representatives suggest a considerably less restricted size range for the species than that stated by Ishchenko (1956, 1958) as 85-90 p. text-fig. 10. Camera lucida drawings; all magnifications x 500 unless otherwise specified, a, Knoxi- sporites hederatus (Ishchenko) comb, nov.; lateral view; preparation P174/2, 41-2 114-2 (L.1179). b, Lophozonotriletes appendices (Hacquebard and Barss) comb. nov. (x 250); lateral view; preparation P154/5, 53-2 108-7 (L.1190). c, L. variverrucatus sp. nov.; distal surface; preparation PI 75/2, 33-9 109-0 (L.1193). d, Densosporites rarispinosus sp. nov.; distal surface; preparation P145A/1, 25-6 98-0 (L.1162). e, D. aculeatus sp. nov.; distal surface; preparation P164/2, 43-5 93-3 (L.1165). /, Cristati- sporites echinatus sp. nov.; distal surface; preparation P148/1, 31-9 108-9 (L.l 184). Remarks. This species is included within Knoxisporites on the basis of its conspicuous distal sculpture of strongly developed muri together with distinct equatorial girdle. The subgroup Euryzonotriletes Naumova 1939 is an unsatisfactory taxon as it embraces many valid genera, and, as noted by Potonie (1956, p. 87), it appears to lack a type species. Previous records. According to Ishchenko (1956, 1958) this species is confined to sedi- ments of Tournaisian-Lower Visean age in the western extension of the Donetz Basin; and to Tournaisian-Visean strata in the Dnieper-Donetz Basin. Genus lycospora (Schopf, Wilson, and Bentall) Potonie and Kremp 1954 Type species. L. micropapillata (Wilson and Coe) Schopf, Wilson, and Bentall 1944. Affinity. Schopf, Wilson, and Bentall (1944, p. 54) considered that most of the isolated spores conformable with their genus Lycospora represent microspores of arborescent t t 636 PALAEONTOLOGY, VOLUME 5 lepidodendrids. Subsequently, Potonie and Kremp (1954, p. 156) allied the genus with the Lepidophytales, Lepidodendracaeae, and Lepidospermales. Chaloner (19536) obtained microspores conformable with Lycospora from two hetero- sporous lycopod strobili, Lepidostrobus dubius Binney and L. russelianus Binney, both of Upper Carboniferous age. In 1958 Sen reported microspores similar to Lycospora parva Kosanke 1950 from Lepidostrobus goldenbergi Schimper and from L. variabi/is Lindley and Hutton. Lycospora uber (Hoffmeister, Staplin, and Malloy) Staplin 1960 Plate 89, figs. 16, 17 1938 Zonotriletes pusillus (non Ibrahim) Waltz in Luber and Waltz, p. 15; pi. 3, fig. 33, and pi. A, fig. 12. 1941 Zonotriletes pusillus (non Ibrahim) var. gracilis Waltz in Luber and Waltz, p. 35; pi. 7, fig. 1016. 1952 Hymenozonotriletes pusillus (non Ibrahim) Ishchenko, p. 50; pi. 13, fig. 122. 1955 Cirratriradites uber Hoffmeister, Staplin, and Malloy, p. 383; pi. 36, fig. 24. 1957 Hymenozonotriletes pusillus (non Ibrahim) Naumova; Byvsheva, p. 1010. 1960 Lycospora uber (Hoffmeister, Staplin, and Malloy) Staplin, p. 20; pi. 4, figs. 13, 17, 18, 20. Description of specimens. Spores radial, trilete; amb convexly subtriangular, con- formable with spore-body outline. Laesurae distinct, straight, length approximately equal to body radius; accompanied by narrow, more or less prominent lips. Spore body subtriangular with convex sides and rounded apices; finely granulate to finely rugulate/ verrucate (distal sculpture often coarser); sometimes arcuately folded at periphery. Cingulum (‘flange’) narrow, laevigate, often diaphanous; equatorial margin smooth in well-preserved specimens. Dimensions (50 specimens). Overall equatorial diameter 26-39 p (mean 32 p)\ diameter of spore body 19-27 p (mean 23 p). Remarks. The numerous species listed by Staplin (1960, p. 20) as synonymous with Lycospora uber (Hoffmeister, Staplin, and Malloy) is a reflection of the variable nature of this species, which is often extremely abundant in the Spitsbergen samples. L. uber is undoubtedly conspecific with forms incorrectly assigned by Russian authors (Waltz, Ishchenko, Byvsheva, &c.) to Ibrahim’s species, i.e. L. pusil/a (Ibrahim) Schopf, Wilson, and Bentall. Staplin also lists a number of other species, such as L. noctuina Butterworth and Williams 1958 (p. 376; pi. 3, figs. 14, 15), which may well also be representative of L. uber. Certainly much specific subdivision of spores in this category has resulted from their susceptibility to corrosion, and consequent somewhat variable appearance, parti- cularly with respect to spore-body sculpture. As noted by Staplin (1960), a detailed re- appraisal of the types of all species included within Lycospora would seem an essential approach to the problem. Previous records. This species has been recorded by numerous authors from the Russian Carboniferous (Luber and Waltz 1938, 1941; Ishchenko 1952, 1956, 1958; Byvsheva 1957, &c.) and also from the Upper Mississippian of North America (Hoffmeister, Staplin, and Malloy 1955; Hacquebard and Barss 1957; Staplin 1960). Future proven synonymy may show its presence in the Namurian assemblages described by Dybova and Jachowicz (1957) and Butterworth and Williams (1958). As indicated by Ishchenko G. PLAYFORD: LOWER CARBONIFEROUS MICROFLORAS 637 (1958, stratigraphical range table 3), it seems likely that Lycospora uber did not appear until early Visean times; its upper limit of distribution is, however, dependent upon resolution of the taxonomic problems discussed above. Genus cristatisporites Potonie and Kremp 1954 Type species. C. indignabundus (Loose) Potonie and Kremp 1954. Discussion. After critical re-examination of the diplotype, and study of other Upper Carboniferous species of Cristatisporites , Bhardwaj (1957, p. 105) came to the conclu- sion that ‘the spores are cingulate having a narrow, subequatorial, thickened peripheral region comparable in structure and organisation to the cingulum of Densosporites and Lycospora ’. Richardson (1960, p. 58) followed Bhardwaj in including Cristatisporites within the Cingulati, an assignment which is also supported by the Spitsbergen specimens described below. Affinity. Unknown. Cristatisporites echinatus sp. nov. Plate 91, figs, l^t; text-fig. 10/ Diagnosis. Spores radial, trilete; amb convexly subtriangular. Differentiation into central area and cingulum distinct to obscure; cingulum width approximately 15-25 per cent, of amb diameter. Laesurae prominent, elevated, with thickened lips (individually 2-4-5 p wide, and up to 4 p high); extending on to cingulum, often attaining equatorial margin. Conspicuous echinate sculpture restricted to distal hemisphere and equator, comprising small, fairly closely spaced cones or spines, more or less uniformly dis- tributed, and producing serrate equatorial margin. Sculptural elements ± equal in size on any one specimen, bases circular to oval, apices pointed or slightly rounded, usually discrete, occasionally fused in small groups; basal diameter of cones/spines 1 -5—4 /x, length 1 -5-5 p. Proximal hemisphere finely granulate to infrapunctate. Dimensions (25 specimens). Overall equatorial diameter 63-100 p (mean 81 p). Holotype. Preparation P 1 48/3 1 , 39-7 104-2. L.1182. Locus typicus. Triungen (sample G1472), Spitsbergen; Lower Carboniferous. Description. Holotype 92 p overall, width of cingulum 14-21 p; pronounced laesurae (lips 4 p wide) attaining serrate equatorial margin; proximal hemisphere sparsely and unevenly granulate (grana up to 1 p in diameter). In some specimens the distal sculpture shows a gradual, almost imperceptible increase in density towards the equator, so that the cones/spines are fairly closely packed equatorially, and comparatively sparsely dis- tributed in the vicinity of the distal pole. Fusion of these sculptural elements, when encountered, is restricted to the equatorial region, with groups of no more than three. The cingulum usually shows some equatorial decrease in thickness which may be gradual or abrupt; in the latter instance (as with the holotype) a dark ring is evident defining the inner margin of the cingulum. The conspicuous triradiate marks usually appear as uniform, slightly roughened, relatively thick ridges in which dehiscence fissures are frequently not visible. 638 PALAEONTOLOGY, VOLUME 5 Comparison. One of two illustrations given by Luber (1955, pi. 5, fig. Ill) of Lepido- zonotriletes ciliaris (Luber) resembles Cristatisporites echinatus sp. nov., but close similarities are not apparent from either the description (p. 46) or the accompanying figure (pi. 5, fig. 1 12). HymenozonotriJetes praetervisus Naumova 1953 (pi. 4, fig. 8) may be similar, but an accurate comparison is not possible from Naumova’s illustration and brief description. The subgroup Hymenozonotriletes Naumova appears to embrace in- discriminately monosaccate, cingulate, and zonate forms. Genus lophozonotriletes (Naumova) Potonie 1958 Type species. L. lebedianensis Naumova 1953. Affinity. Unknown. Lophozonotriletes rarituberculatus (Luber) Kedo 1957 Plate 91, figs. 8, 9; text-fig. 9b 1941 Zonotriletes rarituberculatus Luber in Luber and Waltz, pp. 10, 30; pi. 1, fig. 5, and pi. 5, fig. 76. 1956 Euryzonotriletes rarituberculatus (Luber) Ishchenko var. triangulatus Ishchenko, p. 51; pi. 8, fig. 104. 1957 Lophozonotriletes rarituberculatus (Luber) Kedo, p. 1166. 1961 Lophozonotriletes triangulatus Hughes and Playford, pp. 35-36; pi. 3, figs. 3-7. Remarks. In 1956 Ishchenko instituted the infraspecific taxon ‘ Euryzonotriletes rari- tuberculatus (Luber) comb. nov. var. triangulatus var. nov.’ Specimens identical to those described by Ishchenko were recorded subsequently from Spitsbergen by Hughes and Playford (1961), who elevated the variety to specific status ‘as it occurs alone in con- siderable numbers in sample B685’. Additional study by the present writer indicates the widespread lateral, and restricted vertical, distribution of this form within Vest- spitsbergen. After the submission (in April 1960) of the Hughes and Playford manuscript, how- EXPLANATION OF PLATE 91 All figures x 500, and from unretouched negatives. Figs. 1-4. Cristatisporites echinatus sp. nov. 1-3, Holotype. Proximal view: 1, high focus; 2, central focus; 3, low focus. 4, Distal surface; preparation PI 75/1, 28-5 113 0 (L.1183). Fig. 5. Lophozonotriletes dentatus Hughes and Playford 1961. Proximal surface; preparation P226/5, 43-3 113-1 (L.1187). Figs. 6, 7. Lophozonotriletes variverrucatus sp. nov. 6, Holotype; proximal surface. 7, Distal surface; preparation M811/1, 40-5 99-6 (L.1192). Figs. 8, 9. Lophozonotriletes rarituberculatus (Luber) Kedo 1957. 8, Proximal surface; preparation P163/7, 26-2 94-6 (L.l 186). 9, Distal surface; preparation P173/10, 30-3 104-2 (L.l 185). Figs. 10, 11. Lophozonotriletes appendices (Hacquebard and Barss) comb. nov. 10, Distal surface; preparation P149A/8, 36-3 104-7 (L.1189). 11, Proximal surface; preparation P149A/1, 17-8 1 13-9 (L.l 188). Figs. 12, 13. Potoniespores delicatus sp. nov. 12, Holotype; proximal surface. 13, Proximal surface; preparation P149A/29, 34-0 106-4 (L. 1203). Figs. 14, 15. Tholisporites foveolatus Hughes and Playford 1961. 14, Proximal surface; preparation P148/40, 36-9 104-0 (L.1200). 15, Distal surface; preparation PI 72/ 1 , 30-0 104-8 (L. 1201). Palaeontology, Vol. 5 PLATE 91 PLAYFORD, Lower Carboniferous microspores G. PLAYFORD: LOWER CARBONIFEROUS MICROFLORAS 639 ever, the important publication of Luber and Waltz (1941) came to hand, and a detailed comparison of the diagnoses given by Luber (1941, p. 10) for the species, and by Ish- chenko (1955, p. 51) for the variety, casts considerable doubt upon the validity of the latter as a distinct morphographical unit. Ishchenko considered his variety distinguish- able on the basis of its ‘uniformly broad border and regular roundly triangular shape’. However, Luber had clearly described Zonotriletes rarituberculatus as being ‘roundly triangular’, and although noting the margin as somewhat irregular and scallop-like, one of her illustrations (pi. 5, fig. 76: redrawn herein as text-fig. 9b) shows a more or less uniform, entire equatorial margin. It is important to note that Ishchenko included Z. rari- tuberculatus Luber in its entirety within the variety, which must itself, on this basis alone, be considered an unwarranted, superfluous institution. Of the other illustration given by Luber (1941, pi. 1, fig. 5), which shows an undulating equatorial margin, numerous parallels exist in the Spitsbergen material; these are usually accountable as the result of either folding or corrosion. Kedo (1957, p. 1166) included Zonotriletes rarituberculatus Luber, one of a number of species she listed as characteristic of the Lower Tournaisian of White Russia, within the category of Lophozonotriletes Naumova. This assignment remains acceptable under the emendation (by Potonie 1958, pp. 27—28) of Naumova’s subgroup (cf. Hughes and Playford 1961, p. 35). L. rarituberculatus (Luber) is a highly distinctive species and is undoubtedly of considerable stratigraphical value (see previous records below). Dimensions (100 specimens). Overall equatorial diameter 50-82 p. (mean 66 f); diameter of spore body 34-59 ju. (mean 47 /x); width of cingulum 5-15 /x (mean 10 p). Previous records. Initially described (Luber in Luber and Waltz 1941) from Upper Devonian of the Timan Peninsula and Kizel region and from the lower horizons of the Tournaisian in the southern Moscow Basin and Voronezh region. Ishchenko (1956) found L. rarituberculatus to be restricted to Tournaisian strata of the western extension of the Donetz Basin, and Kedo (1957, 1958, 1959) to the Malevka horizon (Lower Tournaisian) of White Russia. Byvsheva (1957, 1960) reported its presence in lowermost Carboniferous from the Melekess and Busuluk deep wells and from the Volga-Ural region. Recently Hughes and Playford (1961) described the species from one sample (B685) of the Spitsbergen Lower Carboniferous, the first-reported occurrence outside the U.S.S.R. Lophozonotriletes dentatus Hughes and Playford 1961 Plate 91, fig. 5 Dimensions (30 specimens). Overall equatorial diameter 42-69 /x (mean 55 /x); diameter of spore body 28-48 p (mean 37 /x). Lophozonotriletes appendices (Hacquebard and Barss) comb. nov. Plate 91, figs. 10, 11 ; text-fig. 10 b 1957 Cincturasporites appendices Hacquebard and Barss, p. 25; pi. 3, figs. 10-12. Description of specimens. Spores radial, trilete; amb roundly subtriangular. Laesurae distinct, simple, straight, length approximately equal to spore-body radius. Body sub- triangular with convex sides and rounded apices. Cingulum uniform or somewhat 640 PALAEONTOLOGY, VOLUME 5 variable in width (average 20 ft), laevigate to finely punctate, often exhibiting narrow concentric furrows; inner margin sometimes darker and well defined, probably indicating poleward ‘overlap’ (3—5 /x) on spore body. Prominent distal sculpture consisting of from four to twenty-two large, smooth, rounded projections (verrucae) disposed rather irregularly on spore body and sometimes additionally on inner margin of cingulum; occasional sparse development on infrapunctate proximal surface of spore body. Verrucae subcircular to oval in surface view, basal diameter 8-27 ft, height 6-10 ft; rarely coalescent, most strongly developed around distal pole. Equatorial margin smooth to undulating. Dimensions (44 specimens). Overall equatorial diameter 110-170 ft (mean 137ft); diameter of spore body 69-1 17 ft (mean 90 ft). Remarks. Although generally conformable, the above description diverges slightly from the original diagnosis of Cincturasporites appendices Hacquebard and Barss 1957. The latter authors evidently did not encounter specimens in which the projections are developed proximally as well as (and much more strongly and abundantly) on the distal surface. Furthermore, many of the Spitsbergen representatives possess projections in excess of the ‘three to ten’ stated by Hacquebard and Barss. As discussed previously, Cincturasporites Hacquebard and Barss 1957 appears to be an unsatisfactory taxon of doubtful validity; certainly the ‘overlap’ diagnostic of the genus is recognizable in rather less than half of the specimens described above. On the other hand, the cingulate and conspicuously verrucate nature of the species is in accor- dance with Lophozonotriletes Naumova as emended by Potonie (1958, pp. 27-28). Previous records. From Upper Mississippian coal of the South Nahanni River area. Northwest Territories, Canada (Hacquebard and Barss 1957). Lophozonotriletes variverrucatus sp. nov. Plate 91, figs. 6, 7; text-fig. 10c Diagnosis. Spores radial, trilete; amb convexly subtriangular, finely dentate to almost smooth. Faesurae distinct, simple, straight or slightly sinuous, almost attaining spore- body margin. Spore body usually somewhat lighter in colour than cingulum, which may show gradual, indistinct, equatorial decrease in thickness. Prominent distal sculpture of verrucae and, less commonly, baculae, distributed rather irregularly on both spore body and cingulum. Projections usually discrete, but bases sometimes fused, particularly around inner margin of cingulum; reduced or absent on equatorial region. Projections rather variable in size, shape, and disposition; range 1-7 ft long, 2—12 yu. broad. Proximal hemisphere laevigate or infrapunctate. Dimensions (30 specimens). Overall equatorial diameter 42-68 ft (mean 55 ft); diameter of spore body 23-36 ft (mean 30 ft); width of cingulum 9-16 ft (mean 12 ft). Holotype. Preparation PI 75/3, 48-6 94 0. L. 1 191. Locus typicus. Citadellet (sample G1450), Spitsbergen; Lower Carboniferous. Description. Holotype 56 ft overall, diameter of spore body 34 ft, width of cingulum 1 1 ft; proximal surface of spore body infrapunctate, of cingulum laevigate; whole distal hemisphere, excepting outer margin of cingulum, bearing numerous verrucae, some G. PLAYFORD: LOWER CARBONIFEROUS MICROFLORAS 641 baculae; sculpturing elements 2-7 p long, 2-12 p broad, frequently fused at bases in vicinity of spore body/cingulum junction; equatorial margin practically smooth. Remarks. This cingulate species is included within Lophozonotriletes on the basis of its conspicuously developed verrucate/baculate sculpture. Tt is distinct from L. rari- tuberculatus (Luber), which has less numerous, more regular distal projections. Genus monilospora (Hacquebard and Barss) Staplin 1960 Type species. M. moniliformis Hacquebard and Barss 1957. Discussion. The emendation of the genus Monilospora Hacquebard and Barss 1957 by Staplin (1960, p. 28) is here accepted, since it somewhat clarifies the morphological features, particularly in light of the effects of corrosion. The present writer is in agree- ment with Staplin’s statement that three of the species in Hacquebard and Barss 1957 — Monilospora moniliformis , Tendosporites subcrenatus ( non Waltz), and Densosporites subserratus — perhaps represent different manifestations, due to variable preservation, of the same species. It seems unfortunate that the terms ‘capsula’ and ‘patella' introduced and utilized by Staplin (1960) in relation to the structure of this and other genera ( Murospora , Tendosporites) are not illustrated or defined in any detail, and are without reference to the layers of the spore wall; in their present form the use of such terms would only add to the confusion at present prevailing in palynological terminology. As understood by the present writer, Staplin’s ‘outer hull’ or ‘capsula’ in fact refers to the envelopment of the intexine by the exoexine, which may be equatorially expanded and/or thickened, whereas ‘patella’ (cf. ‘patina’ of Tholisporites Butterworth and Williams 1958, pp. 381— 2; text-fig. 3) implies predominantly distal thickening of the exoexine. Affinity. Unknown. Monilospora triungensis sp. nov. Plate 92, figs. 2, 3 Diagnosis. Spores radial, trilete; amb subtriangular. Laesurae distinct, simple, straight, length approximately three-quarters to four-fifths spore-body radius. Spore body laevigate; subtriangular with broadly rounded apices and concave to almost straight sides. Broad cingulum showing gradual and slight equatorial decrease in thickness which is emphasized by corrosion; irregularly scalloped in outer part. Scalloping may be confined to outermost region or, if coarser, may extend about half-way towards spore- body margin. Dimensions (30 specimens). Overall equatorial diameter 80-117 p (mean 97 /x) ; diameter of spore body 38-66 p (mean 52 p). Holotype. Preparation P145B/36, 38 0 100-9. L.1194. Locus typicus. Triungen (sample G1466), Spitsbergen; Lower Carboniferous. Description. Holotype 92 p overall; cingulum width 19 p, outer margin almost entirely scalloped (indented as much as 10 p), otherwise laevigate; spore body 53 p in diameter, laevigate. The species is characterized by its large size and distinctive cingulum. 642 PALAEONTOLOGY, VOLUME 5 It is possible that the often highly irregular, scallop-like indentations of the cingulum are the result of corrosive action. However, it is important to note in this connexion that the other microfloral elements, contained in both samples (G1466, G636) from which Monilospora triungensis sp. nov. has been recovered, appear exceptionally well pre- served. Comparison. This species resembles Monilospora mutabilis Staplin 1960 (p. 28; p. 6, figs. 1-7, 9) but is consistently larger. Monilospora dignata sp. nov. Plate 92, figs. 4, 5 Diagnosis. Spores radial, trilete; amb subtriangular to oval. Laesurae distinct, simple, straight, length almost equal to body radius. Spore body subtriangular with straight to convex sides and rounded apices; laevigate to infrapunctate. Cingulum of somewhat variable width (mean 14 yu.) ; including well-defined, continuous, thickened equatorial region, which is elevated, rounded in cross-section, and superficially either laevigate or finely wrinkled; width of marginal thickening typically variable on any given specimen, about 5-10 p. Cingulum otherwise smooth. Dimensions (30 specimens). Overall equatorial diameter 48-64 p (mean 56 p); diameter of spore body 25-36 /x (mean 30 /x). Holotvpe. Preparation P145B/18, 41-0 101-4. L.1197. Locus typicus. Triungen (sample G1466), Spitsbergen; Lower Carboniferous. Description. Holotype 62 p overall; laesurae almost attain spore-body margin; body laevigate, subtriangular with straight to convex sides; cingulum 12-17 p broad; promi- nent, elevated, smooth, marginal thickening (5-9 p in width) appearing to encroach irregularly upon undifferentiated inner part of cingulum. Comparison. Monilospora dignata sp. nov. is distinguishable from M. moniliformis Hacquebard and Barss 1957 (p. 38; pi. 5, figs. 8, 9) in possessing a smaller spore body, longer laesurae, and continuous marginal thickening. Knoxisporites carnosus (Knox) Butterworth and Williams 1958 (p. 369; pi. 2, figs. 8-10) is larger than M. dignata and its spore body is prescribed by a pronounced zone of cingulate thickening. EXPLANATION OF PLATE 92 All figures x 500, and from unretouched negatives. Fig. 1. Cirratriradites Solaris Hacquebard and Barss 1957. Proximal surface; preparation PI 55/ 1 5, 40-3 102-8 (L.1206). Figs. 2, 3. Monilospora triungensis sp. nov. 2, Proximal surface; preparation P145B/34, 34 0 108-5 (L.1195). 3, Holotype; proximal surface. Figs. 4, 5. Monilospora dignata sp. nov. 4, Holotype; proximal surface. 5, Proximal surface; prepara- tion P145B/1, 46-7 99-8 (L.l 198). Figs. 6, 7. Cirratriradites elegans (Waltz) Potonie and Kremp 1956. 6, Proximal surface; preparation P149A/41, 46-2 100-4 (L.1207). 7, Proximal surface; preparation P149A/2, 45-6 95-2 (L. 1 208). Palaeontology, Vol. 5 PLATE 92 J PLAYFORD, Lower Carboniferous microspores G. PLAYFORD: LOWER CARBONIFEROUS MICROFLORAS 643 Infraturma patinati Butterworth and Williams 1958 Genus tholisporites Butterworth and Williams 1958 Type species. T. scoticus Butterworth and Williams 1958. Affinity. Unknown. Tholisporites foveolatus Hughes and Playford 1961 Plate 91, figs. 14, 15 Dimensions (75 specimens). Overall equatorial diameter 52-77 p (mean 64 p); diameter of proximal central area 24-37 p (mean 31 p). Comparison. Densosporites intermedius (Waltz) comb. nov. shows some general resem- blance, but is non-patinate and has different sculpture in the equatorial region. Infraturma zonati Potonie and Kremp 1954 Genus potoniespores Artiiz 1957 Type species. P. bizonales Artiiz 1957. Discussion. In her diagnosis of Potoniespores, Artiiz (1957, p. 254) refers to the presence of a single V-shaped indentation of the equatorial margin. However, this feature may well prove merely a secondary (preservation) effect and hence its significance as a diagnostic characteristic is doubtful. Concise differentiation of the equatorial girdle into an inner thickened portion and an outer membranous zone permits the discrimina- tion of Potoniespores from Murospora (al. Simozonotriletes). Affinity. Unknown. Potoniespores delicatus sp. nov. Plate 91, figs. 12, 13 Diagnosis. Spores radial, trilete; amb subtriangular, conformable with spore-body out- line. Laesurae distinct, simple, straight, length slightly less than spore-body radius. Spore body laevigate to infrapunctate; subtriangular with rounded apices and markedly concave to slightly convex sides. Equatorial girdle entirely laevigate; abruptly and uni- formly differentiated into a prominent, dark, thickened, inner part and a thin, outer, diaphanous zone which is frequently folded and torn. Approximately half to two-thirds of the total girdle width is occupied by the inner thickened portion. Dimensions (35 specimens). Overall equatorial diameter 50-69 p (mean 58 p); diameter of spore body 23-33 p (mean 27 p). Holotype. Preparation P180B/4, 24-7 95-1. L.1202. Locus typicus. Birger Johnsonfjellet (sample G1102), Spitsbergen; Lower Carboniferous. Description. Holotype 54 p overall; body concavely subtriangular, 24 p in diameter, infrapunctate ; equatorial girdle 1 5 p broad, (inner) two-thirds occupied by dark, thickened portion, outer membranous zone with one conspicuous fold. Comparison. Potoniespores bizonales Artiiz 1957 (p. 254; pi. 6, fig. 47) differs from 644 PALAEONTOLOGY, VOLUME 5 P. delicatus sp. nov. in possessing longer laesurae and a relatively broader outer mem- branous zone. Hymenozonotriletes concavus Ishchenko 1956 (p. 63; pi. 12, fig. 134) has a much larger spore body together with somewhat irregular differentiation of the equatorial girdle. Genus cirratriradites Wilson and Coe 1940 Type species. C. saturni (Ibrahim) Schopf, Wilson, and Bentall 1944. Affinity. Microspores showing close resemblance to Cirratriradites anulatus Kosanke and Brokaw (in Kosanke 1950) have been recovered from the herbaceous, heterosporous lycopod Selaginellites suissei Zeiller (Chaloner 1954), and also from the detached, heterosporous strolibus S. erassicinctus Hoskins and Abbott (1956). Cirratriradites Solaris Hacquebard and Barss 1957 Plate 92, fig. 1 Description of specimens. Spores radial, trilete; amb convexly subtriangular, con- formable with spore-body outline. Laesurae distinct, straight, length approximately equal to body radius; bordered by strongly developed lips individually 3—4 yu, wide. Spore-body wall very thick (5-9 p), irregularly punctate to microreticulate. Membranous zona relatively thin, supported by numerous, radially disposed, anastomosing ribs, which tend to be emphasized by corrosion. Well-preserved specimens uncommon. Dimensions (25 specimens). Overall equatorial diameter 1 17-252 /x (mean 189/x); diameter of spore body 55-100 p (mean 78 p). This agrees closely with the combination of the size ranges observed by Hacquebard and Barss (1957) and Staplin (1960). Comparison. Hymenozonotriletes auranthiacus Naumova (Ishchenko 1956, p. 67; pi. 13, fig. 144), recorded also as Zonotriletes auranthiacus (Naumova) Waltz (in Luber and Waltz 1938, p. 16; pi. 3, fig. 40), is undoubtedly a closely related species. It is dis- tinguishable from C. Solaris in its smaller size and in possessing shorter, indistinct, apparently simple laesurae. Previous records. This species has been reported previously from the Upper Mississippian of Canada (Hacquebard and Barss 1957; Staplin 1960). Cirratriradites elegans (Waltz) Potonie and Kremp 1956 Plate 92, figs. 6, 7 1938 Zonotriletes elegans Waltz in Luber and Waltz, p. 15; pi. 3, fig. 32. 1956 Cirratriradites elegans (Waltz) Potonie and Kremp, p. 126. 1958 Hymenozonotriletes elegans (Waltz) Ishchenko, p. 67; pi. 7, fig. 88. Description of specimens. Spores radial, trilete; amb convexly subtriangular, con- formable with spore-body outline. Laesurae distinct, straight; extending on to zona, frequently reaching equator; accompanied by conspicuous, smooth, elevated, thickened lips, having maximum development on spore body, extending 4-6 p on either side of laesurae. Spore body scabrate; non-foveolate. Zona much lighter in colour than spore body, more or less smooth, often folded, shows equatorial decrease in thickness; radially pitted or channelled in corroded specimens. G. PLAYFORD: LOWER CARBONIFEROUS MICROFLORAS 645 Dimensions (45 specimens). Overall equatorial diameter 70-128 p (mean 102^.); diameter of spore body 44-63 p (mean 53 /u.). Previous records. Cirratriradites elegans has been known hitherto only from the U.S.S.R. Waltz (in Luber and Waltz 1938) described it initially from Visean strata of the Moscow Basin, and a recent report is from Visean to Namurian rocks of the Dnieper-Donetz Basin (Ishchenko 1958). Genus camptozonotriletes Staplin 1960 Type species. C. vermiculatus Staplin 1960. Affinity. Unknown. Camptozonotriletes velatus (Waltz) comb. nov. Plate 93, figs. 1-3 1938 Zonotriletes velatus Waltz in Luber and Waltz, p. 14; pi. 3, fig. 35, and pi. A, fig. 18. 1955 Reticulatisporites velatus (Waltz) Potonie and Kremp, p. 112. 1958 Hymenozonotriletes velatus (Waltz) Ishchenko, p. 75; pi. 8, fig. 105. Description of specimens. Spores radial, trilete; amb roundly subtriangular to sub- circular. Laesurae distinct, straight, equal to or slightly less than body radius; simple, or bordered by narrow, thickened, elevated lips which often extend, and diverge markedly, immediately beyond radial termini of laesurae, thus appearing rather ‘spanner-like’ in polar view. Equatorial zone (‘flange’) uniform, lighter in colour than spore body; outer margin smooth or undulating (due to folding), more or less conformable with spore- body equator. Distal surface marked by development of a variable number of dark, thickened ridges of irregular length and disposition, particularly characteristic of spore body but often extending on to zona. Ridges 4-8 p wide, simple or divided equally by a narrow longitudinal channel; sometimes connected to form an irregular, wide-meshed reticulum ; rarely present on proximal surface. Dimensions (100 specimens). Overall equatorial diameter 57-1 16 p (mean 84 p); diameter of spore body 33-88 p (mean 57 p). This extends considerably the size ranges quoted by Waltz (in Luber and Waltz 1938) and Ishchenko (1958). Remarks. The spores described above occur abundantly in the upper horizons of the Lower Carboniferous of Spitsbergen; they conform closely to the descriptions given by Waltz (in Luber and Waltz 1938) and by Ishchenko (1958) of respectively Zonotriletes velatus and Hymenozonotriletes velatus. The assignment of the species to Reticulati- sporites (Ibrahim) by Potonie and Kremp (1955, p. 112) is clearly incorrect. It is here included within Camptozonotriletes Staplin 1960 on the basis of structure (spore with an equatorial flange) and prominent distal sculpture (irregular muri). Previous records. Camptozonotriletes velatus (Waltz) comb. nov. has been recorded hitherto exclusively from the U.S.S.R. Luber and Waltz (1938, 1941) report its occur- rence in Lower Carboniferous strata of the Moscow Basin and Selizharovo and Voronezh regions. According to the work of Ishchenko (1958) the species is present in Upper Devonian and Visean rocks of the Dnieper-Donetz Basin, but apparently absent in the Tournaisian. 646 PALAEONTOLOGY, VOLUME 5 Genus diatomozonotriletes (Naumova) emend. 1939 Diatomozonotriletes Naumova, p. 355; fig. 1. 1956 Reinschospora Schopf, Wilson, and Bentall, /3 section Diatomozonotriletes (Naumova) Potonie and Kremp, pp. 131-2. 1961 Diatomozonotriletes (Naumova) Potonie and Kremp 1956; Hughes and Playford, p. 40. Emended diagnosis. Microspores radial, trilete; spore body triangular or subtriangular in equatorial outline. Laesurae usually well defined and long; simple or accompanied by lips. Spore body almost entirely encompassed by prominent zona (corona) consisting of numerous, strongly developed, mainly discrete saetae (fimbriae) emanating radially from equatorial margin of spore body. Saetae are particularly well developed in central interradial equatorial regions, characteristically exhibiting a gradual diminution in size towards the triangular apices of the spore, where they may be either absent or consider- ably reduced. Saetae pointed or blunt; sometimes fused, at least in part, but always remain recognizable individually within the corona as distinct structural entities. Spore body often sculptured, particularly on distal surface. Type species (here designated). Diatomozonotriletes saetosus (Hacquebard and Barss 1957, p. 41; pi. 6, fig. 3) Hughes and Playford 1961. Other species. The following species are now included within Diatomozonotriletes (Naumova) emend. 1. Diatomozonotriletes ( al . Reinschospora) cervicornutus (Staplin 1960, p. 24; pi. 5, figs. 1-3) comb, nov. Occurrence: Canada (after Staplin 1960) — Golata formation, Alberta; Upper Mississippian. 2. Diatomozonotriletes (al. Zonotriletes) curiosus ( partim ) (Waltz in Luber and Waltz 1938, pi. 4, fig. 49; non pi. A, fig. 13) Ishchenko 1956. Occurrence: U.S.S.R. (after Luber and Waltz 1941) — Moscow Basin, Kizel, Selizharovo, and Voronezh regions; Lower Carboniferous. U.S.S.R. (after Ishchenko 1956, 1958) — western Donetz Basin, Dnieper-Donetz Basin; Visean. 3. Diatomozonotriletes hughesii sp. nov. 4. Diatomozonotriletes (al. Reinschospora) jubatus (Staplin 1960, p. 23; pi. 5, figs. 7, 8) comb. nov. Occurrence: Canada (after Staplin I960) — Golata formation, Alberta; Upper Mississippian. 5. Diatomozonotriletes (al. Reinschospora) nahannensis (Hacquebard and Barss 1957, p. 41; pi. 6, figs. 1, 2) comb. nov. Occurrence: Canada (after Hacquebard and Barss 1957) — South Nahanni River area, Northwest Territories; Upper Mississippian. 6. Diatomozonotriletes (al. Reinschospora sect. Diatomozonotriletes) radforthi (Potonie 1956, p. 69; pi. 9, fig. 90) comb. nov. Occurrence: Canada (after Radforth and McGregor 1954, p. 605) — Wabumun Lake; age uncertain (see Radforth and McGregor 1956, footnote on pp. 27-28). 7. Diatomozonotriletes rants sp. nov. 8. Diatomozonotriletes trilinearis sp. nov. 9. Diatomozonotriletes ubertus Ishchenko 1956, p. 100; pi. 19, fig. 242. Occurrence: U.S.S.R. (after Ishchenko 1956, 1958) — western Donetz Basin, Dnieper-Donetz Basin; Visean to Lower Namurian. 10. Diatomozonotriletes (al. Zonotriletes) vesicarius (Waltz in Luber and Waltz 1941, p. 30; pi. 5, fig. 78) comb. nov. Occurrence: U.S.S.R. (after Luber and Waltz 1941) — Selizharovo region; Lower Carboniferous. Discussion. In anticipation of the possible eventual recognition of Diatomozonotriletes Naumova as a distinct form-genus, Potonie and Kremp (1956«, pp. 131-2) proposed its subgeneric (‘sectional’) status within the category of Reinschospora Schopf, Wilson, and Bentall. Subsequently, Hughes and Playford (1961) incorrectly attributed generic rank to Diatomozonotriletes (Naumova) Potonie and Kremp 1956 (in Potonie 1956, p. 69), which lacks the designation of a type species. Species recorded recently (by Ishchenko 1956, 1958; Hacquebard and Barss 1957; Staplin 1960; Hughes and Playford 1961), together with those described below, indicate the consistent presence in the Lower Carboniferous of a distinct group of Reinschospora- like spores possessing coronae of rela- tively coarse, strongly developed saetae. On the other hand, Upper Carboniferous representatives of G. PLAYFORD: LOWER CARBONIFEROUS MICROFLORAS 647 Reinschospora, for example the type species R. speciosa (Loose), are characterized by more delicate coronae consisting of a dense aggregation of much finer fimbriae. Such, indeed, is the criterion upon which Potonie and Kremp (1956u) based their sectional subdivision of Reinschospora. Thus the separation of Diatomozonotriletes from Reinschospora is warranted on morphographical grounds and appears also to have definite stratigraphical significance. Comparison. Some species of Anapiculatisporites Potonie and Kremp 1954, for example A. serratus sp. nov., possess a strongly spinose equatorial margin which may simulate the zona of Diatomozonotriletes. In such cases, however, the sculpture visible at the margin represents an equatorial development of the predominantly distal, spinose sculpture of Anapiculatisporites. In Diatomozonotriletes , distal sculpture is subordinate and quite distinct from the structural components of its encompassing zona. The present writer is in agreement with Potonie (1960, p. 60) concerning the "prob- lematical’ nature of Procoronaspora Butterworth and Williams 1958. This genus appears to overlap the connotations of several previously instituted genera, such as Lycospora , but future work may possibly justify its recognition as a discrete form-genus. Procorona- spora is undoubtedly closely related to Diatomozonotriletes (Naumova) emend., but the "fine grade’ of its diverse sculpture ("grains, verrucae, spines, baculae, &c.’) serves to distinguish it from the latter genus. As noted by Potonie (1960, p. 60), Butterworth and Williams’s assignment of Diatomozonotriletes curiosus (Waltz) is incorrect. Affinity. Unknown. Diatomozonotriletes saetosus (Hacquebard and Barss) Hughes and Playford 1961 Plate 93, figs. 4-7 1938 Zonotriletes speciosus (non Loose) Waltz in Luber and Waltz, pp. 14-15; pi. 4, fig. 48, and pi. A, fig. 9. 1956 Diatomozonotriletes speciosus ( non Loose) Ishchenko, pp. 99-100; pi. 19, figs. 239-41. 1957 Reinschospora saetosus Hacquebard and Barss, pp. 41-42; pi. 6, fig. 3. 1961 Diatomozonotriletes saetosus (Hacquebard and Barss) Hughes and Playford, p. 40; pi. 4, figs. 14, 15. Description of specimens. Spores radial, trilete; spore body subtriangular with concave sides and rounded to truncated apices. Laesurae distinct, straight, extending almost to equatorial margin; simple or bordered by narrow, slightly thickened lips. Prominent corona comprising nine to fifteen discrete, typically pointed saetae projecting laterally from each interradial portion of the spore-body equator. Saetae 2-5-5 /x broad at base, 3-22 p long; attain maximum length in central interradial region, diminishing uniformly towards smooth triangular apices. Spore body usually entirely laevigate, occasionally finely granulate on distal surface. Exine thick (2-4 f), often distinctly thinner at apices. Dimensions (85 specimens). Equatorial diameter of spore body 36-63 p (mean 49 p). Holotype. As designated by Hacquebard and Barss (1957, p. 42). Locus typicus. South Nahanni River area, Northwest Territories, Canada (after Hacquebard and Barss 1957); Upper Mississippian. Previous records. Diatomozonotriletes saetosus has been recorded extensively from the U.S.S.R., as follows: Lower Carboniferous of the Moscow Basin and of the Selizharovo, Borovichi, and Kizel regions (Luber and Waltz 1938, 1941); Lower Visean only of the 648 PALAEONTOLOGY, VOLUME 5 western Donetz Basin (Ishchenko 1956); Lower Carboniferous of the Melekess and Busuluk deep wells (Byvsheva 1957); Visean-Namurian of the Dnieper-Donetz Basin (Ishchenko 1958); Yasnopolyansky substage (Lower Visean) of the Saratov-Stalingrad Volga area (Loginova 1959); and Lower Carboniferous of the Volga-Ural region (Byvsheva 1960). Note that these Russian authors invariably incorrectly assign this species to Loose’s species, i.e. Reinschospora speciosa (Loose) Schopf, Wilson, and Bentall. Hacquebard and Barss (1957) described the species from the Upper Mississippian of text-fig. 11. Camera lucida drawings; all magnifications x 500. a, Velosporites microreticulatus sp. nov.; proximal surface; preparation P163/7, 49-6 110-7 (L.1236). b, Spinozonotriletes balteatus sp. nov. ; proximal surface; preparation P149A/3, 42-4 105-8 (L.1244). c, Radialetes costatus gen. et sp. nov.; preparation P159/5, 48-0 112-5 (L.1252). d, Diatomozonotriletes trilinearis sp. nov.; distal surface; preparation P149A/2, 26-9 108-5 (L.1227). e, D. rarus sp. nov.; distal surface; prepara- tion P145B/2, 43-6 110-9 (L.1230). /, D. hughesii sp. nov.; distal surface; preparation P149B/1, 44-6 104-5 (L.1223). Canada (see above), and Hughes and Playford (1961) reported some specimens from the Lower Carboniferous (sample B609) of Spitsbergen. Diatomozonotriletes hughesii sp. nov. Plate 93, figs. 8-1 1 ; text-fig. 1 1 / Diagnosis. Spores radial, trilete; amb subtriangular with rounded apices and concave to almost straight sides. Laesurae perceptible to distinct, simple, more or less straight, almost attaining equatorial margin. Well-developed corona consisting of eleven to seven- teen large, mutually dissociated, uniformly tapering saetae projecting laterally from each side of the triangular amb, and having pointed, rarely divided apices. Saetae reach maximum size on centres of sides (up to 16 p. long and 4 p in basal diameter); absent or commonly reduced to small coni on triangular apices of spore body. Distal surface of spore body distinctly echinate, bearing scattered, somewhat irregularly distributed G. PLAYFORD: LOWER CARBONIFEROUS MICROFLORAS 649 spines (length 2-6 p); bases of spines rather bulbous (diameter 1-2 p). Proximal surface laevigate. Exine 1 -5-2 p thick. Dimensions (80 specimens). Equatorial diameter of spore body 30-47 p (mean 39 p). Holotype. Preparation P149B/1, 47-3 107-6. L. 1218. Locus typicus. Triungen (sample G1470), Spitsbergen; Lower Carboniferous. Description. Holotype body diameter 46 p; saetae (interradial) 5-15 p long; triangular apices of amb each bearing four to five coni, 2-3 p long, 1-5 p broad at base; distal spinae congregated in polar region, relatively sparse elsewhere, average length 5 p; exine 2 p thick. This species is characterized by distinctly echinate distal sculpture, together with frequent development of small coni on the radial corners of the spore body. Comparison. Diatomozonotriletes euriosus (Waltz) Ishchenko (1956, pp. 100-1; pi. 19, fig. 243) and 1 Reinsehospora sp. A’ of Staplin (1960, p. 24; pi. 5, fig. 18) have finer, more numerous saetae. Diatomozonotriletes trilinearis sp. nov. Plate 93, figs. 12-14; text-fig. 11 d Diagnosis. Spores radial, trilete; amb subtriangular with straight to slightly concave sides, and rounded to truncated apices. Laesurae distinct, simple, straight, almost reaching equatorial margin. Seventeen to twenty-six closely spaced saetae project radially from sides of spore body amb constituting prominent corona, which is not developed at triangular apices. Saetae pointed, occasionally divided, mutually dis- sociated, basal diameter T5-2 p, longest in central interradial region (up to 14 p), exhibiting a slight, gradual reduction in size towards smooth apices of spore body. Distal surface bearing sharply tapered spinae, 2-4 p long, T5-2 p broad at base, charac- teristically congregated in a Y-shaped area, the orientation and radial extent of which conforms with that of the trilete mark on the opposite surface. Each limb of the ‘ Y ’ often consists of two parallel lines of spinae. Apart from this restricted spinose sculpture, spore body laevigate. Exine 1 -5-2-5 p thick. Dimensions (45 specimens). Equatorial diameter of spore body 35-56 p (mean 45 p). Holotype. Preparation P149A/2, 33-5 95-6. L.1224. Locus typicus. Triungen (sample G1470), Spitsbergen; Lower Carboniferous. Description. Holotype body diameter 50 p; coronal saetae 4-13 p long, less than 1 p apart; constituent spinae of Y-shaped, distal, sculptured area are less closely spaced in polar region. Comparison. Type 63 of Reinsch (1884, p. 7; pi. 2, fig. 27) from the Russian (? Lower) Carboniferous may be conspecific with Diatomozonotriletes trilinearis sp. nov. Diatomozonotriletes rarus sp. nov. Plate 93, figs. 15, 16; text-fig. lie Diagnosis. Spores radial, trilete; amb subtriangular with slightly convex to slightly concave sides and rounded apices. Laesurae distinct, straight, length three-quarters of, 650 PALAEONTOLOGY, VOLUME 5 to almost equal to, spore-body radius; bordered by thickened, slightly elevated lips, individually about 2 p wide. Equatorial corona consisting of discrete, closely spaced, pointed saetae attaining maximum size interradially (3-5-5 p long, 1-5-2 p in basal diameter) and diminishing gradually and uniformly towards the smooth triangular apices. Proximal surface of spore body laevigate; distal surface echinate, with numerous, small, fairly evenly distributed coni, 1 -5—2 /x long, 1-1-5 p broad at base, and 1-5-4 p apart. Exine (excluding sculpture) up to 1 p thick. Dimensions (15 specimens). Equatorial diameter of spore body 37-48 p (mean 42 p). Holotype. Preparation P145B/19, 38-3 103-4. L.1228. Locus typicus. Triungen (sample G1466), Spitsbergen; Lower Carboniferous. Description. Holotype body diameter 39 p; distal coni reduced in size and density in equatorial region; laesurae conspicuously labiate. This distinctive but very rare species is characterized by relatively short, pointed, equatorial saetae, distal echinate sculpture, together with marked lip development. Comparison. Diatomozonotriletes rarus sp. nov. is similar to D. curiosus (Waltz in Luber and Waltz 1938, pi. 4, fig. 49) Ishchenko 1956, which is distinguishable, however, in possessing longer saetae and simple laesurae. Anteturma pollenites R. Potonie 1931 Turma saccites Erdtman 1947 Subturma monosaccites (Chitaley) Potonie and Kremp 1954 Infraturma triletesacciti Leschik 1955 Subinfraturma intrornati Butterworth and Williams 1958 Discussion. Butterworth and Williams’s (1958) suprageneric subdivision of mono- saccate grains on the basis of predominantly either internal or external sculpture is EXPLANATION OF PLATE 93 All figures x 500, and from unretouched negatives. Figs. 1-3. Camptozonotriletes velatus (Waltz) comb. nov. 1, Proximal surface; preparation PI 64/ 1 5, 32-2 101-5 (L.1210). 2, Distal surface; preparation P149A/27, 38-7 104-4 (L. 121 1). 3, Proximal surface; preparation P157/4, 23-6 113-6 (L.1212). Figs. 4-7. Diatomozonotriletes saetosus (Hacquebard and Barss) Flughes and Playford 1961. 4, Proxi- mal surface; preparation P167B/10, 35-9 104-0 (L. 1215). 5, Proximal surface; preparation P167B/4, 35-5 100-7 (L. 1214). 6, Proximal surface; preparation P167A/2, 25-3 110-3 (L.1216). 7, Proximal surface; preparation P127/3, 53-7 96-9 (L.1217). Figs. 8-11. Diatomozonotriletes Imghesii sp. nov. 8, Proximal surface; preparation P149A/1, 28-2 113-3 (L. 1219). 9, Proximal surface; preparation P149A/35, 32-7 102-0 (L.1220). 10, Holotype; distal surface. 11, Distal surface; preparation P157/2, 18-9 108-5 (L.1222). Figs. 12-14. Diatomozonotriletes trilinearis sp. nov. 12, Holotype; proximal surface. 13, Distal surface; preparation P149B/1, 15-5 99-8 (L. 1 225). 14, Proximal surface; preparation P149B/2, 38-5 97-4 (L.1226). Figs. 15, 16. Diatomozonotriletes rarus sp. nov. 15, Holotype; proximal surface. 16, Distal surface; preparation P145C/1, 30-3 106-6 (L. 1 229). Figs. 17, 18. Endosporites micromanifestus Hacquebard 1957. 17, Proximal surface; preparation P145B/2, 24-5 94-3 (L.1232). 18, Proximal surface; preparation P174/2, 25-5 1 12-0 (L.1231). Palaeontology , Vol. 5 PLATE 93 PLAYFORD, Lower Carboniferous microspores G. PLAYFORD: LOWER CARBONIFEROUS MICROFLORAS 651 undoubtedly of morphographical significance. However, in many cases the distinction is not readily ascertainable. Although Butterworth and Williams (1958) assigned their genus Remysporites to the Extrornati, Potonie (1960, p. 72) included it within the Intrornati since he considered that the often ‘externally microreticulate’ bladder ap- pearance of this genus may well be due to the development of infrareticulate structure rather than to external sculpture of the exoexine. According to Potonie similar mani- festation of internal bladder structure is evident in other genera ( Endosporites , Wilsonia , Guthorlisporites, Microsporites). Hence, Velosporites Hughes and Playford 1961, which shows ‘fine external sculpture’ of the saccus, is also probably more correctly included within the Intrornati. Genus endosporites Wilson and Coe 1940 Type species. E. ornatus Wilson and Coe 1940. Discussion. Richardson (1960, p. 49) has with justification drawn attention to the over- lapping connotations of Auroraspora Hoffmeister, Staplin, and Malloy 1955 and Endosporites Wilson and Coe 1940. However, Richardson’s statement that Auroraspora ‘differs from Endosporites in the absence of a limbus’ is questionable, since the original diagnosis of the latter genus (Wilson and Coe 1940, p. 184), which is still accepted un- emended, and a recent morphological amplification of the type species (Wilson 1960) contain no reference to an equatorial bladder thickening (limbus). Admittedly, some authors (Potonie and Kremp 1954; Bhardwaj 1957; Chaloner 1953a, 19586) have noted the characteristic presence of a limbus in representatives of Endosporites , and it is un- doubtedly an important morphographical feature which may well have generic signi- ficance. However, there are many species included within Endosporites , and presently recognized as such, which appear to lack the development of a limbus. In all, therefore, a complete reappraisal of the type species of this and other related monosaccate genera (particularly Auroraspora) would seem advisable. Pending this, the present writer con- siders it preferable at this stage to retain the original generic assignment of the two species instituted by Hacquebard (1957), E. micromanifestus and E. macromanifestus , both of which Richardson (1960) transferred to Auroraspora. Perhaps the least unsatisfactory distinction between Auroraspora and Endosporites was expressed by Hoffmeister, Staplin, and Malloy (19556, p. 381) on the basis of rela- tive thicknesses of bladder and body walls. According to these authors Auroraspora possesses a central body having a ‘moderately thick wall’ enclosed by a ‘transparent and very thin bladder’; whereas in Endosporites the body wall ‘approximates the bladder in thickness’ (cf. Wilson 1960, pi. 1, fig. 5 — explanation p. 31). As Richardson (1960, p. 49) implies, little diagnostic importance can be attached to actual or relative colour which is partially dependent upon preservation and maceration procedures. Wilson (1960) has demonstrated conclusively that in Endosporites ornatus the central body is attached to the bladder on the proximal side only; this method of attachment was interpreted earlier by Potonie and Kremp (1954, p. 149; fig. 81). Affinity. Chaloner (1953a, 19586) has reported the occurrence of microspores very similar to Endosporites globiformis (Ibrahim) Schopf, Wilson, and Bentall 1944 in the lycopod cone Polysporia mirabilis Newberry 1873 (syn. Lepidostrobus zea Chaloner 1953a). Earlier, Schopf, Wilson, and Bentall (1944, p. 45) stated that ‘ Endosporites is 652 PALAEONTOLOGY, VOLUME 5 related to some of the Pennsylvanian Cordaitaleans’ because of the presence of E. pelucidus- type spores within the strobilus Cordaianthus shuleri Darrah 1940. This attribution of Endosporites has been discounted by Wilson (1960, p. 31) because he has shown that E. pelucidus is more correctly assigned to the genus Florinites (see Wilson 1958). Endosporites micromanifestus Hacquebard 1957 Plate 93, figs. 17, 18 1956 Hymenozonotriletes aff. variabilis Naumova; Ishchenko, p. 62; pi. 11, figs. 129, 130. 1957 Endosporites micromanifestus Hacquebard, p. 317; pi. 3, fig. 16. 1960 Auroraspora micromanifestus (Hacquebard) Richardson, p. 51. Description of specimens. Spores radial, trilete; amb convexly subtriangular. Laesurae distinct, accompanied by elevated, rather irregular, flange-like lips that frequently extend to the equator. Central body thin, smooth, well defined; outline more or less conformable with amb. Bladder thin, often folded, infragranulate. Dimensions (50 specimens). Overall equatorial diameter 42-95 /x (mean 67 /x); diameter of central body 28-65 p (mean 44 f). Previous records. Described initially by Hacquebard (1957) from lowermost Misissip- pian strata of Nova Scotia, this species has been recorded subsequently from the Scottish Visean by Love (1960) and from one sample (B685) of the Lower Carboniferous of Spitsbergen (Hughes and Playford 1961). It evidently occurs also throughout the Tournaisian-Visean-Namurian succession of the western extension of the Donetz Basin (Ishchenko 1956, p. 62). Genus remysporites Butterworth and Williams 1958 Type species. R. magnificus (Horst) Butterworth and Williams 1958. Discussion. Contrary to the statement of Butterworth and Williams (1958, p. 386), the saccus in this genus is now considered to envelop the central body entirely (see dis- cussion herein of Veiosporites). Affinity. Affinity with the Cycadofilices is suggested by the similarity between the type species and the spores borne by Paracaiathiops stachei (Stur) Remy 1953 (see Butter- worth and Williams 1958, p. 387; Potonie 1960, p. 72). Remysporites albertensis Staplin 1960 Plate 94, fig. 3 Description of specimens. Spores radial, trilete; amb and body outline subcircular to circular. Smooth central body completely enveloped by loosely fitting bladder; both commonly folded, and probably attached at conspicuous proximal polar (contact) area. Contact area convexly subtriangular, distinctly sculptured with mixed rugulae and verrucae; bladder surface otherwise smooth. Central body and bladder walls both thin (about 1—1-5 yu.). Laesurae distinct, simple, straight, length half to two-thirds central body radius. G. PLAYFORD: LOWER CARBONIFEROUS MICROFLORAS 653 Dimensions (25 specimens). Overall equatorial diameter 146-205 p (mean 178 /x) : diameter of central body 1 13-1 50 /x (mean 1 30 yu.). Comparison. The specimens conform closely with the diagnosis given by Staplin (1960, p. 35), except that they extend the size range considerably. However, Staplin does not state the number of specimens he measured, and in any case it seems likely that such large monosaccate species exhibit considerable size diversity, dependent probably upon mode of preservation and/or maceration (cf. Butterworth and Williams 1958, p. 388). Previous records. From the Golata formation (Upper Mississippian) of Alberta, Canada (Staplin 1960). Genus velosporites Hughes and Playford 1961 Type species. V. echinatus Hughes and Playford 1961. Discussion. This genus includes large monosaccate spores (as diagnosed by Hughes and Playford 1961, p. 42) characterized by relatively minor but distinctive body-wall sculpture. It is also important to state that a limbus may or may not be present. According to Butterworth and Williams (1958, p. 386) the genus Remysporites is characterized by ‘bladder enveloping central body except on proximal side’; and it was principally on this basis that Hughes and Playford (1961) decided to erect the genus Velosporites to incorporate a species rather similar to Remysporites magnificus (Horst) Butterworth and Williams but possessing comprehensive bladder envelopment. Recently, however, through the courtesy of Drs. M. A. Butterworth and A. H. V. Smith of the National Coal Board, the opportunity has been taken of examining the material from which Butterworth and Williams diagnosed Remysporites. As a result the present writer came to the conclusion — jointly with Dr. Butterworth — that the bladder in R. magnificus (the type species) does, in fact, envelop the central body entirely. This is substantiated further by a more recently described representative of Remysporites, R. albertensis Staplin 1960 (p. 35; pi. 8, figs. 8, 10), which is also recorded herein. The characteristic sculpture and relatively thick wall of the central body, exhibited by the two species recorded below, is, however, considered sufficient to justify the continued recognition of Velosporites as a distinct form-genus. Affinity. Unknown. Velosporites echinatus Hughes and Playford 1961 Plate 94, fig. 1 Remarks. The surface of the central body characteristically bears minute, sparsely dis- tributed coni or very low, mound-like elevations, which are often evident only under oil immersion. The bladder is commonly folded on both large and small scale, the latter resulting in a microrugulate effect. Dimensions (80 specimens). Overall equatorial diameter 102—194 yu. (mean 140 p)\ diameter of central body 70-128 /x (mean 100 p). 654 PALAEONTOLOGY, VOLUME 5 VeJosporites mieroreticulatus sp. nov. Plate 94, fig. 2; text-fig. 1 la Diagnosis. Spores radial, trilete; monosaccate; amb circular to oval, more or less entire. Laesurae simple, straight, length approximately four-fifths central body radius, not evident on bladder. Central body distinct, circular to subcircular, thick-walled (4-9 p); distinct, finely reticulate sculpture of very narrow, pointed muri up to 1 -5 /u. high, enclosing small, polygonal lumina which are 1-5-7 /x broad (average 3-5 /x); surrounded completely by thin, transparent bladder. Bladder extending 9-27 p, beyond central body margin; definite equatorial thickening (limbus) 3-6-5 p wide, smooth, imposing com- parative rigidity to bladder. Bladder often densely microrugulate or vermiculate, frequently corroded or torn, thickness about 0-5 /x. Dimensions (16 specimens). Overall equatorial diameter 100-140 p (mean 118 yu.) ; diameter of central body 73-102 /x (mean 88 /x). Holotype. Preparation P163/7, 22-3 94-7. L.1235. Locus tvpicus. Birger Johnsonfjellet (sample G1089), Spitsbergen; Lower Carboniferous. Description. Holotype 120 p overall, subcircular; central body 92 p in diameter, 5 p in thickness, circular, colour much darker than bladder; bladder partially removed thereby revealing detail of conspicuous microreticulate sculpture of central body; limbus 6 p wide. Subturma polysaccites Cookson 1947 Genus alatisporites Ibrahim 1933 Type species. A. pustulatus Ibrahim 1933. Affinity. Unknown. Alatisporites tessellatus Staplin 1960 Plate 95, fig. 10 Description of specimens. Spores radial, trilete. Central body circular, finely and densely rugulate. Laesurae indistinct, simple, straight, length half to two-thirds body radius. Approximately seven to eight thin, overlapping, frequently strongly folded bladders are prominent equatorially but attached to distal surface of body. Dimensions (17 specimens). Overall equatorial diameter 75-109 p (mean 87 /x); body diameter 52-61 /x (mean 56 /x). EXPLANATION OF PLATE 94 All figures X 500, and from unretouched negatives. Fig. 1. Velosporites echinatus Hughes and Playford 1961. Proximal surface; preparation M811/5, 58-2 108-9 (L.1234). Fig. 2. Velosporites mieroreticulatus sp. nov. Holotype; proximal surface. Fig. 3. Remysporites albertensis Staplin 1960. Proximal surface; preparation P149A/15, 40-4 100-1 (L.1233). ’ Figs. 4-6. Spinozonotriletes uncatus Hacquebard 1957. 4, Proximal surface; preparation P175/2, 42-8 108-9 (L.1238). 5, Proximal surface; preparation P148/5, 38-8 93-0 (L.1240). 6, Distal surface; preparation P148/51, 39-1 107-0 (L.1237). Palaeontology, Vol. 5 PLATE 94 PLAYFORD, Lower Carboniferous microspores G. PLAYFORD: LOWER CARBONIFEROUS MICROFLORAS b55 Remarks. Apart from extending the range of overall size, the Spitsbergen specimens conform very closely to the diagnosis given by Staplin (1960, p. 31; pi. 7, fig. 10). Previous records. Described initially from the Golata formation (Upper Mississippian) of Alberta, Canada (Staplin I960). Turma aletes Ibrahim 1933 Subturma azonaletes (Luber) Potonie and Kremp 1954 Infraturma reticulonapiti (Erdtman) Vimal 1952 Genus retialetes Staplin 1960 Type species. R. radforthii Staplin 1960. Discussion. In his diagnosis of this genus, Staplin (1960, p. 6) states: ‘spores alete, but sometimes split along a few fine grooves that originate at one end and parallel the long axis’. Similar but usually more extensive splitting has been observed in certain Mesozoic microspores, e.g. Schizosporis Cookson and Dettmann 1959 and Psophosphaera Naumova (in Bolkhovitina 1959). In Retialetes, rupturing, when present, is always longitudinally situated, and suggests a possible mechanism for germination. Affinity. Unknown. Retialetes radforthii Staplin 1960 Plate 95, figs. 1-3 Description of specimens. Spores alete, ellipsoidal. Comprehensive reticulate sculpture comprised of rounded or flat-topped, low, smooth muri (1-3^. high, 1-2-5 p broad) enclosing subcircular to polygonal lumina 4-22 p in longest diameter (usually about 8 p). Exine (excluding muri) 3-5 p thick; often split along one, occasionally two or more, narrow grooves that parallel the long axis of the spore. Dimensions (25 specimens). 102-182 p (mean 144 p) by 66-107 p (mean 84 p). Previous records. This distinctive species was originally described by Staplin ( 1 960) from the Upper Mississippian Golata formation of Alberta, Canada. Genus radialetes gen. nov. Type species. R. costatus sp. nov. Diagnosis. Microspores radial, alete. Outline circular or subcircular. Distinctive sculp- ture consisting of radially disposed muri or incipient thickenings which thus give the spores an overall radiating appearance. Muri sometimes considerably diminished towards central portions of spores. Comparison. The spore illustrated by Hoffmeister, Staplin, and Malloy (1955a, pi. 3, fig. 7) as ‘ Radiaspora" sp. has similar, albeit exclusively distal, sculpture but differs from Radialetes gen. nov. in being distinctly trilete. As noted by Potonie (1956, p. 42), Radia- spora has yet to be validated as a generic name. Radialetes is distinct from Aumanci- sporites Alpern 1958 (p. 84), which is sculptured with more or less parallel grooves dis- posed transversely with respect to the long axis of the spore. Undulatasporites Leschik 1955 (p. 28) has irregular rugulate sculpture. Affinity. Unknown. 656 PALAEONTOLOGY, VOLUME 5 Radialetes costatus sp. nov. Plate 95, figs. 7-9; text-fig. 11c Diagnosis. Spores radial, alete. Outline circular to subcircular; commonly distorted due to folding. Both surfaces sculptured with more or less distinct, low, non-anastomosing, radially disposed muri which attain maximum development at the margin, and may be lacking or considerably diminished centrally; muri 1 -5—5 yu, broad, 1—3 yu. apart, up to 2 p high. Folding of exine usually results in marked apparent discordance of muri on opposing surfaces producing an overall ‘cross-hatched’ effect. Exine (including sculp- ture) 2-6 p thick; apart from muri, laevigate to finely granulate or punctate. Dimensions (50 specimens). Diameter 42-1 17 /x (mean 70 /x). Holotype. Preparation P145B/38, 40-7 105-9. L.1249. Locus typicus. Triungen (sample G1466), Spitsbergen; Lower Carboniferous. Description. Holotype 48 p, circular; conspicuous radial muri 1-5-3 /x broad, 1—1-5 p high, 1 -5-3 p apart; muri do not extend to central portion of either surface; exine other- wise laevigate, total thickness 2 p. Remarks. This distinctive, alete species, characterized by simple, radially disposed muri, has not been recorded in available literature. It shows considerable size variation, but is otherwise morphographically constant. R. costatus sp. nov. occurs in many of the Spits- bergen Lower Carboniferous samples, but is always a minor constituent. INCERTAE SEDIS Genus spinozonotriletes Hacquebard 1957 Type species. S. uncat us Hacquebard 1957. Discussion. This and several other genera were instituted by Hacquebard (1957, pp. 314-15) as convenient subdivisions of the broad subgroup Archaeozonotriletes Naumova 1953. Both Naumova and Hacquebard used the term ‘perispore’ to denote the usually strongly developed, often conspicuously sculptured outer membrane which encloses and frequently almost obscures the central body of many of the spores embraced by the subgroup. It is, however, highly questionable whether a true perispore (perine), as usually understood (cf. Erdtman 1952; Harris 1955), is represented. Potonie (1960, p. 42) suggested that the ‘central body’ seen in Spinozonotriletes may be a mesospore, a feature which, according to Potonie (1958, p. 21), is present also in the type species of Grandispora Hoffmeister, Staplin, and Malloy 1955. From text-figs. 5, 6c of Richardson (1960) it is evident that his genus Ancyrospora shows wall features similar to those of Spinozonotriletes. Richardson (p. 55) applied the term ‘bladder’ to the thick, strongly sculptured, outer membrane (which he regarded as the exoexine) enveloping the central body (intexine), and thus assigned Ancyrospora to the Monosaccites. There seems to be considerable doubt, however, as to whether the outer enveloping layer of the exine in these spores is truly comparable to the exoexine (bladder) of typical Palaeozoic monosaccate types (e.g. Endosporites, Remysporites, Ve/osporites). Thus until further work is done on the structure of such forms as Spino- zonotriletes, their non-committal suprageneric assignment seems preferable. G. PLAYFORD. LOWER CARBONIFEROUS MICROFLORAS 657 Grandisporci was described by Hoffmeister, Staplin, and Malloy (1955) as possessing a ‘central body wall only slightly thicker than the bladder wall’, a feature which together with its constantly subcircular amb permits clear discrimination from Spinozonotriletes. Affinity. Unknown. Spinozonotriletes uncatus Hacquebard 1957 Plate 94, figs. 4-6 Description of specimens. Spores radial, trilete; amb convexly subtriangular. Laesurae with prominent, folded, flange-like lips (up to 5 p wide and 7 p high) extending to equator. Exoexine conspicuously sculptured with large, simple spines which are parti- cularly frequent around the equatorial regions, less abundant in the polar areas; some specimens were noted in which the spines were reduced or absent on finely granulate contact areas. Spines have broad, circular bases (2-6 p wide) which often appear rather bulbous in lateral view; length 4-19 p. This wide variation in spine dimensions is between specimens rather than within specimens, which individually bear spines of markedly uniform size. Exoexine thickness 3-5-5 p (exclusive of spines); commonly folded. Intexine rather indistinct, more or less conformable with equatorial outline, diameter roughly three-quarters overall diameter. Dimensions (66 specimens). Overall equatorial diameter (exclusive of spines) 74-150 p (mean 104 p). This is closely conformable with the size range stated by Hacquebard (1957, p. 316). Comparison. Spinozonotriletes uncatus may be conspecific with Acanthozonotriletes senticosus Ishchenko 1956 (p. 87; pi. 16, fig. 200), which is somewhat smaller (67-70 p), but is otherwise very similar. Previous records. From the Horton group (lowermost Mississippian) of Nova Scotia, Canada (Hacquebard 1957). The possibly identical species Acanthozonotriletes senticosus is confined to Tournaisian strata of the western Donetz Basin (Ishchenko 1956). Spinozonotriletes balteatus sp. nov. Plate 95, figs. 4-6; text-fig. Mb Diagnosis. Spores radial, trilete; amb roundly subtriangular to oval. Laesurae obscured by elevated, narrow, membranous, flange-like lips, frequently contorted due to com- pression and extending to limbate equatorial margin. Intexine indistinct to perceptible, roundly subtriangular. Distal surface of exoexine densely and uniformly sculptured with small, simple spinae which sometimes coalesce to form a rugulate pattern; spines usually evident at equator, sparsely scattered to absent on proximal surface. Spines have rounded to polygonal bases (diameter 0-5-2-5 p); length 1-2 p. Equatorial margin of exoexine marked by well-defined limbus 3-5-7 p broad in polar view. Dimensions (40 specimens). Overall equatorial diameter 51-102 p (mean 73 p)\ diameter prescribed by intexine 30-59 p (mean 42 p). Holotype. Preparation P149A/3, 30-5 97-5. L.1241. Locus typicus. Triungen (sample G1470), Spitsbergen; Lower Carboniferous. 658 PALAEONTOLOGY, VOLUME 5 Description. Holotype 77 p overall, irregularly roundly subtriangular; sinuous laesurate lips extend to conspicuously limbate margin; intexine perceptible, 44^ in diameter; distal surface of exoexine covered with small, crowded spinae which are often coalescent at their bases; apart from spines, exoexine laevigate. Obliquely compressed specimens common; in such cases the limbus appears as a well-defined, dark, transgressive band, marking the true equatorial margin. Remarks. This species, characterized by the presence of a limbus and of predominantly distal spinose sculpture, appears unparalleled in available literature. On the basis of its exoexinal sculpture and somewhat obscure intexine, the species finds suitable inclusion within Spinozonotriletes Hacquebard. Genus tetraporina Naumova 1939 ex Naumova 1950 Type species. T. antiqua Naumova 1950 (designated by Potonie 1960, p. 130). Discussion. This genus, recently validated by Potonie (1960), was instituted by Naumova (1939, p. 357) as a subgroup of her group Tetraporosa , which she included within the class Porosa Naumova. The original diagnosis of Tetraporina stated ‘pollen with four pores, without folds’, and according to Naumova the class Porosa ‘belongs exclusively to the Angiospermae'. Subsequently, Naumova (1950) and Teteriuk(1956) have described a number of Russian Lower Carboniferous species of Tetraporina, and reaffirmed their belief in the angiospermous affinity of such forms. More recently, the names Azono- tetraporina and Zonotetraporina were introduced by Teteriuk (1958, pi. 1 explanation) merely as captions to some drawings of further Lower Carboniferous Tetraporina-Wkz spores, and must therefore at this stage be considered nomina nuda. Thus Staplin’s (1960, p. 6) usage of Azonotetraporina as a valid generic entity is unacceptable. Furthermore, from the figures given by Teteriuk (1958) it seems likely that the forms were differentiated only on the basis of wall thickness. Tetraporina Naumova is rather an unsatisfactory taxon in that the supposedly diagnostic four ‘pores’ are often either incompletely or not developed; this is apparent from both Naumova’s and Teteriuk’s illustrations and also from the Spitsbergen speci- mens described below. These latter represent an interesting new Lower Carboniferous occurrence, but are insufficient basis for the seemingly necessary, comprehensive re- appraisal of the genus, the most significant feature of which appears to be constantly quadrangular shape. Affinity. The angiospermous attribution (Naumova 1939, 1950; Teteriuk 1956, 1958) of Tetraporina has been regarded doubtfully by many subsequent authors (Staplin 1960, p. 6; Scott, Barghoorn, and Leopold 1960, p. 287; Hughes 1961, p. 89). Certainly the brief descriptions and line drawings of the Russian forms are inadequate for a critical assessment of botanical affinity. The possible algal affinity of the genus was discussed recently by Scott et al. (1960, p. 287), who noted its close morphological similarity with species of the unicellular green alga Tetraedron. Valuable support in this connexion is apparent from a paper by Churchill (1960), who figured a number of Cainozoic and living unicellular algae and aplanospores; of his illustrations, fig. 1, nos. 3, 4, 6, 8, 11, 12, and 13 show striking superficial resemblance to Tetraporina. Moreover, Dr. Churchill G. PLAYFORD: LOWER CARBONIFEROUS MICROFLORAS 659 has kindly examined the specimens described below and he considers that there is little doubt of their algal affinity. Tetraporina incrassata Naumova 1950 Plate 95, figs. 12, 13 Description of specimens. Spores alete; outline quadrangular with distinctly concave sides and rounded corners. Exine scabrate to almost smooth, generally about 2 /x thick; locally ± conspicuously thickened at corners, which may occasionally show aperture- like perforations. Dimensions (12 specimens). Diagonal length 46-70 /x (mean 60 f). Previous records. From the Lower Carboniferous of the Moscow Basin (Naumova 1950). Tetraporina glabra Naumova 1950 Plate 95, fig. 1 1 Description of specimens. Spores alete; outline quadrangular with concave sides and rounded angles. Exine uniformly thick (3 f), laevigate. In the figured specimen one minute perforation is present in the vicinity of each corner; the other specimens en- countered appear non-perforate. Dimensions (3 specimens). Diagonal length 50-54 /x. Previous records. From Lower Carboniferous deposits of the Moscow Basin (Naumova 1950). Tetraporina horologia (Staplin) comb. nov. Plate 95, figs. 14, 15 1960 Azonotetraporina? horologia Staplin p. 6; pi. 1, figs. 4, 6. Description of specimens. Spores alete; outline quadrangular with concave to almost straight sides and rounded corners. Exine thin, hence readily folded and distorted; surface finely granulate to slightly roughened. Apertures rarely evident, but often simulated by arcuate folds at the corners. Dimensions (14 specimens). Diagonal length 44-71 /x (mean 56 /x). Remarks. As discussed above, Azonotetraporina Teteriuk is not a valid genus and in any case appears to be a misconceived subdivision of Tetraporina Naumova. Accord- ingly Staplin’s species, which was questionably referred to Azonotetraporina , is here transferred to Tetraporina. Comparison. Tetraporina glabra Naumova 1950 (pi. 1, figs. 5, 28) is thicker-walled, but otherwise similar to T. horologia (Staplin) comb. nov. Previous records. From the Golata formation (Upper Mississippian) of Alberta, Canada (Staplin 1960). 660 PALAEONTOLOGY, VOLUME 5 MICROFLORAL ASSEMBLAGES AND STR ATIGR APHIC AL APPLICATIONS The primary object of this section is to assess the stratigraphical significance of the microfloral elements, described above, of the Lower Carboniferous succession of Spits- bergen. It will be shown below that two distinct, successive, microfloral suites (assem- blages) are distinguishable, each characterized by a number of distinctive microspore species of restricted stratigraphical ranges and hence of considerable correlative value both within and outside Spitsbergen. Evidence will be adduced as to the age of these assem- blages, with reference to the standard European stage subdivisions of the Carboniferous, on the admittedly indirect basis of Russian and North American microfloral parallelism. As noted previously, the microfloras examined in the present study have been recovered from a wide variety of lithologies (especially clastic rock types), and are thus probably fairly representative of the overall contemporary flora. Collecting has been insufficiently detailed, however, to permit palaeoecological inferences based upon quantitative/ qualitative studies of the microflora observed throughout a limited stratigraphical suc- cession (cf. Neves 1958). Delineation of microfloral assemblages Detailed study of microfloras contained in samples collected from the three suc- cessions, at Birger Johnsonfjellet, Triungen, and Citadellet (see text-fig. 2), has given an overall picture, as comprehensive as sampling intervals permit, of the microfloral succession in the Spitsbergen Lower Carboniferous. Tables 1 and 2 list all the micro- spore species present in the samples from these localities; in the preparations of most samples, abundance and sufficiently good preservation of the microfloral elements has permitted representation on a quantitative basis, resulting from a count of 250 specimens per sample. It will be evident from these Tables that, whilst many species are ubiquitous, a fairly large number possess restricted vertical distribution. A more or less uniform microfloral suite occurs in samples from the lower parts of the Birger Johnsonfjellet and Triungen sections and in the entire collected Citadellet section (see Table 1). This dis- tinctive suite is here conveniently designated as the Rarituberculatus Assemblage. The EXPLANATION OF PLATE 95 All figures x 500, and from unretouched negatives. Figs. 1-3. Retialetes radforthii Staplin 1960. 1, Preparation PI 55/7, 36 0 106-0 (L.1246). 2, Showing longitudinal rupture; preparation P155/13, 33-9 105-2 (L.1247). 3, Preparation PI 55/10, 36-9 103-3 (L.1248). Figs. 4-6. Spinozonotriletes balteatus sp. nov. 4, Holotype; distal surface. 5, Tetrad; preparation P149A/1, 26-4 100-4 (L. 1243). 6, Proximal surface; preparation P145B/1, 17-9 95-6 (L.1242). Figs. 7-9. Radialetes costatus gen. et sp. nov. 7, Preparation PI 63/ 1 , 38-7 107-9 (L.1250). 8, Prepara- tion P145B/7, 35-2 106-0 (L.1251). 9, Holotype. Fig. 10. Alatisporites tessellatus Staplin 1960. Proximal surface; preparation P163/2, 40-4 113-5 (L. 1245). Fig. 11. Tetraporina glabra Naumova 1950. Preparation P145B/5, 35-5 104-2 (L.1255). Figs. 12, 13. Tetraporina incrassata Naumova 1950. 12, Preparation P139/4, 30-1 103-6 ( L. 1 253). 13, Preparation P145A/1, 44-7 102-6 (L.1254). Figs. 14, 15. Tetraporina horologia (Staplin) comb. nov. 14, Preparation PI 8 1/3, 32- 1 105-5 (L.1256). 15, Preparation P202/3, 31-9 97-7 (L.1257). Palaeontology, Vol. 5 PLATE 95 PLAYFORD, Lower Carboniferous microspores G. PLAYFORD: LOWER CARBONIFEROUS MICROFLORAS 661 mic ros po re B 1 RGER J OHNSONFJ ELL ET T Rl UNGE N CITADELLET species G1086 G1087 G1088 G1089 G1090 G1091 G1473 G1472 G1445 G1446 G1448 G1450 G1451 G1453 Chaetosphaerites pollenisimilia X Leiotriletes inerraia X 2.0 0.4 X X 3.6 1.2 2.4 4.4 1.6 4.4 5.2 2.4 4.4 L. subintortus var. rotundatua x 1.6 2.8 X X X X X 1. 2 2.0 2.0 1.6 4. 4 L. omatua X X 0. 4 X 1.6 x 0.8 0.4 0.8 1.6 0.8 1.6 L. microgranulatua X X 0.8 0.8 4.0 Punctatiaporitea glaber X 3.6 2.8 2.8 X 3.6 0.4 1.6 5.6 6.4 7.2 10.0 5.6 8.8 P. parvivermiculatua X X 2.0 1.6 X 0. 4 0. 4 x 2.0 0.8 0.8 P. labiatus 0. 4 X X X 0. 4 1.6 P. paeudobeaua 0.4 Calamospora microrugoaa X 2.4 2.0 1. 2 0.8 1.2 0.8 3.2 2.8 3.6 3.2 4.0 2.8 Phyllothecotriletes rigidua X X 1.2 0.8 X 2.8 2.8 Granulatiaporitea planiueculua X Cyclogranisporites laaiua X 2.4 0. 4 0.4 0.4 3.2 1.6 5.6 5. 2 2.8 2.4 C. flexuoaua 0.8 X 0.8 0.8 1.6 0.8 1. 2 Verrucoaiaporitea gobbettii X X X 0.4 1. 2 1.2 1.2 Lophotriletea coniferus X 4.4 1. 2 X 0.4 X X Apiculatiaporia raacrurua 0.4 3-2 0.4 0.4 0.8 Acanthotriletea multiaetua X 0.8 2. 4 11. 2 12.0 6.4 5.2 4.8 A. mirua X X X Convolutispora tuberculata 3.6 X 0. 4 0.8 0.8 1.6 1. 2 4.4 2.8 1.6 C. vermiformia x 4.8 0.4 2.0 6.8 0.4 3.6 3.2 1.6 1.6 0.8 0. 4 G. harlandii 3.2 0.8 2.0 X 1. 2 2.8 0.4 0.8 0.4 0.4 1.6 0.4 G. craaaa 0.4 0.4 0. 4 X X 0.8 X Microreticulatiaporitea lunatua 0.8 0.4 0.8 0.4 1. 6 2.8 2.0 0.8 Dictyotriletea caperatua X 0. 4 2.8 0.8 1.2 0.8 Reticulatiaporitea cancellatua 0.8 4.8 X 0.8 12.8 0.8 0.8 x 2.8 1.2 R. planus 0. 4 0.4 0.8 X X 0.4 0.8 0.4 X Perotrilites perinatus 2.0 X 1. 2 X 0. 4 0.4 X 1. 2 1.6 1.2 1. 2 0.4 0.4 P. magnus X 4.4 0. 4 X 0.8 0.4 X 1.2 X X 0.8 Triquitrites batillatus X 1.6 Tripartites inciaotrilobua 19. 2 X 2.8 2.8 0. 4 1. 2 2.8 7.6 Stenozonotriletea stenozonalis X x X S. facilia var. praecrasaua X 0.4 X x X 2.4 0.8 0.4 S. simplex X 2.0 3.2 X 1.6 0.8 1.6 S. inauctus X X X X X S. clarus X 0.8 0.4 0.8 0.4 0.4 S. perforatus X X 2.0 0.8 2.0 S. cf. spetcandua * X X X X Murospora intorta X X X M. conduplicata 2.0 3.6 1.6 0.8 X 0. 4 4. 4 X 1.6 1.6 M. sublobata X X 0.8 2.0 0.8 0.8 Anulatiaporites anulatua X 6.4 10.8 X 5. 2 2.4 3.2 2.4 A. labiatus 3.2 3.2 x 1.6 3.6 8.0 18.8 8.4 2.8 0. 4 5.2 0.8 A. orbiculatus X X X A. canaliculatus 0.8 X X X X 0.8 0. 4 1.2 0.8 0.8 x X Densosporitea dentatus 2.4 X 36.0 30.4 1.6 4.0 4.8 6.4 4.8 D. intermedius 2.4 2.8 X 3.2 0.4 0.8 1. 2 5.0 6. 4 D. variabilis D. striatiferus 21. 2 X 1.2 x 0.4 X 3.2 D. spitsbergensis 2.8 2.8 4.0 X 8.0 1.6 3.6 3.6 5.6 P. variomarginatus 8. 4 16.8 X 4.8 10.8 1. 2 10.0 6.4 16.8 10.8 Labiadensites fimbriatus 1. 2 0.4 X 0.4 Knoxisporites cinctus X X 1.6 X 0.8 X X K. margarethae 0.8 0.8 0.8 0.4 X 2.8 6.0 X X X X K. literatus 1.6 1.6 0.4 0.4 X 0. 4 0.4 0.8 K. heaeratus X X 0.4 0.8 0.8 0.8 Cristatisporites echinatus X X X X Lophozonotriletes rarituberculatus X 7.2 1.2 2.8 X 0.8 0.4 X 4. 4 2.8 0.8 0.8 0.8 0.8 L. dentatus 1. 2 X 1.6 X L. variverrucatus X 0. 4 1. 2 2. 4 X 0. 4 0. 4 X Tholisporites foveolatus 3.6 43.6 2. 4 14.8 26.0 18.4 22.0 2.0 0.8 0.8 Endosporites micromanifestus 0.4 0. 4 X X 0.8 0.8 4. 4 5.2 1. 2 2.4 Velosporites echinatus 0.4 0. 4 0.8 0.4 6.0 X X 0.8 0. 4 x 0. 4 x V. microreticulatus 0. 4 X X Spinozonotriletea uncatus X 0. 4 1. 2 X X 1. 2 0. 4 1. 2 Alntisporites tessellatua 0.4 X Radialetes costatua 0.4 X X X X X 0.8 0.4 X 0.4 Tetraporina incrasaata T. horologia X - table 1 . Microspore distribution in samples from the Citadellet succession and from the lower parts of the sections exposed at Birger Johnsonfjellet and Triungen. In most samples, constituent species are recorded as percentages, which are based upon individual counts of 250 specimens. Indeterminable specimens in each case comprise the percentage complementary to that of specifically determinable specimens. ‘ x ’ indicates observed presence in a particular sample, but not in actual count. Relatively sparse and poorly preserved spores were recovered from samples G1086 and G1090, and hence neither was considered suitable for quantitative specific estimation. Correction : for Densosporites intermedius read D. diatretus (see p. 623). micros po re species BIRGER JOHNSONFJELLET T R UNGEN G1092 G1093 G1095 G1096 G1098 G1099 G1101 G1102 G1471 G1470 G1469 G1468 G1467 G1466 G1465 Chaetosphaerites pollenisimilis 0.4 1.2 2.4 1.2 X 0.4 0.4 X 3.6 Leiotriletes inermis 1.6 0.8 1.6 2.4 2.0 X 0.8 0.8 x X 1.6 0.4 L. subintortus var. rotundatus 0. 4 X 1.6 1. 2 X X 1.6 X 0.4 X 0.4 0.4 L. omatus X 0.4 X 0.4 X 0.4 L. curiosus 0.8 X Punctatisporites glaber 0.8 0.4 1.2 3.2 1.2 X 2.4 X 5.6 X 1.2 2.0 0.8 P. parvivermiculatus 0. 4 P. pseudobesus 1. 6 4.8 2.0 P. stabilis 1. 2 0. 4 X 0.4 X 2.0 Calamospora microrugosa 0.8 0.4 0.8 2.4 0.4 X 0.4 X 2.8 2.0 2.4 1.2 Phyllothecotriletes rigidus * x x X X X X 0.4 X 0.4 X Waltzispora lobophora X X X X 0.4 W. albertensis X 0.8 X 6.4 W. sagittata X Cyclogranisporites lasius X X 0.8 X 5.2 0.8 X C. flexuosus X 0. 4 X X 0.4 X Verrucosisporites eximius X X X o3T 0. 4 X Anapiculatisporites concinnus 0.4 1.2 0.8 8.8 A. serratus 1. 2 X 2.4 Acanthotriletes raultisetus 0.4 Hystricosporites sp. X Convolutispora tuberculata X 2.0 X X X 0.4 X 36.0 2. 4 X C. clavata 0.8 X C. harlandii 2.0 0. 4 0.8 C. crassa X X C. labiata 0. 4 C. usitata 1. 2 0. 4 X 0.8 X X Microreticulatisporites lunatus x 0.4 X X X Reticulatisporites rudis X X R. cancellatus 4. 4 2.0 2.8 2.4 0.4 X 2.0 0.8 X X x 0.4 R. variolatus 1. 6 0.8 X X 0.4 x X X X R. peltatus X 1.6 X X X X 0.4 X X R. ? sp. X Foveosporites insculptus 0.4 0.4 X X X 4.4 X 0.8 4.0 X Perotrilites perinatus X X X P. magnus X 0.4 0.8 X X Triquitrites trivalvis 0.8 X X 0.8 0.4 T. batillatus 5.6 1.2 0.8 0.4 X 0.4 0.4 X Tripartites incisotrilobU9 1.2 0.4 2.8 X X 0.8 0.8 1. 2 0.8 1.2 T. complanatus X X X 0.4 Stenozonotriletes clarus X X X 0. 4 0.4 S. facilis var. praecrassus 0. 4 X X X S. perforatus 0.4 S. cf. spetcandus X X Murospora intorta 0.8 0. 4 0.4 0.4 0.8 X X 0.8 X X X 0.8 M. aurita 12.8 24.8 4.8 4.4 28.0 x X 7.2 X 1. 2 0.4 0.4 5.2 X M. conduplicata X 0. 4 1. 2 0.4 X X X 0.4 X 0.4 X 0.8 0.4 2.0 X M. sublobata 0. 4 X 0.4 X X X X 0.4 X X 1. 2 X M. dupla X M. strigata x 0.4 M. tripulvinata X X M. friendii 2.0 X X X 0.4 0.4 0. 4 Anulatisporites anulatus 1. 2 0.8 4.8 2.0 0.4 X 0.4 X 2.0 1. 2 4.0 0.8 A. labiatus 1.6 0.4 0.4 X X X X 0.4 X 0.8 X X Densosporites bialatus 18. 4 1.6 0.8 X 1.2 X 0.8 0.8 1. 2 D. dentatus 3.2 2.0 12.0 2.0 4.0 X 4.0 X 8.4 X 0.8 . 12.4 1. 2 D. subcrenatus X X X X X X X 0.4 0.8 D. intermedius 3.6 6.8 4.2 1.2 0. 4 x 3.6 x 2.0 1.2 D. variabilis 26. 4 23.6 16.8 6.4 4.0 X 1.6 X 12.8 X 0.8 46.0 6.4 D. duplicatus 0.4 0.8 X X 0.4 X X 0.8 X X D. spitsbergensis 10.0 13.2 3.6 2.0 X 1.2 X 0.8 D. rarispinosus 0.8 4.4 X 2.4 D. aculeatus 2.4 X X X X 0.8 X 0.8 D. sp. X X Labiadensites fimbriatus 5.6 0.8 0.8 X 0.4 X X X X X 6.4 2.0 0.4 Knoxisporites cinctus 1.2 K. margarethae X K. literatus 6.4 11.2 2.4 X X X 0.8 X 0.4 0.4 Lycospora uber 2.0 56.8 43.2 X X 61. 2 X 5.6 X 2.4 2.4 32.4 Lophozonotriletes appendices X 0.4 X 0.4 1.6 Monilospora triungensis 0.4 M. dignata X 0.8 Potoniespores delicatus X 1.2 X 0.4 X 0.4 X Cirratriradites Solaris X X C. elegans X 0.8 X 0.4 Caraptozonotriletes velatus 2.4 0.4 2.0 X X 1.6 X 0.4 1. 2 X Diatomozonotriletes saetosus X 1. 6 X X 0.4 0.8 X D. hughesii X X X X 0.8 X 6.0 0.8 0.8 2. 4 D. trilinearis 4.0 4.4 0.8 0.4 D. rarus X X Endosporites micromanifestus x 0. 4 X X X X 0.4 X Remysporites albertensis X x Velosporites microreticulatus X Spinozonotriletes balteatus 13.6 X 21.6 0.8 2.8 Alatisporites tessellatus 0.4 X Retialetes radforthii X X Radialetes costatus 1. 2 0.4 X x 0. 4 X X Tetraporina incrassata X T. glabra X T. horologia X 0.4 X table 2. Microspore distribution in Birger Johnsonfjellet and Triungen samples succeeding those documented in Table 1. In most samples, constituent species are recorded as percentages, which are based upon individual counts of 250 specimens. Indeterminable specimens in each case comprise the percentage complementary to that of specifically determinable specimens. ‘ X ’ indicates observed presence in a particular sample, but not in actual count. Counting was precluded in samples G1099, G1101, G1471, G1469, and G1465, owing to sparse occurrence and/or poor preservation of the recovered spores. Correction : for Densosporites intermedius read D. diatretus (see p. 623). G. PLAYFORD: LOWER CARBONIFEROUS MICROFLORAS 663 younger microfloral suite, termed the Aurita Assemblage, is present in samples from Birger Johnsonfjellet and Triungen, immediately succeeding those documented in Table 1. It includes many species unknown from the Rarituberculatus Assemblage and lacks a considerable number characteristic of the latter. The detailed microfloral analysis of the samples from Birger Johnsonfjellet and Triungen which contain the Aurita Assemblage is presented in Table 2. This microfloral subdivision is not intended to suggest finality, as it is recognized that subsequent work on more detailed collections may well provide a more precise microflorally based zonation. In the Birger Johnsonfjellet section, the change in microspore content occurs strati- graphically between samples G1091 and G1092, at respectively 128 metres and 138 metres above base. At Triungen the change occurs between samples G1472 and G1471, at respective heights above base of 100 metres and 132 metres. The apparent abruptness of this ‘change’ would possibly be in fact reduced to a transition if intermediate samples from both sections were available. It is important to note, however, that none of the samples from other localities contains evidence of a mixture of the diagnostic representa- tives of the two assemblages discussed below. The Rarituberculatus Assemblage. The older assemblage, which is named from the most consistently occurring species (see Table 1 ), is characterized diagnostically by the follow- ing microspore species: Lophozonotriletes rarituberculatus (Luber) Kedo 1957 Verrucosisporites gobbettii sp. nov. Lophotriletes coniferus Hughes and Playford 1961 Convolutispora vermiformis Hughes and Playford 1961 Dictyotriletes caperatus sp. nov. Reticulatisporites planus Hughes and Playford 1961 Stenozonotriletes induct us Ishchenko 1956 Anulatisporites canaliculatus sp. nov. Densosporites striatiferus Hughes and Playford 1961 Densosporites variomarginatus sp. nov. Knoxisporites hederatus (Ishchenko) comb. nov. Cristatisporites echinatus sp. nov. Lophozonotriletes dent at us Hughes and Playford 1961 Lophozonotriletes variverrucatus sp. nov. Tholisporites foveolatus Hughes and Playford 1961 Velosporites echinatus Hughes and Playford 1961 Spinozonotriletes uncatus Hacquebard 1957 Other species apparently exclusive to the older assemblage, but of less common occurrence, are: Punctatisporites labiatus sp. nov., Leiotriletes microgranulatus sp. nov., Acanthotriletes mints Ishchenko 1956, and Stenozonotriletes stenozonalis (Waltz) Ishchenko 1958. The following species are common but not diagnostic components of the Rari- tuberculatus Assemblage: Cyclogranisporites flexuosus sp. nov., Convolutispora tuber- culata (Waltz) Hoffmeister, Staplin, and Malloy 1955, Reticulatisporites cancellatus (Waltz) comb, nov., Perotrilites perinatus Hughes and Playford 1961, P. magnus Hughes and Playford 1961, Tripartites incisotrilobus (Naumova) Potonie and Kremp 1956, Stenozonotriletes clarus Ishchenko 1958, Murospora conduplicata (Andrejeva) comb, nov., M. sublobata (Waltz) comb, nov., Anulatisporites anulatus (Loose) Potonie and Kremp 1954, A. labiatus Hughes and Playford 1961, Densosporites dentatus (Waltz) 664 PALAEONTOLOGY, VOLUME 5 Potonie and Kremp 1956, D. diatretus nom. nov., D. spitsbergensis sp. nov., Knoxisporites cinctus (Waltz) Butterworth and Williams 1958, K. margarethae Hughes and Playford 1961, K. literatus (Waltz) comb, nov., Endosporites micromanifestus Hacquebard 1957, and Radialetes costatus gen. et sp. nov. The Aurita Assemblage. From a comparison of Tables 1 and 2 it is evident that this assemblage comprises an even more diverse microflora than that represented by the Rarituberculatus Assemblage. In particular, zonate forms ( Cirratriradites , Campto- zonotriletes, Potoniespores, Diatomozonotriletes ) appear significantly; the older assem- blage appears to be entirely devoid of zonate ( s . str.) spores. Other striking generic introductions are Lycospora, Anapiculatisporites, Waltzispora, Monilospora, Foveo- sporites, Remysporites, and Retialetes. Furthermore, the genera Reticulatisporites, Convolutispora, Densosporites, and Murospora are represented prolifically by numerous species in this younger assemblage. Especially significant is the total absence of Lopho- zonotriletes rarituberculatus (Luber), the ‘index’ species of the older microfloral suite. The following microspore species are considered diagnostic components of the Aurita Assemblage, and have not been observed in the older assemblage: Murospora aurita (Waltz) comb, nov., emend. Waltzispora lobophora (Waltz) Staplin 1960 Waltzispora albert ensis Staplin 1960 Waltzispora sagittata sp. nov. Verrucosisporites eximius sp. nov. Anapiculatisporites concinnus sp. nov. Reticulatisporites variolatus sp. nov. Reticulatisporites peltatus sp. nov. Foveosporites insculptus sp. nov. Triquitrites trivalvis (Waltz) Potonie and Kremp 1956 Murospora friendii sp. nov. Densosporites bialatus (Waltz) Potonie and Kremp 1956 Densosporites subcrenatus (Waltz) Potonie and Kremp 1956 Densosporites duplicatus (Naumova) Potonie and Kremp 1956 Densosporites rarispinosus sp. nov. Densosporites aculeatus sp. nov. Lycospora uber (Hoffmeister, Staplin, and Malloy) Staplin 1960 Lophozonotriletes appendices (Hacquebard and Barss) comb. nov. Potoniespores delicatus sp. nov. Cirratriradites elegans (Waltz) Potonie and Kremp 1956 Camptozonotriletes velatus (Waltz) comb. nov. Diatomozonotriletes saetosus (Hacquebard and Barss) Hughes and Playford 1961 Diatomozonotriletes hughesii sp. nov. Spinozonotriletes bait eat us sp. nov. The Assemblage name is based upon the species Murospora aurita (Waltz), which is almost invariably present, often as the predominating species (see Table 2). Other species which are much rarer than those of the foregoing list, but which never- theless appear similarly restricted to the younger assemblage, are as follows : Leiotriletes curiosus sp. nov., Anapiculatisporites serratus sp. nov., Convolutispora clavat a (Ishchenko) Hughes and Playford 1961, Reticulatisporites rudis Staplin 1960, Reticulatisporites? sp., Tripartites complanatus Staplin 1960, Murospora dupla (Ishchenko) comb, nov., M. strigata (Waltz) comb, nov., M. tripulvinata Staplin 1960, Monilospora triungensis sp. nov., M. dignat a sp. nov., Cirratriradites Solaris Hacquebard and Barss 1957, Diatomo- G. PLAYFORD: LOWER CARBONIFEROUS MICROFLORAS 665 zonotriletes trilinearis sp. nov., D. rarus sp. nov., Remysporites albertensis Staplin 1960, and Retialetes radforthii Staplin 1960. The following species, which are also components of the Rarituberculatus Assemblage, are often present in significant proportions: Chaetosphaerites pollenisimilis (Horst) Butterworth and Williams 1958, Convolutispora tuberculata (Waltz) Hoffmeister, Staplin, and Malloy 1955, Retieulatisporites cancellatus (Waltz) comb, nov., Triquitrites batillatus Hughes and Playford 1961, Tripartites incisotrilobus (Naumova) Potonie and Kremp 1956, Mwospora intorta (Waltz) comb, nov., M. conduplicata (Andrejeva) comb, nov., M. sublobata (Waltz) comb, nov., Anulatisporites anulatus (Loose) Potonie and Kremp 1954, A. labiatus Hughes and Playford 1961, Densosporites dentatus (Waltz) Potonie and Kremp 1956, D. diatretus nom. nov., D. variabilis (Waltz) Potonie and Kremp 1956, D. Spitsbergen sis sp. nov., Labiadensites fimbriatus (Waltz) Hacquebard and Barss 1957, Knoxisporites literatus (Waltz) comb, nov., Endosporites micromanifestus Hacquebard 1957, and Radialetes costatus gen. et sp. nov. The Birger Johnsonfjellet and Triungen samples, from which the Aurita Assemblage has been recovered, are lithologically more diverse than those from which the older assemblage has been studied. It seems relevant, therefore, to consider the general relationships observed between rock-type and contained microfloral elements, although, as noted previously, detailed palaeoecological inferences are not possible. For this pur- pose a series of histograms (text -fig. 12) has been constructed to represent the relative proportions of common microfloral constituents observed in five lithological types, all of which contain the Aurita Assemblage. The microflora of the dull coal (E363) and of the highly carbonaceous (coaly) shale (R38) are notably restricted in comparison with those of the other sediments represented on text-fig. 12. In E363 the predominating forms are species of Densosporites , and Retieulatisporites cancellatus (Waltz) is also an important constituent. The microflora of R38 is marked by an extremely high per- centage of Murospora aurita (Waltz). In the fine-grained sandstone (Gl 102) and the two carbonaceous shales (G1098, G1466) the microfloras exhibit considerable diversity, with Lycospora uber (Hoffmeister, Staplin, and Malloy) as the most abundant component. By contrast this species is comparatively rare in E363 and R38. These spore associations are probably representative of a more or less contemporary flora as preserved in sedi- ments which accumulated in different ecological situations; possible botanical implica- tions will be discussed subsequently in this paper. A summary compilation of the species characteristic of the two microfloral assem- blages is presented on Table 5. Age of the microfloral assemblages The Rarituberculatus Assemblage. The ‘index’ species of this assemblage, Lopho- zonotriletes rarituberculatus (Luber), is a characteristic constituent of Russian strata of Tournaisian age (Luber and Waltz 1941; Ishchenko 1956; Kedo 1957, 1958, 1959; Byvsheva 1957, 1960). It has not been recorded from Visean or younger rocks, but was reported by Luber and Waltz (1941) from allegedly Upper Devonian sediments of the Timan Peninsula and Kizel region. However, more recent Russian work (as cited above) seems to suggest that L. rarituberculatus is an exclusively Tournaisian form. Another significant species is Spinozonotriletes uncatus Hacquebard, which has been described from the lowermost Mississippian of Canada. Its possible Russian equivalent. 666 PALAEONTOLOGY, VOLUME 5 Acanthozonotriletes senticosus Ishchenko, is confined to Tournaisian deposits of the western Donetz Basin. Two other species described by Ishchenko (1956), Stenozono- triletes inductus and Acanthotriletes mirus, have similar vertical restriction. Convolutispora venniformis Hughes and Playford occurs in Canadian strata of lowest Mississippian and of probable Upper Devonian age. °/ 8 0-1 sandstone G I i o 2 8 0n shale G I O 98 8 0-| shale G I 4 6 6 1. WALTZISPORA 2. A N A P I C U L A T I S P O R I T E S 3. RETICULATISPORITE5 CANCELLAT 4. TRIPARTITES INCISOTRILOBUS 5. MUROSPORA AURITA 6. DENSOSPORITES 7. LYCOSPORA UBER 8. ALL OTHERS U S text-fig. 12. Histograms showing microspores present in different rock-types containing the Aurita Assemblage. Numerous other components of the Rarituberculatus Assemblage, most of which are also present in the younger assemblage, are unknown from pre-Tournaisian strata. These are: Chaetosphaerites pollenisimilis (Horst), Acanthotriletes multisetus (Luber), Microreticulatisporites lunatus Knox, Tripartites incisotrilobus (Naumova), Steno- zonotriletes facilis Ishchenko var. praecrassus Ishchenko, Murospora intorta (Waltz), M. conduplicata (Andrejeva), M. sublobata (Waltz), Zonotriletes macrodiscus Waltz (probable Russian equivalent of Anulatisporites labiatus Hughes and Playford), Anulati- G. PLAYFORD: LOWER CARBONIFEROUS MICROFLORAS 667 sporites orbiculatus (Waltz), Densosporites dent atus (Waltz), D. diatretus, D. variabilis (Waltz), Labiadensites fimbriatus (Waltz), Knoxisporites cinctus (Waltz), K. hederatus (Ishchenko), and Endosporites micromanifest us Hacquebard. From the above evidence it is concluded that the Rarituberculatus Assemblage is of Tournaisian age. The Aurita Assemblage. The younger assemblage is marked by the absence of the characteristic Tournaisian species cited above and especially notable is the sudden dis- appearance of Lophozonotri/etes rarituberculatus (Luber). Murospora aurita (Waltz), the ‘index’ species of the Aurita Assemblage, was described initially (Luber and Waltz 1938, 1941) from Russian strata, the age of which was not specified more precisely than ‘Lower Carboniferous’. Subsequent investigations (Hacquebard and Barss 1957; Staplin 1960) indicate its presence in Canadian deposits of Upper Mississippian age. These latter occurrences, together with evidence from the present study of the complete absence of M. aurita in the older assemblage, suggest strongly that the species is post-Tournaisian. It is noteworthy also that M. aurita is un- known in rocks definitely assignable to the Namurian stage. Numerous other Russian, Canadian, and British species are important constituents of this assemblage. Convolutispora elavata (Ishchenko), Murospora dtip/a (Ishchenko), M. strigata (Waltz), and Triquit rites trivalvis (Waltz) have been recorded as exclusively Visean species in the U.S.S.R., although the latter species is known also from Namur- ian A coals of Scotland (Butterworth and Williams 1958). Waltzispora sagittata sp. nov. occurs in the Scottish Visean (Love 1960). The following species are unknown from Namurian or younger strata of the U.S.S.R. . Reticulatisporites caneellatus (Waltz), Stenozonotriletes clarus Ishchenko, Murospora conduplieata (Andrejeva), Densosporites dentatus (Waltz), Labiadensites fimbriatus (Waltz), and Camptozonotriletes velatus (Waltz). Densosporites subcrenatus (Waltz), Cirratriradites elegans (Waltz), and Diatomo- zonotriletes saetosus (Hacquebard and Barss) are apparently confined in Russia to rocks of Visean and Namurian age. Lycospora uber (Hoffmeister, Staplin, and Malloy), which is often an extremely abundant constituent of the assemblage, appears from previous records to range from lowest Visean to at least Westphalian A. The following species have been reported hitherto from strata ranging in age from Tournaisian to Namurian; Convolutispora tuberculata (Waltz), Tripartites incisotrilobus (Naumova), Stenozonotriletes facilis Ishchenko var. praecrassus Ishchenko, Denso- sporites intermedius (Waltz), D. variabilis (Waltz), Knoxisporites literatus (Waltz), and Endosporites micromanifestus Hacquebard. Densosporites bialatus (Waltz) is also known to be similarly long-ranging, but appears to be especially abundant in Russian strata of Visean-Namurian age. A number of species, confined to the Aurita Assemblage, are common to the coal microflora described by Hacquebard and Barss (1957), which is probably equivalent in age to the Middle Chester series of the United States. These comprise: Waltzispora albertensis Staplin, which is present also in the Russian Lower Carboniferous (Reinsch 1884) and was formally described by Staplin (1960); Cirratriradites Solaris Hacquebard and Barss, also recorded by Staplin (1960); Densosporites duplicatus (Naumova), 668 PALAEONTOLOGY, VOLUME 5 initially reported by Luber and Waltz (1938) from the Russian Lower Carboniferous; and Lophozonotriletes appendices (Hacquebard and Barss). The microflora described by Staplin (1960) is from the Golata formation of Canada, which is equivalent in age to the Lower Chester series of the United States and is thus probably slightly older than the coal investigated by Hacquebard and Barss (1957). The following species, all described for the first time by Staplin (1960), are restricted in Spitsbergen to the Aurita Assemblage: Reticulatisporites rudis , Tripartites complanatus, Murospora tripulvinata, Remysporites albertensis, and Retialetes radforthii. In particular, the latter species appears to be confined at Birger Johnsonfjellet and Triungen to the stratigraphically highest beds containing the younger assemblage. Very little obvious similarity exists between the Aurita Assemblage and the Namurian microfloras described by Horst (1955), Dybova and Jachowicz (1957), Butterworth and Williams (1958), and Neves (1961). Indeed, the only species in common are those which are known from the work of other authors to occur also in strata of greater age, i.e. at least Visean. Furthermore, none of the definitely post-Visean Russian species, as docu- mented by Ishchenko (1956, 1958), is present in the assemblage. It is evident that the Aurita Assemblage conforms closely at specific level with micro- floras reported by numerous authors from Visean strata of the U.S.S.R. Significant correlation can also be made with Lower-Middle Chester microfloras of Canada. As noted previously in this paper, the European equivalence of the Chester series is some- what uncertain, but more recent goniatite and conodont studies suggest correlation of the lower part of the series with the Upper Visean rather than with the Namurian A. Collectively, the above evidence strongly indicates that the Aurita Assemblage is of Visean age, although a possible extension into the older Namurian is not precluded. Definite pronouncement in this latter respect must necessarily await more conclusive palaeontological evidence concerning the European equivalence of the Chester seiies, coupled with further palynological investigation of the North American Mississippian, the microfloras of which are as yet only sparsely known (see text-fig. 4). As discussed previously, the two microfloral assemblages are represented successively in the sections at Birger Johnsonfjellet and Triungen. Thus the Billefjorden Sandstones as developed at these localities incorporate strata ranging in age from Tournaisian to Visean, possibly to lowest Namurian. Certainly the presence (in the stratigraphically highest beds) of Retialetes radforthii , together with a number of other forms described by Staplin (1960) and Hacquebard and Barss (1957), seems to indicate an upper age limit of either topmost Visean or alternatively lowest Namurian. Samples from the Citadellet succession contain exclusively the Rarituberculatus Assemblage, hence indicating a Tournaisian age. However, the uppermost part of this section has not been sampled (see text-fig. 2) and it is possible therefore that beds of Visean age are represented at Citadellet. In situ samples were unobtainable from basal Billefjorden Sandstones of the three reference successions; thus the precise age of the lowermost part of the series at Birger Johnsonfjellet, Triungen, and Citadellet is unknown. Correlation within Svalbard The microfloral assemblages delineated above have been observed in preparations of samples from various other localities in Vestspitsbergen and from Nordkapp, Bjornoya. G . PLAYFORD: LOWER CARBONIFEROUS MICROFLORAS 669 Vestspitsbergen 1. Citadellet. Samples B685 (studied earlier by Hughes and Playford 1961) and B687 both contain prolific microfloras representative of the Rarituberculatus Assemblage, and as such are conformable with the other Citadellet samples recorded palynologically in Table 1. Age — Tournaisian. 2. Triungen. Sample G1461 contains an abundant and well-preserved microflora which is typical of the Aurita Assemblage. In parti- cular, the presence of the rare forms Reticula- tisporites? sp. and Retialetes radforthii suggests a similar horizon to that of sample G1466 of the known Triungen succession. Age — Upper Visean, or possibly lowermost Namurian. 3. Ebbadalen ( north side). Sample B706 yielded a fairly well-preserved microflora including the following diagnostic representa- tives of the younger assemblage: Murospora aurita , Wa/tzispora albertensis, Reticulatis- porites pelt at us. Densosporites bialatus, Lyco- spora uber, Camptozonotriletes velatus, Diatomozonotriletes saetosus, &c. Age — Visean. Sample W860 contains a somewhat poorly preserved microflora recognizably con- formable with the Aurita Assemblage. Significant species present include Murospora aurita, Convolutispora clavata, Reticulatisporites peltatus, Densosporites bialatus, Lycospora uber, Diatomozonotriletes saetosus, and Camptozonotriletes velatus. The additional presence of Convolutispora harlandii suggests correlation with a horizon Thus the rocks exposed at these localities (listed below) may be correlated with the palynologically documented successions at Birger Johnsonfjellet, Triungen, and Cita- dellet. Two comprehensive check lists (Tables 3 and 4) record the microspore species present in samples from localities other than those of the three successions. Table 3 incor- porates samples containing the Raritubercula- tus Assemblage, whilst the younger assemblage is represented (in a relatively large number of samples) in Table 4. Citation is made below of some of the more stratigraphically significant constituent species of each sample which, in containing one or other of the microfloral assemblages, is re- ferable implicitly to appropriate portions of the reference successions. The localities are shown on text-fig. 1 ; data on their stratigraphy have already been presented. LOCALITY A B SAMPLE NO. B 6 85 B 6 8 7 B 680 Leiotriletes inermis X X X L. subintortus var. rotundatus x X L. ornatus X X L. microgranulatus X X Punctatisporites glaber X X X P. parvivermiculatus X P. labiatus X Calamo9pora microrugosa X X X Phyllothecotriletes rigidus X Cyclogranisporites lasius X C. flexuosus X Verrucosi9porites gobbettii X X Lophotriletes coniferus X X Acanthotriletes multisetus X A. rairus X Convolutispora vermiforrais X X X C. harlandii X Microreticulatisporites lunatus X X Dictyotriletes caperatus X X Reticulatisporites cancellatus X X R. planus X X Perotrilites perinatus X X P. raagnus X X Tripartites incisotrilobue X Stenozonotriletes stenozonalis X S. inductus X S. clarus x X S. perforatus X X S. cf. spetcandus X Murospora conduplicata X X Anulati9porites anulatus X X A. labiatus X X X A. orbiculatus X A. canaliculatus X X Densosporites dentatus X X D. intermedius X X D. variabilis X D. striatiferus x D. variomarginatus X X Labiadensites fimbriatus X Knoxisporites cinctus X K. margarethae X X X Lophozonotriletes rarituberculatus X X X L. dentatus X X L. variverrucatus X X X Tholisporites foveolatus X X Endosporites microraanifestus X X Velosporites echinatus X X X Spinozonotriletes uncatus X Radialetes costatus X table 3. Check list of microspore species, representative of the Rarituberculatus Assem- blage, present in samples other than those documented in Table 1. Locality index — a, Citadellet; b, Odellf jellet. Correction: for Densosporites intermedins read D. diatretus (see p. 623). 670 PALAEONTOLOGY, VOLUME 5 comparable with that of G1095 in the Birger Johnsonfjellet succession. Age — Visean. Both these samples are from near the base of the Billefjorden Sandstones, suggesting that Culm sedimentation commenced at this particular locality relatively late in the Lower Carboniferous. 4. Ebbadalen ( south side). Samples B609 (recorded in Hughes and Playford 1961), B604, F531, F774, G332, G334, G366, and G382 are all from the same horizon, which is well above the base of the Culm. None yielded a well-preserved microflora. The follow- ing are some of the species, indicative of the Aurita Assemblage, which were observed in these complementary samples: Murospora aurita , Anapicuiatisporites concinnus, Reticulatisporites peltatus, Foveosporites insculptus, Triquitrites trivalvis, Tripartites complanatus, Murospora friend'd. Densosporites bialatus , D. duplicatus, D. rarispinosus, Lycospora uber, Potoniespores delicatus, Cirratriradites solan's, Diatomozonotr'detes saetosus, Remysporites albertensis, and Retialetes radforthii. Age — Upper Visean, or possibly lowermost Namurian. 5. Wordiekammen ( north side). The coal S59a (studied by Hughes and Playford 1961) contains a rather restricted microflora including such representatives of the younger assemblage as: Murospora aurita, Convolutispora clavata, Lycospora uber, and Spino- zonotriletes bah eat us. Age — Visean. 6. Adolfbukta ( north shore). A particularly well-preserved microflora, typical of the Aurita Assemblage, was obtained from sample W217. Species present include: Muro- spora aurita, Leiotriletes curiosus, Waltzispora lobophora, W. albertensis, Verrucosi- sporites eximius , Triquitrites trivalvis, Tripartites complanatus, Densosporites bialatus, D. duplicatus, Lycospora uber, Lophozonotriletes appendices, Cirratriradites Solaris, Diatomozonotriletes saetosus, D. hughesii, D. rarus, and Retialetes radforthii. Age — Upper Visean, or possibly lowermost Namurian. 7. De Geerfjellet. Samples G636 and T269, which are from the same outcrop and horizon, both yielded well-preserved microfloras characteristic of the Aurita Assemblage. Stratigraphically important species include: Murospora aurita, Waltzispora albertensis, W. sagittata, Anapicuiatisporites serratus, A. concinnus, Reticulatisporites? sp., R. rudis, R. peltatus, Tripartites complanatus, Triquitrites trivalvis, Murospora tripulvinata, Densosporites bialatus, D. duplicatus, Lycospora uber, Monilospora triungensis, Cirra- triradites Solaris, Diatomozonotriletes saetosus, D. hughesii, D. trilinearis, D. rarus, Spinozonotriletes balteatus, and Retialetes radforthii. Age — Upper Visean, or possibly lowermost Namurian. 8. Ragnarbreen. A somewhat restricted microflora was obtained from the coal R38 (see text-fig. 12). Constituent species include the following, all representative of the younger assemblage: Murospora aurita, Waltzispora albertensis, Reticulatisporites peltatus, Triquitrites trivalvis, Murospora friendii, Densosporites bialatus, Lycospora uber, Camptozonotriletes velatus, Diatomozonotriletes saetosus, & c. Age — Visean. 9. Anservika. The microfloras obtained from samples R5, F20, D120, G1283, G1280, G1278, and G1276 are specifically similar and, as they were collected from approxi- mately the same horizon, may be considered here collectively. The Aurita Assemblage is represented by such forms as Murospora aurita, Waltzispora albertensis, W. sagit- tata, Verrucosisporites eximius, Convolutispora clavata, Reticulatisporites variolatus, R. peltatus, Foveosporites insculptus, Murospora friendii, Densosporites bialatus, D. dupli- G. PLAYFORD: LOWER CARBONIFEROUS MICROFLORAS 671 earns, D. rarispinosus, Lycospora uber, Lophozonotriletes appendices, Cirratriradites Solaris, &c. Age — Visean. 10. Carronelva. Sample G1080 contains a very sparse microflora, which, in contain- ing Murospora aurita, M. tripulvinata, and Lycospora uber, is referable to the Aurita Assemblage. Age — Visean. 1 1 . Gerritelva. Sample 353 yielded a sparse microflora, including the following species diagnostic of the younger assemblage : Murospora aurita, M. tripulvinata, Densosporites rarispinosus, Lycospora uber, Lophozonotriletes appendices, Diatomozonotriletes saetosus, and Monilospora dignata. In particular, the presence of the latter species suggests corre- lation with the stratigraphically highest sample (G1 102) of the Birger Johnsonfjellet succession. Age — Upper Visean, or possibly lowermost Namurian. More abundant and diverse assemblages were recovered from samples 390 and 391. The following forms, diagnostic of the Aurita Assemblage, were identified from both samples: Murospora aurita, Reticulatisporites peltatus, Lycospora uber, and Cirra- triradites Solaris. Age — Visean. 12. Margaretbreen. Sample G1339 contains a diverse and well-preserved microflora with many species characteristic of the younger assemblage. These include: Murospora aurita, M.friendii, Triquitrites trivalvis, Densosporites bialatus, D. duplicatus, D. aculeatus, Lycospora uber, Camptozonotriletes velatus, Diatomozonotriletes saetosus, and Spino- zonotriletes balteatus. Age — Visean. A much less abundant microflora was obtained from sample G1344. Although Murospora aurita was not identified, the Aurita Assemblage is represented by such forms as Lycospora uber, Camptozonotriletes velatus, and Retialetes radforthii. The latter species suggests correlation with the uppermost parts of the successions at Triungen and Birger Johnsonfjellet. Age — Upper Visean, or possibly lowermost Namurian. 13. Svenbreen. Sample E363, from just above the base of the Billefjorden Sandstones, includes the following representatives of the younger assemblage: Murospora aurita, Reticulatisporites variolatus, Densosporites bialatus, D. rarispinosus, Lycospora uber, Cirratriradites elegans, Camptozonotriletes velatus, and Diatomozonotriletes hughesii. Also present is Convolutispora harlandii, which, together with the above species, suggests correlation of this sample with approximately the same horizon as sample G1095 of the Birger Johnsonfjellet succession. Age — Visean. 14. Odellfjellet. Sample B680 yielded a well-preserved microflora. The Rarituber- culatus Assemblage is represented diagnostically by such forms as Lophozonotriletes rarituberculatus, L. variver rucatus, Punctatisporites labiatus, Verrucosisporites gobbettii, Dictyotriletes caperatus, Anulatisporites canaliculatus, and Velosporites echinatus. Age — Tournaisian. From stratigraphically higher beds, samples B624 and H267 yielded diverse micro- floras referable to the Aurita Assemblage. Species common to both samples include: Murospora aurita, Reticulatisporites peltatus, Densosporites aculeatus, Lycospora uber, Lophozonotriletes appendices, Cirratriradites elegans, and Camptozonotriletes velatus. Age — Visean. 15. Alandvatnet. Comparatively poorly preserved microfloras were recovered from samples B616 and B619. Both contained the following species, which are diagnostic of the younger assemblage: Murospora aurita, Densosporites bialatus, Lycospora uber, Cirratriradites elegans, and Camptozonotriletes velatus. Age — Visean. 672 PALAEONTOLOGY, VOLUME 5 16. Lemstromfjellet. Sample B443 contains a sparse microflora, including the follow- ing characteristic representatives of the Aurita Assemblage : Mwospora aurita, Anapicu- latisporites concinnus, and Lycospora uber. Age — Visean. 17. Blarevbreen. Prolific and closely similar microfloras were recovered from samples M365, Q55, and Q56. Amongst the forms, common to all or at least two of these samples, and diagnostic of the Aurita Assemblage, are: Murospora aurita , M. friendii , M. strigata , Waltzispora albertensis , Reticulatisporites variolatus , R. peltatus , Triquitrites trivalvis , Densosporites bialatus, D. duplicatus, D. rarispinosus, Lycospora uber , Cirratriradites elegans , Camptozonotriletes velatus , Diatomozonotriletes saetosus, D. hughesii , Remvsporites albertensis , and Retialetes radforthii. This spore association is very similar to that encountered in the stratigraphically highest samples from Triungen and Birger Johnsonfjellet. Age — Visean, or possibly lowermost Namurian. Bjonwya 1. Nordkapp. A few species only were positively identifiable in the poorly preserved microfloras recovered from samples P702 and P725. Sample P702 contains the following stratigraphically significant forms: Densosporites bialatus, Lycospora uber , and Diatomo- zonotriletes saetosus. Sample P725 includes Anapiculatisporites concinnus , Lycospora uber, and SpinozonotrUetes balteatus. Although neither sample appears to contain the ‘index’ species Murospora aurita, their microfloras are clearly referable to the Aurita Assemblage. Age — Visean. From the above it is evident that the majority of the samples may be correlated with the upper parts of the Birger Johnsonfjellet and Triungen successions, by virtue of their content of representatives of the Aurita Assemblage. Moreover, the fact that many of these younger samples — specifically those from Ebbadalen (north side), Svenbreen, and Blarevbreen — are from basal beds suggests that in some places Culm deposition may have commenced relatively late in the Lower Carboniferous. Apart from the localities of the three reference successions, only one sample (from Odellfjellet) contained the Rarituberculatus Assemblage. In addition two samples from higher in the Odellfjellet section yielded the younger assemblage. Thus this section is comparable in age (Tournaisian-Visean) to those of Birger Johnsonfjellet and Triungen. BOTANICAL RELATIONSHIPS The outstandingly successful stratigraphical applications of dispersed-spore studies over the past two decades have tended to transcend the fundamentally botanical nature of palynology. Indeed, the botanical origin of many Carboniferous spore genera is at present unknown. Such workers as Chaloner (1953#, b; 1954; 1958#, b ), W. and R. Remy (1957), and Sen (1958) have contributed considerably to our knowledge of the botanical affinities of some of the more characteristic sporae dispersae of Carboniferous age. As a result it is now possible to deduce the existence of certain plant groups solely on the basis of dispersed-spore evidence. As listed by Nathorst (1914) and Forbes et al. (1958), the macroflora of the Spits- bergen Culm consists predominantly of arborescent lycopods including numerous representatives of Lepidodendron and Bothrodendron. The presence of Lepidodendron is almost certainly reflected in the microflora by the abundance of Lycospora (occurring as MICROFLORAL ASSEMBLAGE RA R IT UBERCULATUS A U R I T A SUGGESTED AGE TOURNAISIAN VISEAN, possibly to NAMURI AN A Leiotriletes micpogranulatus Punctatisporites labiatus Veppucosispopites gobbettii Lophotri letes coniferus Acanthotpiletes mipus Convolutispora vermiformis D i ct yot Pi 1 et es capepatus R et i c u 1 a t i s po p i t e s planus S t e n o z o n o t p i l et e s stenozonalis S t e n o z o n o t p i 1 e t e s inductus Anulati spopites c a n a 1 i c u 1 a t u s Densospopites stPiatifenus D e n s o s p o p i t e s vapiomapginatus Knoxispopites hedepatus C p i s t a t i s po p i t e s echinatus LophozonotPiletes papitubepculatus L o ph o z o n o t p i 1 e t e s dentatus LophozonotPiletes variveppucatus TholispoPites foveolatus Velospopites echinatus S p i n o z o n o t p i 1 e t e s uncatus Cyclogpanispopites flexuosus C on vo 1 ut i s po pa tubepculata R et i c u 1 a t i s po p i t e s cancellatus Tripaptites incisotrilobus S t e n o z o n ot p i 1 et e s clapus A n u 1 a t i s po p i t e s labiatus Densospopites dentatus Densospopites intepmedius Densospopites spitsbepgensis L a b i a d e n s i t e s fimbriatus Knoxispopites litepatus Endospopites micpomanifestus Radialetes costatus Waltzispopa lobophopa Waltzispopa albertensis Veppucosispopites eximius R e t i c u 1 a t i s po p i t e s vapiolatus R et i c u 1 a t i s po p i t es peltatus Fo veospopites insculptus TpiquitPites tpivalvis Tpipaptites complanatus Mupospora aurita Mupospopa fpiendii Densospopites bialatus Densospopites duplicatus Densospopites papispinosus Densospopites aculeatus Lycospopa uber LophozonotPiletes appendices Potoni es pones delicatus Cirratpipadites solapis C i p pa t r i pa d i t es elegans Camptozonotriletes velatus D i a t o m o z o n o t ri 1 et e s saetosus D i a t o m o z o no t Pi 1 et e s hughesii S pi n ozo n o t p i 1 et e s balteatus table 5. Summary compilation of important constituent species of the two Microfloral Assemblages delineablein the Lower Carboniferous of Spitsbergen. The indicated probable age of each Assemblage is discussed in detail in the text. Correction: for Densosporites intermedins read D. diatretus (see p. 623). 674 PALAEONTOLOGY, VOLUME 5 a single species, Lycospora uber ), since this spore genus has been found associated else- where only with various species of the cone Lepidostrobus (see Chaloner 19536; Sen 1958). In view of the total absence of Lycospora uber in the older microfloral assemblage, it is tempting to surmise the appearance, in Spitsbergen at least, of its parent plant in early Visean times. Lycopods are probably also represented by the numerous species of Densosporites which occur throughout the Spitsbergen Culm. Chaloner (1958a) attri- buted a heterosporous cone, containing Densosporites- type microspores, to the herba- ceous lycopod Se/aginellites, but Bharadwaj (1959) recommended the inclusion of this cone in the genus Bothrostrobus. The spores described herein as Densosporites spits- bergensis are closely similar to those recovered by Bharadwaj (1959) from the Spitsbergen Lower Carboniferous fructification Porostrobus zeilleri (described originally by Nathorst 1914). Bharadwaj considered that P. zeilleri ‘ shows lepidodendroid as well as sigillarioid characters’. Other probable Lycopsidean derivatives are the genera Endosporites (see Chaloner 1953a, 19586) and Cirratriradites (see Chaloner 1954; Hoskins and Abbott 1956) . These genera are represented respectively in the Lower Carboniferous of Spits- bergen by Endosporites micromanifestus, and by Cirratriradites elegans and C. Solaris. It should be noted, however, that the two species of Cirratriradites bear little resemblance to the C. annulatus-type microspores recovered from Selaginel/ites suissei and from S. crassicinctus by Chaloner (1954) and Hoskins and Abbott (1956) respectively. From available literature, no definite pronouncement can be made concerning the origin of the numerous other microspore genera represented in the Spitsbergen Culm. Especial caution is necessary in assessing the botanical relationships of simple, relatively unsculptured generic groups such as Calamospora, Punctatisporites, and Leiotriletes. Forms of this general type are known to derive from numerous plant groups including, for example, Bryophyta, Psilophytales, Equisetales, and Filicales. Fern-like plants prob- ably contributed the bulk of azonate, often prominently sculptured, trilete spores such as Cyclogranisporites, Acanthotriletes, Anapiculatisporites, Verrucosisporites, Con- volutispora, and Reticulatisporites (cf. Potonie and Kremp 1956 b; W. and R. Remy 1957) . There appears to be no evidence regarding the affinity of cingulate forms such as Murospora , Stenozonotriletes, Anulatisporites, Labiadensites, Knoxisporites, Lopho- zonotriletes , &c., but some of these may well be of lycopsid origin. The genus Florinites, which is well known from the Upper Carboniferous as derived from cordaite and conifer vegetation, is conspicuously absent in the Spitsbergen Culm. Indeed, Monosaccites com- prises an essentially minor element of the microfloras; such genera as Remysporites and Velosporites may perhaps be of pteridosperm origin. The presence in minor amounts of Chaetosphaerites and Tetraporina suggests strictly subordinate fungal and algal con- tributions respectively. Some consideration has already been given to differences in microspore composition of various lithological types (see text-fig. 1 2), all of which contain the Aurita Assemblage. In the coal (E363) and the highly carbonaceous shale (R38), Densosporites spp. and Murospora aurita are respectively the dominating forms in microfloras which show a marked paucity in generic and specific representation. These species are relatively heavy, cingulate forms and were probably not very readily dispersed by wind or water. Thus their extreme abundance in coaly sediments may suggest that the parent plants were components of the coal swamp vegetation. Lycospora uber is a relatively trivial con- stituent of both E363 and R38. In contrast, the shales (G1098, G1466) and the sand- G. PLAYFORD: LOWER CARBONIFEROUS MICROFLORAS 675 stone (G1102) all contain diverse, essentially similar microfloras (having high specific and generic representation) which are probably fairly representative of the overall con- temporary flora. In all three samples, Lycospora uber is the most abundant type, but accompanied by significant amounts of Densosporites spp. and Murospora aurita. L. uber is a small, relatively light spore which was probably dispersed widely from its parent arborescent lepidodendrid, and was perhaps eclipsed in the coal microflora by a dominance of heavier, less dispersable forms (as Densosporites spp. and Murospora aurita ). CONCLUSIONS The Lower Carboniferous sediments of Spitsbergen contain diverse and some excep- tionally well-preserved microfloras. The vertical distribution of the microspore species, as observed in the Billefjorden Sandstones sections at Birger Johnsonfjellet, Triungen, and Citadellet, provides an effective means of stratigraphical correlation both within and outside Spitsbergen. Indeed, the present study lends considerable support to the view expressed by Ishchenko (1956, p. 135) to the effect that terrestrial sequences of Lower Carboniferous age may be subdivided precisely on the exclusive basis of their microspore content. There is some evidence that a third microfloral assemblage may be delineable. This would incorporate the youngest microfloral elements (e.g. Retialetes radforthii ) which indicate an Upper Visean or lowest Namurian age. A subdivision of the Aurita Assemblage would thus be entailed, but precise delimitation is not possible from samples available at present. External correlation is afforded by the strikingly close similarity between the micro- floras described herein and those reported previously from the Lower Carboniferous of Russia, and from portions of the Mississippian of Canada. In terms of the standard European stages, the age of the Billefjorden Sandstones is shown to range from Tour- naisian to at least Visean and perhaps lower Namurian; this endorses and strengthens the preliminary view of Hughes and Playford (1961). In terms of North American (Mississippian) nomenclature, the series ranges in age from Kinderhook to lower or middle Chester. The fact that basal Culm samples, from often not widely separated localities, are of different ages suggests that the initiation of Culm sedimentation was not everywhere contemporaneous. Such variation in the age of local base levels is not unusual in a con- tinental sequence which developed over an irregular landscape. The disconformity at the top of the Billefjorden Sandstones at both Triungen and Birger Johnsonfjellet indicates that Culm sedimentation may have continued well into the Namurian. As noted previously the highest collected Culm sediments from the south side of Ebbadalen (samples B609, F531, &c.) indicate an Upper Visean or lower- most Namurian age. However, this coaly horizon is succeeded by a further 220 feet of Culm which passes by vertical transition into the Lower Gypsiferous Series (see McWhae 1953, fig. 6, stratigraphical column H). These upper Culm beds may well be Namurian A in age; the age of the Lower Gypsiferous Series is not definitely known, but is thought to be Upper Namurian or Bashkirian (Forbes et al. 1958, p. 470 and table 2). 676 PALAEONTOLOGY, VOLUME 5 APPENDIX A. DATA ON SAMPLES STUDIED Samples are listed and described macroscopically under headings of the localities from which they were collected. Actual collector is referred to by initials: M. B. Bayly, D. E. T. Bidgood, M. H. P. Bott, C. L. Forbes, J. L. Fortescue, P. F. Friend, D. G. Gee, D. J. Gobbett, W. B. Harland, J. R. H. McWhae, B. Moore, G. Playford, O. P. Singleton, M. S. Thornton, C. B. Wilson, J. M. Wordie. The initials are followed by the preparation numbers of each sample — those prefixed with ‘M’ were prepared by Mrs. Margaret Mortimer; ‘P’ indicates preparation by the writer. Birger Johnsonfjellet G1086 sandstone, pale grey, hard, medium-grained, micaceous, with plant fragments; D. J. G.; PI 69. G1087 sandstone, dark grey, hard, medium-grained, carbonaceous, micaceous; D. J. G.; P161, PI 70. G1088 shale, black, silty, carbonaceous, micaceous, with plant fragments; D. J. G.; P162, P171. G1089 siltstone, black, carbonaceous, micaceous, with plant fragments; D. J. G.; P163. G1090 siltstone, reddish-brown to black, very hard, ferruginous, carbonaceous; D. J. G. ; P177. G1091 shale, black, highly carbonaceous, with plant fragments; D. J. G.; P139, P143. G1092 shale, black, highly carbonaceous, with plant fragments; D. J. G.; PI 58. G1093 shale, black, highly carbonaceous, with plant fragments; D. J. G.; P159. GI095 shale, dark grey, silty, carbonaceous, micaceous, with plant fragments; D. J. G.; P164. G1096 sandstone, pale grey, hard, medium-grained; D. J. G.; PI 78. G1098 shale, black, carbonaceous; D. J. G.; PI 67. G1099 shale, black, carbonaceous; D. J. G.; P160. G1 101 shale, black, highly carbonaceous, with plant fragments; D. J. G. ; P168. G1102 sandstone, dark grey, fine-grained, silty, carbonaceous, micaceous; D. J. G.; P180, P188. Triungen G1473 shale, dark grey, carbonaceous; D. J. G.; P147. G1472 siltstone, black, carbonaceous, micaceous; D. J. G.; P148. G1471 sandstone, pale grey, hard, fine-grained, with carbonaceous, silty lenses; D. J. G. ; P179. G1470 shale, black, carbonaceous, with plant fragments; D. J. G.; P149. G1469 shale, black, highly carbonaceous, with plant fragments; D. J. G. ; PI 52. G1468 shale, black, highly carbonaceous; D. J. G.; PI 5 1 . G1467 shale, black, highly carbonaceous; D. J. G.; PI 54, PI 57. G1466 shale, black, carbonaceous, micaceous, with coaly lenses; D. J. G. ; P145. G1465 shale, black, clayey, highly carbonaceous; D. J. G.; PI 53. G1461 shale, black, carbonaceous; D. J. G. ; P155. Citaciellet B685 sandstone, grey, fine-grained, massive, carbonaceous, micaceous, with plant fragments; B. M.; M81 1, M928, M949, P003. B687 sandstone, grey, fine-grained, silty, carbonaceous, micaceous, with plant fragments; B. M.;P226. G1445 sandstone, grey-black, fine-grained, silty, carbonaceous, micaceous; D. J. G.; PI 72. G1446 shale, black, carbonaceous, micaceous; D. J. G. ; P173. G1448 shale, grey-black, carbonaceous, micaceous, very fissile; D. J. G.; P174. G1450 shale, black, carbonaceous, very fissile; D. J. G. ; P175. G1451 shale, black, carbonaceous, very fissile; D. J. G.; P176. G1452 sandstone, dark brown, fine-grained, massive, carbonaceous, ferruginous; D. J. G. ; P206. G1453 shale, grey-black, carbonaceous, very fissile; D. J. G.; P181. Ebbadalen ( north side) B706 sandstone, grey, fine-grained, silty, carbonaceous, micaceous, with ‘ Knorria’; B. M.; P012. W860 shale, black, carbonaceous, micaceous; C. B. W. ; P017. G. PLAYFORD: LOWER CARBONIFEROUS MICROFLORAS 677 Ebbcidcilen ( south side) B604 bright coal; B. M.; P018. B609 siltstone, grey, carbonaceous, micaceous, with Cardiopteridium ? spetsbergense Nathorst; B. M.; M803. F531 shale, black, highly carbonaceous, with Lepidodendron rhodeanum Sternberg; P. F. F. ; M788, P225. F774 siltstone, black, carbonaceous, micaceous, with plant fragments; P. F. F. ; P021. G332 shale, black, carbonaceous, with plant fragments; D. J. G.; P024. G334 shale, black, highly carbonaceous, with plant fragments; D. J. G.; P076. G366 shale, black, carbonaceous, with Lepidophloios scoticus Kidston; D. J. G.; P077. G382 siltstone, black, carbonaceous, micaceous, with Cardiopteridium ? spetsbergense Nathorst; D. J. G. ; P029. Wordiekammen ( north side) S59a dull coal; O. P. S.; M883, PI 50. Adolf bukta ( north shore) W217 shale, black, highly carbonaceous, with plant fragments; J. M. W. ; P034. De Geerfjellet G636 shale, black, carbonaceous, with plant fragments; D. J. G.; P026, PI 86. T269 shale, black, highly carbonaceous, some layers consisting almost entirely of megaspores; M. S. T.; P 14 1 . Ragnarbreen R38 shale, black, highly carbonaceous, with plant fragments; J. R. H. McW.; M821, P182. Anservika R5 sandstone, grey, fine-grained, hard, micaceous, slightly carbonaceous; J. R. H. McW.; P011. F20 dull coal; C. L. F.; M822, P083. D120 sandstone, dark grey, fine-grained, hard, carbonaceous, micaceous, with plant fragments; D. E. T. B. ; P033. G1283 siltstone, dark grey, carbonaceous, micaceous, with plant fragments; D. J. G.; P236. G1280 sandstone, grey-black, fine-grained, carbonaceous, micaceous, with plant fragments; D. J. G.; PI 56. G1278 siltstone, grey, sandy, carbonaceous, micaceous, with plant fragments; D. J. G.; P235. G1276 sandstone, grey-black, fine-grained, silty, carbonaceous, micaceous; D. J. G.; P234. Carronelva G1080 siltstone, grey-black, sandy, carbonaceous, micaceous, weathered, with plant fragments; D. J. G.; P207. Gerritelva 353 bright coal ; W. B. H. ; P01 5. 390 shale, grey-black, carbonaceous, micaceous, with Lepidophloios sp. and Cardiopteridium ? spetsbergense Nathorst; W. B. H.; P064. 391 shale, grey-black, carbonaceous, micaceous, with Cardiopteridium ? spetsbergense Nathorst; W. B. H.; M810, P004. Margaretbreen G1339 shale, black, carbonaceous, with plant fragments; D. J. G.; P184. G1344 shale, dark grey, carbonaceous, micaceous, with plant fragments; D. J. G.; P203. Svenbreen E363 dull coal; D. G. G.; P140. PALAEONTOLOGY, VOLUME 5 Odellfjellet B680 shale, black, carbonaceous, micaceous, with Cyclostigma sp. ; B. M. ; M809, P224. B624 siltstone, grey, carbonaceous, micaceous, with plant fragments; B. M.; M806, P002. H267 shale, black, highly carbonaceous, with Stigmaria; W. B. H.; M797, P086. Alandvatnet B616 sandstone, pale grey, fine-grained, massive, with plant fragments; B. M.; M807, P089. B619 sandstone, grey, fine-grained, massive, with plant fragments; B. M.; P081. Lemstromfjellet B443 sandstone, pale grey, medium-grained, massive, with irregular intercalations of carbona- ceous, fine-grained sandstone and siltstone; M. H. P. B.; P053. Blarevbreen M365 shale, black, silty, carbonaceous, micaceous, with plant fragments; M. B. B.; P202. Q55 shale, black, carbonaceous; J. L. F.; P146, P165. Q56 shale, black, carbonaceous, with plant fragments; J. L. F.; PI 66. Nordkapp, Bjormya P702 shale, black, carbonaceous, weathered, with plant fragments; G. P.; PI 27. P725 shale, grey-black, carbonaceous, with Lepidodendron spetsbergense Nathorst, ‘ Knorria and Carpolithus sp.; G. P. ; PI 34. APPENDIX B. NOTE ON SPECIMENS ILLUSTRATED BY HUGHES AND PLAYFORD (1961) Sedgwick Museum Specimen numbers (L.880-L.938) have been allocated to type and other figured specimens of the preliminary study by Hughes and Playford (1961). CONTENTS OF PARTS ONE AND TWO page Introduction 550 Acknowledgements 551 References 552 Stratigraphy 556 Previous investigations of Lower Carboniferous microfloras 563 Preparation and examination of samples 569 Systematic descriptions of dispersed spores 571 Anulatisporites labiatus — Part I ends 618 Part II begins — Anulatisporites orbiculatus 619 Microfloral assemblages and stratigraphical applications 660 Delineation of microfloral assemblages 660 Age of the microfloral assemblages 665 Correlation within Svalbard 668 Botanical relationships 672 Conclusions 675 Appendix A. Data on samples studied 676 Appendix B. Note on specimens illustrated by Hughes and Playford (1961) 678 GEOFFREY PLAYFORD Department of Geology and Mineralogy, University of Queensland, St. Lucia, Brisbane, Manuscript received 17 November 1961 Australia SECTIONS OF SOME SPORES FROM THE LOWER CARBONIFEROUS OF SPITSBERGEN by MARY E. DETTMANN and G. PLAYFORD Abstract. Sections of four Lower Carboniferous dispersed-spore species, Labiadensites fimbriatus (Waltz) Hacquebard and Barss, Cristatisporites echinatus Playford, Camptozonotriletes velatus (Waltz) Playford, and Spinozonotriletes uncatus Hacquebard, are discussed and illustrated. In a recent paper, Hughes, Dettmann, and Playford (1962) discussed and illustrated sections of selected Carboniferous spore species and demonstrated the usefulness of sections in the morphological interpretation of spores with equatorial wall thickenings. The present paper incorporates sections of four of the microspore species which Play- ford (1962 — this volume) described from the Lower Carboniferous succession of Spits- bergen. Two of these species are cingulate, one is zonate, and one, provisionally assigned to Incertae Sedis by Playford, shows wall features similar to those of mesospore types. All the sections illustrated in PI. 96 were cut at 3/x intervals transverse to the equa- torial plane; the sectioning technique is described in Hughes, Dettmann, and Playford (1962). For each illustrated specimen, the preparation and slide number, followed by the reference co-ordinates of Leitz Laborlux microscope no. I , and registered numbers (prefixed L) of the Sedgwick Museum, are stated. Precise locality and stratigraphical details are given in Playford (1962). Acknowledgements. Grateful acknowledgement is made by M. E. D. to the International Federation of University Women for the award of the Ida Smedley Maclean Fellowship; and by G. P. to the Australian Commonwealth Scientific and Industrial Research Organization for the award of an Over- seas Postgraduate Studentship. SYSTEMATIC SECTION Anteturma sporites H. Potonie 1893 Turma zonales (Bennie and Kidston) R. Potonie 1956 Subturma zonotriletes Waltz 1935 Infraturma cingulati Potonie and Klaus 1954 Genus labiadensites Hacquebard and Barss 1957 Labiadensites fimbriatus (Waltz) Hacquebard and Barss 1957 Plate 96, figs. 1, 2 Discussion. Sections clearly show the differentiated cingulum, which consists of a rela- tively wide, thick, non-tapering inner portion and a narrow, ‘frilled’ outer portion. Inner and outer portions connected only at the proximal and distal surfaces of the cingulum. Exine one-layered; forms the broad, flat, laesurate lips. [Palaeontology, Vol. 5, Part 4, 1962, pp. 679-81, pi. 96.] 680 PALAEONTOLOGY, VOLUME 5 Genus cristatisporites Potonie and Kremp 1954 Cristatisporites echinatus Playford 1962 Plate 96, figs. 3-5 Discussion. The exoexine, which envelops the thin homogeneous intexine, forms the wedge-shaped cingulum, the laesurate lips, and the distal spinose sculptural elements. The sections also show an inner differentiated zone of the exoexine, but this may be due to corrosion. Infraturma zonati Potonie and Kremp 1954 Genus camptozonotriletes Staplin 1960 Camptozonotriletes velatus (Waltz) Playford 1962 Plate 96, figs. 10-12 Discussion. The zona of this species is relatively thin, and near the equator it appears to enclose a cavity. Exine two-layered; exoexine forms zona and surrounds the thinner intexine (PI. 96, fig. 12). INCERTAE SEDIS Genus spinozonotriletes Hacquebard 1957 Spinozonotriletes uncatus Hacquebard 1957 Plate 96, figs. 6-9 Discussion. Sections show that the exoexine, which is composed of granules, loosely envelops the homogeneous intexine. Exoexine shows spinose sculpture and forms the elevated lips of the laesurae. Conflicting interpretations of the wall stratification of this species have been presented by previous authors. Hacquebard (1957) designates the outer sculptured layer as a peri- spore, whereas Potonie (1960) suggests that the thin inner layer is a mesospore. Some EXPLANATION OF PLATE 96 All figures X 500 unless otherwise specified ; from unretouched negatives. Figs. 1, 2. Labiadensites fimbriatus (Waltz) Hacquebard and Barss 1957. Sections of specimen with one-layered exine showing differentiated cingulum. Preparation P148/S45b/3-4. 1, 32-9 125-1 (L.1270h); 2, 27-0 123-0 (L.1270i). Figs. 3-5. Cristatisporites echinatus Playford 1962. Sections of specimens with two-layered exine consisting of an inner homogeneous intexine and an outer differentiated exoexine which forms the wedge-shaped cingulum and distal spinae. 3, Preparation P148/S46b/2, 26-8 115-1 (L.1271e); 4, Preparation P148/S46c/2, 61-4 122-7 (L.1272d); 5, x 1,000, Preparation P148/S46c/2, 47-3 122-2 (L.1272g). Figs. 6-9. Spinozonotriletes uncatus Hacquebard 1957. Sections showing exine consisting of an inner, homogeneous intexine and an outer, sculptured exoexine which is composed of granules and forms the elevated lips of the laesurae. Preparation P148/S44a. 6, 44-9 113-0 (L.1273c); 7, 54-8 115-3 (L.1273f); 8, 9, Polar section 59-1 118-2 (L.1273g), 9, X 1,000. Figs. 10-12. Camptozonotriletes velatus (Waltz) Playford 1962. Sections of specimen showing zona and distal muri. Preparation P164/S39a. 10, 52-7 120-2 (L.1274f); 11, 29-7 121-3 (L.1274c); 12, X 1,000, showing two-layered exine, the outer layer (exoexine) forms ‘cavate’ zona. 48-7 120-1 (L.1274e). Palaeontology, Vol. 5 PLATE 96 DETTMANN and PLAYFORD, Sections of microspores M. E. DETTMANN AND G. PLAYFORD: SECTIONS OF SPORES 681 evidence for the latter interpretation is provided by the Spitsbergen specimens. The spores figured by Playford (1962, pi. 94, figs. 4-6) and the sections, illustrated herein, clearly show that the inner wall layer is loosely enveloped, particularly in the equatorial region, by the outer wall layer. Such a wall feature is characteristic of described meso- spore forms, for example Duosporites congoensis Hoeg, Bose, and Manum 1955 and Grandispora spinosa Hoffmeister, Staplin, and Malloy 1955 (see Potonie 1958). Furthermore, as discussed by Playford (1962, p. 657), the thick, sculptured outer wall layer, which forms the conspicuously elevated laesurate lips, shows little morpho- graphical or structural resemblance to either the bladder of typical Palaeozoic mono- saccate spores or the, usually filmy, perispore of perinate spores. REFERENCES hacquebard, p. A. 1957. Plant spores in coal from the Horton group (Mississippian) of Nova Scotia. Micropaleontology, 3, 301-24. hughes, n. f., dettmann, m. e., and playford, g. 1962. Sections of some Carboniferous dispersed spores. Palaeontology, 5, 2, 247-52. playford, g. 1962. Lower Carboniferous microfloras of Spitsbergen. Ibid. 5, 550-678. potonie, r. 1958. Synopsis der Gattungen der Sporae dispersae. II. Teil: Sporites (Nachtrage), Saccites, Aletes, Praecolpates, Polyplicates, Monocolpates. Beih. Geol. Jb. 31, 1-114. 1960. Synopsis der Gattungen der Sporae dispersae. III. Teil : Nachtrage Sporites, Fortsetzung Pollenites. Mit Generalregister zu Teil I— III. Ibid. 39, 1-189. MARY E. DETTMANN Department of Geology, Sedgwick Museum, Cambridge GEOFFREY PLAYFORD Department of Geology and Mineralogy, University of Queensland, St. Lucia, Brisbane, Australia Manuscript received 20 November 1961 THE EOSPIRI FERID AE by A. J. BOUCOT Abstract. The impunctate, spire-bearing family Eospiriferidae contains the subfamilies Eospiriferinae and Cyrtiinae. The Eospiriferinae appear in the Upper Llandovery and persist until the Eifelian; whereas the Cyrtiinae appear in the Upper Llandovery and persist with certainty until the close of the Ludlow, but there is a single specimen from beds of Emsian age in Czechoslovakia. The family is characterized by the possession of radial filar ornamentation externally combined with a spiriferoid form. Internally, the brachial valve is charac- terized by having long crural plates on either side of a linear, unstriated diductor attachment area. The interior of the pedicle valve is relatively generalized. The eospiriferids disappear from the Western Hemisphere at the end of the Gedinnian, but continue on into the Eifelian in part of the Old World. In the Old World, the eospiriferids are absent from the Rhenish facies of the Devonian, as well as the Devonian of South Africa and Antarctica. The genus Plicocyrtia is proposed for laterally plicate cyrtiinids, and the genera Havlicekia , Macropleura, and Nikiforovaena for eospiriferinids with external forms differing substantially from previously described members of the subfamily. The genera Najaclospirifer and Pinguispirifer are rejected from the Eospiriferidae on the basis of differing internal structures and external fine ornamentation. The evolution of plicated eospiriferids from unplicated forms is discussed. In the course of a study of Silurian and early Devonian spiriferids, it became apparent to the writer that the eospiriferids were morphologically so far removed from any of the subfamilies of the Spiriferidae (King 1846) that they should be assigned to a separate family, the Eospiriferidae. The eospiriferids, world-wide in distribution (text-fig. 1), are of value in subdividing the Silurian. They appear, near the end of Llandoverian time, fully developed on both sides of the North Atlantic. No closely related precursors of the eospiriferids have been reported from strata of Lower or Middle Llandoverian age, but strata of those ages will doubtless eventually produce closely related genera and species. The disappearance of the family was relatively slow in Bohemia, the Carnic Alps, northern Trance, North Africa, the region of the Bosphorus, central Asia, the Ap- palachians, and New Zealand, with members of the family in some areas persisting into the Middle Devonian (text-figs. 2, 3), but was relatively rapid in the Malvinokaffric facies of South America and South Africa (text-fig. 1) and in the Rhenish facies of Germany (‘ Spirifer ’ solitarius Krantz possesses neither the internal nor external charac- teristics of an eospiriferid), Belgium, southern England, Poland, and Nova Scotia, where representatives of the family may be found in the late Silurian but not in the early Devonian. Prom the first appearance of the family in late Llandoverian time two lineages, here assigned to the subfamilies Eospiriferinae Schuchert and LeVene 1929 (emended) and the Cyrtiinae Predericks 1924, are distinct and well developed. The writer acknowledges with pleasure the criticisms of Dr. J. E. Hede, Lund University ; Dr. Valdar Jaanusson, Uppsala University; Dr. Jean Berdan and Dr. Charles Merriam, U.S. Geological Survey; and Dr. T. W. Amsden, Oklahoma Geological Survey, each of whom read the manuscript. Photo- graphs of Nikiforovaena ferganensis were provided by Dr. O. Nikiforova, Leningrad, and specimens of Janius insignis by Dr. Hede. Ing. Jose Carrillo Bravo, Petroleos Mexicanos, Tampico, Tamaulipas, provided the collections from which the Ciudad Victoria eospiriferids were extracted. Dr. M. A. Rzonsnitskaya, Leningrad, made a number of useful comments regarding Soviet stratigraphy and eospiriferids. Prof. D. Nalivkin, Leningrad, arranged for the writer to study the material in the Tscherny- [Palaeontology, Vol. 5, Part 4, 1962, pp. 682-711, pis. 97-104.1 A. J. BOUCOT: THE EOSPIRIFERIDAE 683 text-fig. 2. Known distribution of eospiriferids in strata of Siegenian to Emsian age. Yy 684 PALAEONTOLOGY, VOLUME 5 chev Geological Museum. Dr. V. Havh'cek, Prague, discussed the manuscript with the writer and pointed out the peculiar ornamentation of ‘ Eospirifer' secans and ‘ E . ’ turjensis. Dozent Dr. F. Prantl, Prague, made available for the study the rich collections in the National Museum. Mr. Winfried Haas, Bonn, gave the writer an opportunity to collect Eospirifer and Cyrtia from strata he is studying in the Istanbul region. Dr. Brian Norford, Geological Survey of Canada, Ottawa, provided information on the occurrence of Cyrtia in the Silurian of British Columbia. Much of the research for this paper was sup- ported by a National Science Foundation grant to the Massachusetts Institute of Technology ( DSR contract 298). text-fig. 3. Known distribution of eospiriferids in strata of Eifelian age. SYSTEMATIC DESCRIPTIONS Superfamily spiriferacea King 1846 Family eospiriferidae Schuchert and LeVene 1929 (nom. transl. Boucot, herein, et Eospiriferinae Schuchert and LeVene 1929) Diagnosis. Impunctate spiriferids with fine ornamentation consisting of fila which bifurate anteriorly and which originate anteriorly by implantation. The fila do not have spinose anterior terminae and are crossed by concentric growth-lines which may or may not be nodose. The delthyrium is either completely or partially closed by discrete deltidial plates which in large specimens become medially conjunct, enclose a foramen, and in many specimens are then overlain by an outer layer which simulates a pseudodeltidium. In the brachial valve long crural plates support the discrete hinge plates. Discrete chilidial plates may be present and in large specimens may be medially conjunct. The area of diductor attachment is unstriated. The ribbon-like crura and primary lamella form an A. J. BOUCOT: THE EOSPIRIFERIDAE 685 obtuse angle where they join above the short jugal process. In the pedicle valve long dental lamellae are present. Comparison. The Eospiriferidae may be distinguished from the contemporaneous Delthyrinae and Kozlowskiellininae by the presence of long crural plates in the brachial valve, and by the absence of a striated diductor attachment area in the brachial valve and of external striations terminating anteriorly over the edge of each growth lamella as a fringe of minute spines. The Cyrtinopsidae possess crenulated growth lamellae that are unstriated radially. Distribution. World-wide in strata of Upper Llandoverian to Eifelian age. Subfamilies. Eospiriferinae Schuchert and LeVene 1929 (emended) and Cyrtiinae Fredericks 1924. Subfamily eospiriferinae Schuchert and LeVene 1929 (emended) Diagnosis. Members of the Eospiriferidae having a convex, but not pyramidal, pedicle valve and a triangular, but not narrowly elongate, delthyrium. The deltidial plates are usually narrow, border the delthyrial cavity, and are inserted normal to the interarea. In some specimens the deltidial plates may coalesce to form a pseudodeltidium. Genera: Eospirifer Schuchert 1913, in Zittel-Eastman, Textbook of Paleontology , 1, 2nd ed., p. 411. Striispirifer Cooperand Muir-Wood 1951, /. Washington Acad. Sci. 41, 6, p. 195 (= Schuchertia Fredericks 1926). Janius Havlicek 19576, p. 247. Havlicekia gen. nov. Macropleura gen. nov. Nikiforovaena gen. nov. Genera rejected: Najadospirifer Havlicek 19576, p. 246. Restudy of topotype material shows that the type species of this genus possesses short crural plates and a striated area for diductor attachment in the brachial valve; the fine ornamentation consists of coarse spinules distributed along growth lamellae in a fashion similar to that of the reticularids. Pinguispirifer Havlicek 19576, pp. 246-7. Restudy of topotype material shows that the type species of this genus does not possess low, eospiriferid-type crural plates or a smooth, narrow notothyrial chamber for diductor attachment in the brachial valve. The musculature of the pedicle valve is unlike that of the Eospiriferidae. The finely striate ornamentation is not well enough preserved on the specimens studied to suggest the familial affinity of this genus. Distribution. World-wide in strata of Upper Llandoverian to Eifelian age. Genus eospirifer Schuchert 1913 Plate 97, figs. 1-15 Type species. Spirifer lineatus J. de C. Sowerby 1825, Mineral Conchology, 5, p. 151, pi. 493, figs. 1-2. Diagnosis. Eospiriferinids having unplicated flanks, fold, and sulcus, as well as an elongate hinge line one-half to almost equal the maximum width. 686 PALAEONTOLOGY, VOLUME 5 Comparison. Eospirifer lacks the lateral plications present in Striispirifer, Macropleura, and Nikiforovaena, and the anteriorly bifurcating plications on the flanks present in Janius. Havlicekia has an acuminate form, extremely high fold in the brachial valve, and striispiriferid-type plications in the early growth stages. Pedicle exterior. Pedicle valve strongly convex, subcircular to laterally ellipsoidal in outline. Lateral margins rounded in forms where the greatest width is anterior of the posterior margin, relatively straight in forms where the greatest width is at the posterior margin. Anterior margin uniplicate. Interarea straight, posteriorly concave, and striated by growth-lines that parallel the hinge-line. Inclination of interarea catacline (for termino- logy of interarea inclination see Schuchert and Cooper 1932, p. 20), but the actual angle is distinctive for each species. The delthyrium encloses an angle of about 60 degrees. Beak straight to strongly incurved. The deltidial structures in small specimens consist of discrete plates bordering the margins of the delthyrium. With increase in size the deltidial plates may coalesce medially to enclose a pedicle foramen, and in larger specimens an outer layer of shell material completely covers the conjunct deltidial plates and foramen, simulating a pseudodeltidium (Beecher and Clarke 1889, pi. 6, figs. 9, 11). When large, the deltidial structures are striated by growth-lines paralleling the hinge-line. Sulcus well developed, gently rounded to subrectangular in cross-section. In some variants the peri- EXPLANATION OF PLATE 97 Figs. 1-6. Eospirifer radiates (Sowerby, 1825). Mulde marl; Djupviks fisklage, Eksta, Gotland. U.S.N.M. No. 84363. 1, Anterior view (xl). Note the relatively broad, low fold and sulcus. 2, Side view (x 1). Note the incurved interarea of the pedicle valve. 3, Posterior view (x 1). 4, Posterior view ( X 2). Note the narrow deltidial plates bordering the delthyrium and inclined normal to the interarea. 5, Brachial view ( X 1). Note the finely striate radial ornamentation and the lack of lateral plications. 6, Pedicle view (x 1). Fig. 7. Eospirifer cf. radiatus (Sowerby, 1825). Chesuncook limestone. U.S.G.S. locality No. 3249-sd, islet about 3 miles south-east from mouth of Quaker Brook, Chesuncook Lake, Piscataquis County, Maine. U.S.N.M. No. 125257. Impression of interior of pedicle valve (x 1). Note the relatively long dental lamellae. Figs. 8-10. Eospirifer radiatus (Sowerby, 1825). Chicago formation; Chicago, Illinois. 8, Posterior view of internal impression (x 1). Note the long, slender, crural plates and the unstriated area of diductor attachment. U.S.N.M. No. 125255b. 9, Impression of interior of pedicle valve (xl). Note the relatively long dental lamellae. U.S.N.M. No. 125255a. 10, Impression of interior of pedicle valve (x 1). Note the long dental lamellae and the variability present between the muscle impressions of this specimen and that illustrated in figs. 7 and 8. U.S.N.M. No. 125255b. Fig. 11. Eospirifer radiatus (Sowerby, 1825). Racine dolomite; Bridgeport, near Chicago, Illinois. Posterior view of impression of interior (x3). Note the relatively long crural plates and the un- striated area of diductor attachment. U.S.N.M. No. 8409. Fig. 12. Eospirifer radiatus (Sowerby, 1825). Racine dolomite; Racine, Wisconsin. Anterior view of cardinalia and dental lamellae ( X 3). Note the laterally flaring hinge plates supported by long crural plates which enclose the narrow, unstriated area of diductor attachment. U.S.N.M. No. 9762. Fig. 13. Eospirifer radiatus (Sowerby, 1825). Waldron shale; Waldron, Indiana. Calcined preparation (x 2) showing short jugal process (outlined in India ink below) directed towards interior of pedicle valve at the junction of the primary lamella of the spire and the crura. Note the change in direction of curvature where the primary lamella and the crura fuse. M.C.Z. No. 9425b. Figs. 14, 15. Eospirifer radiatus (Sowerby, 1825). Racine dolomite; Wisconsin. 14, Dolomitized interior showing spire, jugal process, and crura (x 2). Note the short jugal process and the obtuse angle included by the crura and the primary lamella. M.C.Z. No. 9426. 15, Dolomitized interior showing spire, jugal process, and crura (x2). Note the short jugal process. M.C.Z. No. 9426. Palaeontology, Vol. 5 PLATE 97 BOUCOT, Eospiriferidae A. J. BOUCOT: THE EOSPIRIFERIDAE 687 phery and anterior margin tend to become plicated in larger specimens, but normally no lateral plications or plications in the sulcus are present. Fine ornamentation consists of radial fila intersected, in well-preserved specimens, by concentric growth-lines. The intersections tend to be nodose. Strong growth-lines uncommon, but if present are few in number. Brachial exterior. Valve gently convex, subrounded to laterally elongate in outline. A low fold with a gently rounded to subrectangular cross-section is present. Interarea ortho- cline to gently apsacline, very short in comparison with that of the pedicle valve. Pedicle interior. Delthyrium bordered by two strong dental plates that extend about one- third the length of the shell and support stubby hinge teeth. Almost no secondary material is deposited around the plates except for a small amount in the apex of the valve and the extremities of the umbonal cavities. The dental lamellae diverge from the mid- line at an angle of about 20 to 30 degrees. The muscle field, very poorly impressed except for a low myophragm, extends about one-third of the distance to the anterior margin. Myophragm laterally bounded by anteriorly expanding diductor impressions which are longitudinally striate and posteriorly enclose the small, elliptical adductor impressions. Anterior and lateral periphery of valve smooth. Brachial interior. The cardinalia consist of discrete hinge-plates supported medially by long crural plates. Area of diductor attachment smooth. A low myophragm about one- third the length of the valve bisects the feebly impressed muscle field. Anterior and lateral margins smooth. The dental sockets are closed postero-laterally and flare antero- laterally. The ribbon-like crura make an oblique angle with the primary lamellae. A short jugal process is directed toward the pedicle valve near the junction of the crura and the primary lamellae. St. Joseph (1935, pp. 322-3; pi. xv, fig. 10, text-fig. 3) reports a band connecting the jugal processes medially, but the writer found no evidence of one. Species: Eospirifer consobrinus Poulsen 1943, pp. 52-54, pi. 6, fig. 104. Spirifer contortus Barrande 1879, pi. 107, fig. ii. Spirifer davousti de Verneuil 1850, Bull. Soc. Geol. France, 2nd ser., 7, p. 781 (probably the same as togatoides). Spirifer devonicans Barrande 1879, pi. 4, fig. 19. Eospirifer eastoni Gill 1949, pp. 98-99, pi. 3, figs. 20, 21, 23. Eospirifer fusus Borisyak 1955, p. 72, pi. 12, fig. 10. Spirifer grandis Hedstrom 1923, pp. 10-11, pi. 2, figs. 5-9. Spirifer ( Eospirifer ) ignobilis Khodalevitch 1939, p. 109 (English), p. 66 (Russian), pi. 27, fig. 3. Spirifer insidiosus Barrande 1879, pi. 72, fig. iii. Spirifer lineatus J. de C. Sowerby 1825, Mineral Conchology , 5, p. 151, pi. 493, figs. 1-2. Spirifer marklini de Verneuil 1848, Bull. Soc. Geol. France, 2nd ser., 5, p. 344. Eospirifer parahentius Gill 1950, pp. 247-8, pi. 1, figs. 1-6. Spirifer plicatellus var. globosus Salter 1848, Mem. Geol. Surv. 11, i, p. 382. Eospirifer praesecans Havlfcek 1959, pp. 52-53, pi. 9, figs. 1-4, 6. Spirifer ( Eospirifer ) pseudoindijferens Nalivkin 1930, pp. 111-12, pi. viii, fig. 7. Eospirifer quinqueplicatus Poulsen 1934, pp. 18-19, pi. 2, figs. 17-19. Spirifer radiatus-obsoletus Foerste 1909 b, p. 14, pi. 2, fig. 10. Eospirifer subradiatus Wang 1956, pp. 577-8, pi. vii, c, figs. 1-2. Spirifer subsinuatus A. Romer 1855, Beitr. 3, p. 3, pi. 2, fig. 5. 688 PALAEONTOLOGY, VOLUME 5 Spirifer tenuistriatus Shaler 1869, Bull. Mus. Comp. Zool. 1, 4, p. 70. Spirifer togatoides Paeckelmann 1925, pp. 128-9, pi. 6, fig. la-e. Spirifer togatus Barrande 1848, Maid. Naturw. Abh. ii, pp. 167-8, pi. 15, fig. 2. Eospirifer tuvaensis Chernychev 1937, pp. 79-80, pi. v, figs. 18-21. Distribution. The distribution lists have been prepared to give complete geographic and stratigraphic coverage of the world; however, space does not permit including every reference from the literature for any given area. The following abbreviations are used: Sil. (Silurian), Dev. (Devonian), Lland. (Llandovery), Wen. (Wenlock), Lud. (Ludlow), Skal. (Skalian), Ged. (Gedinnian), Sieg. (Siegenian), Ems. (Emsian), Cobl. (Coblenzian), Eif. (Eifelian). In North America, widely distributed in strata of Upper Llandoverian to Ludlovian age: Northern Newfoundland: E. radiatus, Pike Arm fm., U. Lland. (C6) to Wen. (Shrock and Twenhofel 1938, p. 262). Northern Greenland: E. radiatus , E. consobrinus, E. quinqueplicatus, U. Lland. (C3 or younger) (Poulsen 1934, pp. 18-19; 1943, pp. 52-54). South-western Ontario: Eospirifer sp., De Cew fm., Wen. (Bolton 1957, p. 141). E. radiatus, ‘Ironde- quoit ’ fm., Rochester fnr., Ancaster chert of Goat Island member of Lockport fm., Wen. ; Wiarton member of Amabel fm., Guelph fm., Lud. (ibid., tables 7, 8, 10, 11, 12). Gaspe: E. radiatus. La Vieille fm., Wen., and West Point fm., Lud. (Northrop 1939, p. 190). Anticosti Island: E. radiatus, Jupiter fm., U. Lland. (C3 to C6), and Chicotte fm., Wen. (Twenhofel 1928, p. 219). Coastal New Brunswick: Eospirifer sp., Long Reach fm. and Mascarene series, U. Lland. (C6) to Wen. (identified by writer). Coastal Maine: E. radiatus, Eastport region, U. Lland., and Ames Knob fm., U. Lland. (C5) to Wen. (Beecher and Dodge 1892, p. 417). Northern Maine : E. cf. radiatus, Limestone Hill (Somerset Co.) and Chesuncook Is. (Piscataquis Co.), Wen. (identified by writer). E. radiatus, Aroostook Co., Wen. (Twenhofel 1941, p. 172; list prob- ably also includes collections from a Lud. horizon). Yukon: E. radiatus, unnamed beds, U. Lland. (C3 or younger) to Lud. (Kindle in Cairnes 1914, p. 73). New Hampshire: E. cf. radiatus, upper quartzite of Clough fm., U. Lland. (C4 to C6) (Boucot and Thompson 1958, pp. 362-3). Massachusetts: E. cf. radiatus, quartzite of Bernardston fm., U. Lland. (C3 or younger) to Lud. (Boucot, MacDonald, Milton, and Thompson 1958, pp. 860-1). New York: E. radiatus, U. Lland. (Irondequoit Is. [C5 to C6], Williamson sh., [C5 to C6], Wolcott Is. [C3 or younger], Reynales Is. [C3 or younger]), to Wen. (Rochester sh., Herkimer ss.) (Gillette 1947, p. 20). Unknown in Lud. strata in New York. Pennsylvania: E. radiatus, Clinton sh., U. Lland. (C3 or younger) to Wen. (Lesley 1890, p. 1028). Maryland: E. radiatus. Rose Hill fm., U. Lland. (C3 or younger), to Rochester fm., Wen. (Prouty and Swartz 1923, pp. 452-3). Indiana: E. radiatus, Waldron sh., Wen. (Hall and Clarke 1893, pi. 21, figs. 11-13, 26); Osgood fm., U. Lland. (C6) (Tillman 1961); Louisville Is., Wen. (Nettleroth 1889), pi. 29, figs. 13-16). Wisconsin: E. radiatus, Racine dolomite, Wen. (Hall and Clarke 1893, pi. 21, figs. 14-18). Oklahoma: Eospirifer sp., Clarita member of Chimneyhill fm., U. Lland. (C4) to Wen. (Arnsden 1957, p. 23). Arkansas: Eospirifer sp., St. Clair fm., U. Lland. (C3 or younger) to Lud. (Arnsden 1957, p. 23; Thomas 1926, p. 390-3). Kentucky: E. radiatus. West Union bed, U. Lland. (C3 or younger) (Foerste 19096, pp. 14-15). Ohio: E. radiatus, Massie Clay, Wen. (Foerste 1935, p. 153). Tennessee: E. foggi, Lobelville fm., Wen.; ‘Lego Is.’, U. Lland. (C3 or younger) to Wen. (Foerste 1935, pp. 172, 178, 197). State of Tamaulipas, Mexico: Eospirifer sp., vicinity of Ciudad Victoria (J. Carrillo, collections Ca 1689b, Ca 1684), U. Lland. (C3 or younger) to Lud. A. J. BOUCOT: THE EOSPIRIFERID AE 689 In Europe widely distributed in strata of Upper Llandoverian to Emsian age: Norway: E. marklini, Oslo region, L. Lland. (6c) (Kiaer 1908, p. 589). If it could be confirmed, this would be the earliest known eospiriferid occurrence, but after examining three specimens that presumably formed most of Kiaer’s material, this earliest reported occurrence appears dubious. One specimen, labelled ‘ Spirifer sp.’ (Pal. Mus. Oslo No. 52361), is the pedicle valve of a Strick- landia. The second, labelled ‘ Spirifer marklinV (Pal. Mus. Oslo, uncatalogued), is indeed Eospirifer marklini, but an old note with the specimen suggests that it came from Gotland rather than from Oslo. The third, labelled ‘ Spirifer marklini ’ (Pal. Mus. Oslo, uncatalogued), is also Eospirifer marklini, but again the locality is in serious doubt. Dr. Gunnar Henningsmoen, curator of the Palaeontological Museum in Oslo, writes (1961) regarding the two specimens of E. marklini : ‘As to the two other specimens, it is correct to say that their horizon is unknown, and their localities uncertain. They are thus no proof of a Lower Llandoverian occurrence of Eospirifer marklini.’’ Gotland: E. marklini, E. globosus, L. Yisby marl, U. Lland., to Slite group, Wen. (Hede 1921, p. 94). E. radiatus, U. Visby marl, U. Lland.; Hogklint Is., Slite group, Halla Is., Mulde marl, Wen. (Hede 1927«, p. 53; 19276, p. 51 ; 1936, p. 41 ; 1940, p. 66). Podolia : E. radiatus, Kitaygorod fm., U. Lland., and Borshchov fm., L. Ged. (Nikiforova 1954, p. 135). E. togatus, schistes marneaux a Strophomenides, Wen., to Schiste d’Onut, Ged. (Vascautanu 1931, p. 504, 532). Carnic Alps: E. togatus, Capolago, Ems. (Gortani 1915, pp. 130-2). Czechoslovakia : E. togatus, Tachlowitz, e2. Wen. or Lud. ; Konieprus, f2, and Mnienian, f2, L. Ems. (Barrande 1879, pi. 5, figs. 10-16). E. praesecans, L. Lud. and Wen. (Havlicek 1959, p. 53). E. contortus, Lud. (ibid., p. 56). E. togatus insidiosus, Koneprusy Is., L. Ems. (ibid., p. 43). E. devoni- cans, Kopanina beds, Lud. (ibid., p. 57). Harz Mts. : E. togatus, Kalk des Joachimskopfes, Ems. (Kayser 1878, p. 161). E. togatus var. subsinuata, Kalk des Schneckenberges und Badeholzes bei Magdesprung, Ems. (ibid., p. 162). Great Britain: E. radiatus, widely distributed in U. Lland, to early Lud. Urals: E. ignobilis, U. Marginalis beds, Ged. (Khodalevitch 1939, p. 109). E. cf. radiatus, Striatus beds, Lud. (ibid., pp. 67-68). Brittany: E. davousti, calcaire d’Erbray, Ems. (Barrois 1888, p. 145). Outside of Europe scattered occurrences in strata of Silurian to Middle Devonian age (unrecognized in South Africa and South America; its absence in South America is probably due to the almost total lack of information concerning shelly Silurian strata in that continent): Altai Mts.: E. pseudotogatus Khalfin 1948, Pseudotogatus horizon, concluded to be Sieg. (Khalfin 1948, p. 220). Kuznetsk Basin: E. secans, Baskukan beds, M. Dev. (Eif. or U. Ems.) (Rzonsnitskaya 1952, p. 35). Burma: E. cf. radiatus, Namhsim ss., Sil. (Reed 1906, pp. 108-9). New Zealand: E. togatus, Baton River beds, probable Ems. (Shirley 1938, pp. 476-9). Asia Minor: E. togatoides, Pendik Schichten (Bosphorus region), Ems. (Paeckelmann 1925, pp. 128-9). North Africa: E. togatus, Gisement du Kilometre 30 (Algeria), Sieg. (LeMaitre 1952, pp. 117-18). E. cf. togatus, French Morocco, L. Dev. (Termier 1936, p. 1144). E. radiatus, Morocco, Sil. (Gigout 1951, p. 45). Turkestan: E. togatus, Marginalis beds, Lud. (Nikiforova 19376, p. 49). E. davousti and E. pseudo- indifferens, highest Eif. (Nalivkin 1930, pp. 110-11). Kazahkstan: E. radiatus and E.fusus, U. Lland. (Borisyak 19556, pp. 70-72). China: E. subradiatus, Sil. (Wang 1956, pp. 577-8). Australia: E. eastoni, beds at Sandy’s Creek (Victoria), early Dev. (Gill 1949, pp. 98-99). Tasmania: E. parahentius. Bell Shale, Early Dev. (Gill 1950, pp. 247-8). Turkey: Eospirifer, Chamosite horizon near Cumakoy (NW. of Aquiran) in Istanbul region, U. Lland. Tuva: E. tuvaensis, Sil. (Chernychev 1937, pp. 79-80; pi. v; figs. 18-21). T'ien-Shan: Eospirifer sp., locality 14 of Arpishmebulag Series, Sil. and early Dev. (identified from photographs kindly provided by Prof. G. Regnell, Lund). 690 PALAEONTOLOGY, VOLUME 5 Genus macropleura gen. nov. Plate 98, figs. 1-8; plate 99, figs. 1-9; plate 100, figs. 1-5 Type species. Delthyris macropleurus Conrad 1840, 4th Ann. Rpt. New York Geol. Surv., p. 207. Diagnosis. Transversely elongate to elliptical eospiriferinids possessing a broad, flat fold and a limited number (usually three to six) of lateral plications on each flank, separated by broad, rounded interspaces. Comparison. Macropleura differs from Striispirifer and Nikiforovaena in that the latter two, although having a relatively broad fold, also have a large number of lateral plica- tions which are not separated from each other by broad interspaces. Eospirifer has flanks that are either smooth or faintly plicated anteriorly, never approaching the folded state attained by Macropleura. Macropleura lacks the anteriorly bifurcating plications which characterize Janius. Havlicekia has smooth flanks in large specimens, in contrast to the plicate condition of Macropleura. Exterior. Shells subequally biconvex (the brachial valve having a slightly greater degree of convexity), transversely elongate, and elliptical in outline. Maximum width extends from the straight hinge-line to about the midlength. Lateral margin relatively straight in posterior part, evenly curved in anterior part. Anterior margin evenly curved laterally, but straight medially. The brachial valve bears a broad fold with circular to rectangular cross-section. The fold rises from the descending anterior portion of the valve at an angle of about 20 degrees and first becomes prominent near the umbo. The pedicle valve has a corresponding sulcus. Lateral to the fold are three to four rounded costae on each flank, separated by broad, rounded interspaces of about the same width as the costae. Interarea of pedicle valve catacline to steeply apsacline, very long, concave posteriorly. Interarea of brachial valve orthocline, very short. Lateral margins of interarea striated by ornamentation identical with that on the body of the valve. Beak of pedicle valve suberect. Deltidial plates are usually not preserved, and the delthyrium, which encloses an angle of about 60 degrees, is left open. However, in well-preserved specimens a pair of narrow deltidial plates, normal to the interarea, line the sides of the delthyrium and are either apically conjunct or almost so. No specimens have been observed in which the delthyrium was completely covered. The observed specimens correspond to stages 1 and 2 of Beecher and Clarke (1889, p. 79, fig. 4), and no specimens have been observed that EXPLANATION OF PLATE 98 Figs. 1-5. Macropleura macropleura (Conrad, 1840). New Scotland formation; Helderbergs, New York, M.C.Z. No. 9259. 1. Brachial view (x 1). Note the fine striations. 2, Anterior view ( X 1 ). Note the broad, rounded fold and sulcus, and the weakly crenulated anterior commissure. 3, Posterior view ( X 1). Note the rounded lateral plications separated by broad, rounded interspaces. 4, Pedicle view (x 1). Note the relatively broad sulcus and the broad interspaces between the plica- tions. 5, Side view (x 1). Note the incurved, relatively short interarea of the pedicle valve. Figs. 6-8. Macropleura macropleura (Conrad, 1840). New Scotland formation; North American Cement Quarry, Alsen, New York. U.S.N.M. No. 137738, Zimm Collection, Acc. No. 167820. 6, Anterior view (x 1). Note the relatively rectangular cross-section of the fold and the crenulated anterior commissure. 7, Pedicle view (xl). Note the crenulated anterior and lateral margins. 8, Side view (x 1). Palaeontology, Vol. 5 PLATE 98 BOUCOT, Eospiriferidae A. J. BOUCOT: THE EOSPIRIFERID AE 691 approximate their stages 3, 4, and 5. The fine ornamentation consists of radiating fila which originate both by bifurcation and implantation and are crossed by concentric growth lamellae. A few of the concentric growth lamellae are very pronounced and frill- like, but the majority are mere lines whose intersections with the radial fine ornamenta- tion may become nodose in well-preserved specimens. Anterior commissure uniplicate and strongly crenulate. Anterior portion of pedicle valve projects up as a tongue to meet the fold of the brachial valve. Pedicle interior. Relatively small, pointed hinge teeth occur on the inner margin of the hinge line, where they are supported by plate-like dental lamellae which diverge from the midline at an angle of about 20 to 30 degrees. Dental lamellae convex medially, thickened in large specimens by the deposition of secondary material in the umbonal cavities and the delthyrial cavity. Muscle field triangular in outline, extending anteriorly about one-third of the distance to the anterior margin, bisected by low, rounded myo- phragm. On either side of myophragm are elongate, anteriorly expanding, longitudinally striate diductor impressions, which posteriorly surround the small, elliptical adductor impressions. In some specimens a thick pad of secondary material floors the rear of the delthyrial cavity and may have been the site of the pedicle callist. The sides of the upper portion of the delthyrial cavity are striated and bear a series of indentations that parallel the sides of the delthyrium and probably served to help seat the deltidial plates. The interior of the valve is strongly plicated by the impression of the external ornamentation. Brachial interior. The cardinalia consist of a narrow chamber that occupies the position of the cardinal process and is laterally flanked by discrete, inclined hinge-plates tilted basomedially. The hinge plates are supported basally by long crural plates. The floor of the dental sockets is relatively flat. A low myophragm extends from the notothyrial cavity to about midlength. The adductor field is not noticeably impressed. Species: Spirifer ( Eospirifer ) admirabilis Nikiforova 1937/; pars. p. 49, pi. 10, figs. 1, 2, 4, non fig. 3. Spirifer altaicus Tschernychev 1893, pp. 25-26, pi. 4, figs. 5-6. Eospirifer balchaaschensis Nikiforova 1 937a, pp. 26-27, pi. ii, figs. 6-7. Eospirifer? bascuscanicus Rzonsnitskaya 1952, p. 43, pi. i, fig. 12 (inspection of the holotype shows the presence of eospiriferid-type fine ornamentation). Spirifer perlamellosus J. Hall var. densilineata Chapman 1908, pp. 223-4, pis. iv-v. Spirifer eudora Hall 1861, Ann. Rpt. Wisconsin Geol. Surv., pp. 25-26. Spirifer geronticus Foerste 1909 a, p. 92, pi. 2, fig. 30. Spirifer gibbosus Hall 1861 non Barrande 1879, Ann. Rpt. Wisconsin Geol. Surv., p. 25. Delthyris macropleura Conrad 1840, 4th Ann. Rpt. New York Geol. Surv., p. 207. Spirifer macropleuroides Clarke 1907, Bull. 107, New York State Mus., p. 259. Spirifer niagarensis oligoptychus Roemer 1860, p. 68, pi. 5, fig. 8. Spirifer pollens Barrande 1848, Haid. Naturw. Abh. 2, pp. 182-3, pi. 17, fig. 6. Spirifer rollandi Barrois 1886, pp. 182-4, pi. v, fig. 1. Spirifer sibiricus Tschernychev 1893, pp. 24-25, pi. 4, fig. 4. Spirifer sinuosus Hedstrom 1923, pp. 12, 13, pi. 4, figs. 1-9. Spirifera striolata Lindstrom 1861, Ofversigt Kongl. Vetenskapsakad., Fork., Arg. 17 (1860), 8, p. 259, pi. 12, fig. 2. Spirifer telephus Barrande 1879, pi. 73. Spirifer uralaltaicus Gruenewaldt 1854, Mem. savants etrang. 7, pp. 32-34, pi. 6, fig. 20a-/. Spirifer vetulus Eichwald 1840, Lethaea Rossica, pp. 719-20, pi. 35, fig. 1. 692 PALAEONTOLOGY, VOLUME 5 Distribution. In North America widely distributed in strata of Wenlockian to Gedinnian age: South-east Alaska: A form resembling Macropleura (erroneously compared with J. irbitensis), Lud. (Kirk and Amsden 1951, p. 63; pi. 10, fig. 6). South-western Ontario: M. eudora, Lockport dolomite, Wen. (Williams 1919, p. 67). M. eudora, Wiarton, Eramosa, and Colpoy Bay members of Amabel fm., Guelph fm., Lud. (Bolton 1957, p. 58, 102; tables 11, 12). M. cf. eudora. Fossil Hill fm., U. Lland. (C5) to Wen. (ibid., table 9). Northern Maine: M. macropleuroides. Chapman sandstone (Aroostook Co.), Ged. (Clarke 1909, pp. 119-20). M. macropleura, Somerset Co., Ged. (Boucot, in preparation), and Aroostook Co. (Square Lake Is.), Ged. (Billings 1869, pi. 1, fig. 16). New York: M. macropleura. New Scotland fm. (Helderbergs and Green Pond outlier), Ged. Maryland and West Virginia: M. eudora. Rose Hill fm., U. Lland. (C3 or younger), to Rochester fm., Wen. (Prouty and Swartz 1923, pp. 453-4). M. macropleura. New Scotland member, Ged. (Schu- chert 1913, p. 396). Western Tennessee: M. macropleura, Birdsong fm., Ged. (Dunbar 1919, p. 53). M. niagarensis oligo- ptychus, Brownsport fm., Wen. (Roemer 1860, p. 68). Virginia: M. macropleura. New Scotland Is., Ged. (Butts 1940, pp. 265, 278). New Jersey: M. macropleura, Coeymans Is., Ged. (Weller 1903, pp. 288, 313). Ohio: M. eudora, West Union bed, U. Lland. (C3 or younger) (Foerste 1909fi, p. 16). Wisconsin: M. eudora, Racine dolomite, Wen. (Hall and Clarke 1893, pi. 21, figs. 19-20). Indiana: M. eudora, Waldron shale (Hall and Clarke 1893, pi. 21, figs. 21, 29); and Osgood fm., U. Lland. (C5 to C6) (Tillman 1961). Pennsylvania : M. eudora, ‘ Niagara fm.’, Sil., and M. macropleura, New Scotland equivalents — ‘ Storm- ville shales’ and ‘Stormville Is.’, Ged. (Lesley 1990, pp. 1010, 1016). EXPLANATION OF PLATE 99 Figs. 1, 2. Macropleura macropleura (Conrad, 1840). New Scotland formation; North American Cement Quarry, Alsen, New York. U.S.N.M. No. 137738, Zimm. Collection, Acc. No. 167820. 1, Brachial view ( x 1). Note the fine striations and the beaded effect due to the intersection of fine, concentric growth-lines and radial striae. 2, Posterior view (x 1). Note the relatively long interarea of the pedicle valve. Figs. 3, 4. Macropleura macropleura (Conrad, 1840). New Scotland formation; Clarksville, Albany County, New York. M.C.Z. No. 9427. 3, Impression of interior of pedicle valve (x 1-5). Note the impression of the broad, rounded lateral plications. 4, Impression of the interior (posterior view X I -5). Note the presence of narrow crural plates. Fig. 5. Macropleura macropleura (Conrad, 1840). Birdsong shale; just south of Camden, Tennessee. U.S.N.M. No. 137729. Interior of pedicle valve (x 1). Note the stout dental lamellae, the secondary material deposited in the umbonal cavities, and the pitting of the floor of the valve in the umbonal region. Fig. 6. Macropleura eudora (Hal), 1861). Waldron shale; Locality 521a, Quarry on south side of U.S. 70, 2 miles east of Pegram Station, Tennessee. U.S.N.M. No. 137730. Posterior view (x 3). Note the narrow deltidial plates bordering the delthyrium and inserted normal to the interarea. The fine, beaded ornamentation is formed from the intersection of fine concentric growth lamellae and radial striae. Figs. 7, 8. Macropleura macropleura (Conrad, 1840). New Scotland formation; locality 526, U.S. 40, east bank of Licking Creek, 2\ miles west of Indian Springs, Maryland. U.S.N.M. No. 126051. 7, Interior of brachial valve (x2). Note the relatively long, slender crural plates supporting the discrete hinge-plates, and the laterally directed dental sockets. 8, Interior of brachial valve (x2). Note the unstriated area of diductor attachment. Fig. 9. Macropleura macropleura (Conrad, 1840). Shale of New Scotland age; Cornwall, Orange County, New York. U.S.N.M. No. 17164. Impression of interior of pedicle valve (x 1). Note the massive dental lamellae. Palaeontology, Vol. 5 PLATE 99 l-V-' WmM mml tsfm- t “ uki" ' -h BOUCOT, Eospiriferidae A. J. BOUCOT: THE EOSPIRIFERIDAE 693 In Europe known from strata of Upper Llandoverian to Emsian age: Czechoslovakia: M. telephus, Collines entre Luzetz et Lodenitz (e2), Wen. (Barrande 1879, pi. 4, fig. 6). M. pollens, same locality. Wen. (ibid., pi. 1, fig. 16). Havlicek (1959, p. 52) cites this locality as of Lower Ludlow (Kopanina) age. Gotland: M. striolata. Eke marl and Hamra Is. Lud. or possibly Ged. (Hede 1921, p. 94). M. sinuosa, Slite group. Wen. (ibid., 19276, p. 51 ; 1928, p. 63; 1933, p. 57; 1936, p. 41 ; 1940, p. 66). Urals: M. exsul (without anteriorly bifurcating ribs like /. ex.su/ of Barrande). Striatus beds, Lud. (Khodalevitch 1939, p. 68, pi. 27, fig. 6). France: M. thetidis Le Maitre non Barrande, Calcaire de Chaudefonds, Ems. (LeMaitre 1934, p. 73). M. ro/landi, same Is. (Barrois 1886, p. 182-4). Outside of Europe and eastern North America recognized only in Asia and Australia: Mongolia: Chernychev (1937, p. 79, pi. v, figs. 22-23) illustrates Silurian material (‘ Eospirifer aff. radiatus') that belongs to Macrop/ewci. Altai Mts. : M. sibiricus, light grey Is. of Krjukowski Grube, and M. ciltaicus, reddish Is. of same place, Eif., together with ‘ Goniatites' I ateseptatus Beyrich (Tschernychev 1893, pp. 24-26). Kuznetsk Basin: M. sibiricus, Chumishsk beds, Eif.; M. bascuscanicus, Pesterevo beds, Cobh; M. cf. rollcmdi, Salairkin beds, Eif. (Rzonsnitskaya 1952, pp. 41-43). Turkestan and western Balkhash Land: M. balchaaschensis, Marginalis beds, Ged. (Nikiforova 1937 b, pp. 48-49). M. admirabilis Nikiforova 1937 pars (pi. 10, figs. 1, 2, 4, non 3), Manak beds, Ged. Kazakhstan: E. radiatus Borisyak non Sowerby, Wen. (Borisyak 1955a, pp. 54-55, pi. 8, figs. 1-6). Borisyak (1960, p. 270) emends the age to Lud. Kolyma River headwaters: M. vetulus, Taskwan River, Sil. (Nalivkin 1936, p. 23, pi. ii, fig. 6). Rzon- snitskaya (1960, oral communication) states that this locality is U. Ems. or L. Eif. Australia: M. densilineata, Sil. or L. Dev. (Chapman 1908, pp. 223-4). Genus havlicekia gen. nov. Plate 103, figs. 12-17 Type species. Spirifer secans Barrande 1848, Haid. Naturw. Abb. II, pp. 168-9, pi. xvi, fig. 6. Name. The genus is named in recognition of the major contributions of Dr. Vladimir Havlicek, to knowledge of Lower Palaeozoic brachiopods. Diagnosis. Eospiriferinids with striispiriferid-type plications in the early growth stages, smooth flanks during the later growth stages, and an acuminate form during the later growth stages, together with a very high tongue at the anterior margin of the pedicle valve which produces a very extended, uniplicate anterior margin. Comparison. Havlicekia lacks, in the later growth stages, the lateral plications present in Striispirifer, Macropleura , and Nikiforovaena. The acuminate form and abnormally shaped, uniplicate anterior margin are unique among the eospiriferinids. Pedicle exterior. Valve strongly convex, laterally ellipsoidal in outline, maximum width slightly anterior of posterior margin. Interarea catacline, straight, posteriorly concave. The delthyrium encloses an angle of about 60 degrees. The beak may be relatively straight or strongly incurved. The deltidial structures have not yet been distinguished, but are presumably similar to those present in other members of the subfamily. In the early growth stages (up to about 1-1 1 cm. long) the shell bears striispiriferid-type lateral plications on the flanks, but these plications disappear beyond this early stage. The fine ornamentation consists of radial fila. Lateral margins rounded; anterior margin uni- plicate and abnormally high in large specimens as a result of the acuminate form of the 694 PALAEONTOLOGY, VOLUME 5 large shells compared with the non-acuminate form of the early growth stages. The anterior portion of the valve projects up as a long tongue. Brachial exterior. Valve gently convex in early growth stages, strongly convex (about equal to that of pedicle valve) in large specimens. Interarea orthoclineto gently apsacline, very short as compared with that of pedicle valve, and strongly incurved over that of pedicle valve. In large specimens the fold is very high anteriorly with vertical sides and U-shaped cross-section. The tremendous change in form accompanying the develop- ment of an anterior tongue in the pedicle valve and the steep-sided fold in the brachial valve is well documented by Havlicek (1959, fig. 7). Pedicle interior. Two strong dental plates, about one-third the length of the shell, border the delthyrium and support the stubby hinge teeth. Almost no secondary material is deposited around the plates except for a small amount in the apex of the valve and the extremities of the umbonal cavities. The dental lamellae diverge from the midline at an angle of about 20 to 30 degrees. The muscle field extends about one-third of the distance to the anterior margin and is very poorly impressed except for a low myophragm. The myophragm is laterally bounded by anteriorly expanding diductor impressions which are longitudinally striate and posteriorly enclose the small, elliptical adductor impres- sions. Anterior and lateral periphery of valve smooth, umbonal regions crenulated by impress of external plications. EXPLANATION OF PLATE 100 Figs. 1-5. Macropleura eudora (Hall, 1861). Waldron shale; Dupont, Indiana. U.S.N.M. No. 88008. 1, Side view (x 1). Note the incurved beak of the pedicle valve. 2, Pedicle view (x 1). Note the broad sulcus. 3, Posterior view (xl). Note the relatively short interarea of the pedicle valve. 4, Brachial view (xl). Note the broad, rounded interspaces between the lateral plications. 5, Anterior view (xl). Note the crenulated anterior commissure. Fig. 6. Striispirifer niagarensis (Conrad, 1842). Clinton shale; Lockport, New York. U.S.N.M. No. 126048. Impression of interior of brachial valve ( X 1). Note the relatively long crural plates and the unstriated area of diductor attachment. Fig. 7. Striispirifer niagarensis (Conrad, 1842). Racine dolomite; Wauwatosa Wisconsin. U.S.N.M. No. 137731. Impression of interior (posterior view, X2). Note the long, slender crural plates and the unstriated area of diductor attachment. Fig. 8. Striispirifer plicatella (Linnaeus, 1767). Wenlock limestone; Dudley, England. U.S.N.M. No. 99946. Posterior view ( x 3). Note the narrow deltidial plates bordering the delthyrial cavity and inserted normal to the interarea. Figs. 9-13. Striispirifer niagarensis (Conrad, 1842). Clinton group; Lockport, New York. U.S.N.M. No. 3900. 9, Side view (x2). Note the slightly incurved beak of the pedicle valve. 10, Posterior view ( x 2). 11, Anterior view ( X 2). Note the rounded cross-section of the fold and sulcus, and the crenulated anterior commissure. 12, Brachial view (x2). Note the narrow interspaces between the lateral plications. 13, Pedicle view ( x 2). Note the broad sulcus and the narrow interspaces between the lateral plications. Fig. 14. Striispirifer plicatella (Linnaeus, 1767). Mulde marl; Djupviks fisklage, Eksta, Gotland. M.C.Z. No. 2803. Preparation of spire (x2). Note the short jugal process, and the obtuse angle included between the crura and the primary lamella. Fig. 15. Striispirifer plicatella (Linnaeus, 1767). Strata of Silurian age; Gotland. M.C.Z. No. 2075. Preparation of spire (x 2). Note the short jugal process, and the obtuse angle included between the crura and the primary lamella. Palaeontology, Vol. 5 PLATE 100 BOUCOT, Eospiriferidae r A. J. BOUCOT: THE EOSPIRIFERIDAE 695 Brachial interior. The cardinalia consist of discrete hinge-plates supported medially by long crural plates. Dental sockets closed postero-laterally, flared antero-laterally. Area of diductor attachment smooth. A low myophragm about one-third the length of the valve bisects the feebly impressed muscle field. Anterior and lateral margins smooth, umbonal regions crenulated by impress of external plications. Species: Spirifer secans Barrande 1848, op. cit. Spirifer ( Eospirifer ) secans var. rants Khodalevitch 1951, p. 97, pi. 30, fig. 2. Spirifer turjensis Tschernychev 1893, Mem. Com. Geol. 4, 3, pp. 170-1. Distribution. Widely distributed in the Old World; but only a single specimen known in the New World: Czechoslovakia: H. secans, Koneprusy Is., L. Ems. (Havllcek 1959, p. 41). H. turjensis, Pridoli Is., Skal. (ibid., p. 49). Carnic Alps: H. secans, Capolago, Ems. (Gortani 1915, pp. 130-2). Kuznetsk Basin: H. secans, Baskuskan beds, U. Ems. or Eif. (Rzonsnitskaya 1952, p. 35). New Zealand: H. secans. Baton River beds, probably Ged. (Shirley 1938, pp. 476-9). North Africa: H. secans, L’Erg Djemel (Algeria), Ems. (LeMaitre 1952 , pp. 117-18). Urals: H. turjensis. Wen. (Khodalevitch 1939, pp. 65-66). H. secans var. rarus Gobi. (ibid. 1951, p. 97). H. turjensis, L. Dev. (ibid. 1937, p. 67). Germany: H. secans, Erbsloch graywacke L. Ems. (Assmann 1910, p. 152 pi. 8 fig. 13). Indiana : H. cf. secans, Huntingdon dolomite Lud. (identified by writer in collections of Indiana Uni- versity from ‘N. Bluff 1/2 mi. E. of Georgetown ’)• Genus striispirifer Cooper and Muir-Wood 1951 Plage 100, figs. 6-15 Type species. Delthyris niagarensis Conrad 1842, J. Acad. Nat. Sci. Philadelphia, 8, p. 261. Diagnosis. Eospiriferinids having an unplicated fold and sulcus laterally bordered by numerous costae separated from each other by narrow, V-shaped interspaces. Comparison. Striispirifer lacks the anteriorly bifurcating costae of Janius, the broad U-shaped interspaces of Macropleura, the unplicated flanks of Eospirifer, and the plicate fold and sulcus of Nikiforovaena. Exterior. Shells impunctate, subcircular to laterally elongate, with a spiriferiform shape. The pedicle valve is about two to three times as deep as the gently convex brachial valve. Hinge-line straight, almost equal in length to the maximum length, which is situated about one-third of the distance to the anterior margin. Lateral extremities evenly rounded to alate, anterior margin evenly rounded, crenulate, and plicate. Interarea of pedicle valve apsacline and concave posteriorly, interarea of brachial valve anacline. Interarea of pedicle valve about three to four times the length of that of the brachial valve. The interareas bear growth-lines paralleling the hinge-line. The delthyrium includes an angle of about 60 degrees and may be bordered by discrete deltidial plates, medially conjunct deltidial plates which include a pedicle foramen, or a pseudodeltidium- like structure formed by the deposition of secondary material as illustrated by Hall and Clarke (1893, p. 21, fig. 4; pi. 37, fig. 1) and Beecher and Clarke (1889, pi. 6, fig. 8). Coarse ornamention consists of radial costae separated from each other by narrow, 696 PALAEONTOLOGY, VOLUME 5 V-shaped interspaces. Large shells carry up to fifteen costae on each side of the fold, which is about five times as wide as the first lateral costa, low, and implicated, with circular to subrectangular cross-section. Fine ornamentation consists of radial fila intersected by fine growth lamellae. Pedicle interior. Dental lamellae well developed, blade-like, and unthickened by secondary material except in the apices of the umbonal and delthyrial cavities. The short, stubby hinge teeth, situated on the inner side of the hinge-line, are supported by the dental lamellae. A low myophragm bisects the muscle field, which extends laterally about one-third of the length of the valve. Periphery and most of the interior crenulated by the impress of the costae. Musculature similar to that of Macropleura and Eospirifer. Brachial interior. Similar to that of the other eospiriferinids except where the impress of the costae reflects the outer character of the shell. Relatively long crural plates sup- port discrete hinge-plates. Area of diductor attachment smooth. A low myophragm bisects the muscle field. The crura make an obtuse angle with the primary lamellae. The short jugal process descends toward the pedicle valve near the junction of the crura and primary lamella. Species: Spirifer foggi Nettleroth 1889, p. 117, pi. 32, figs. 28-31. Spirifer interlineatus Sowerby 1839, Sit. Syst., pi. 12, fig. 6. Delthyris niagarensis Conrad 1842, ./. Acad. Nat. Sci. Philadelphia, 8, p. 261. Anomia plicatella Linnaeus 1767, Syst. Nat., 12th ed., p. 1154. Spirifer repertus Foerste 19096, p. 16, pi. 1, fig. 14a-6; pi. 2, fig. 5. Eospirifer stonehousensis McLearn 1924, pp. 84-85, pi. 9, fig. 8. Spirifer (. Eospirifer ) subviator Khodalevitch 1951, p. 99, pi. 29, figs. 1-2. Spirifer tenuis Barrande 1879, pi. 138, fig. ix. Spirifer viator Barrande 1848, Haul. Naturw. Abh., 2, p. 181, pi. 15, fig. 3. Species to he investigated: Delthyris cyrtaena Dalnran 1828, K. Vetensk. Hand/., 1827, p. 120, pi. 3, fig. 3. Distribution. In eastern North America widely distributed in strata of Upper Llan- doverian to Ludlovian age: Nova Scotia: S. stonehousensis, French River fm., Pictou Co. Maehl, 1961, (p. 52), U. Lland. (C3 or younger). S. stonehousensis is also listed by McLearn (1924, p. 84) from a boulder that he believed came from the Stonehouse fm., of L. Ged. (Podolella and Proschizophoria occur in the top of the fm. near Pictou at one of Maehl’s localities) and possible Lud. age, but the writer concludes that McLearn’s boulder came from the French River fm. Gaspe: Striispirifer cf. niagarensis, St. Leon fm., early Lud. (Alcock 1935, p. 50). If the material is correctly identified, it represents the only member of the genus thus far recognized in Gaspe. South-western Ontario : S. niagarensis, ‘ Irondequoit ’ dolomite member and Rochester shale fm.. Wen. ; Lockport dolomite, Wen. (Williams 1919, pp. 51, 55, 67). S. niagarensis, ‘Reynales’ fm., ‘Ironde- quoit’ fm., Rochester fm., Ancaster chert of Goat Island member of Lockport fm., Lockport fm., Wen.; Wiarton member of Amabel fm., Wen. and Lud. (Bolton 1957, pp. 27, 31, 48, 85, 94, 109, 126, 130, 137, 139, tables 7, 8, 10, 11). New York: S. niagarensis, Irondequoit Is., U. Lland. (C5 to C6), to Rochester shale and Herkimer ss.. Wen. (Gillette 1947, p. 20). Maryland: S. niagarensis, Rochester fm., Wen. (Prouty and Swartz 1923, p. 455). Ohio: S. niagarensis and S. plicatellus, Dayton Is. U. Lland. (C5 or younger) (Foerste 1935, p. 151). A. J. BOUCOT: THE EOSPIRIFERIDAE 697 Kentucky: S. foggi, Niagara group, Lud. (Nettleroth 1889, pp. 117-19). Indiana: S. foggi, Liston Creek reef, Lud. (Cummings 1930, p. 209). S. niagarensis, Osgood fm. and Laurel Is., U. Lland. (C5 to C6) (Tillman 1961). Pennsylvania: S. niagarensis, ‘Clinton fossil ore’, Sil. (Lesley 1890, p. 1024). Iii Europe widely distributed in strata of Silurian and Devonian age: Podolia: S. interlineatus, Kitaygorod fm., U. Lland (Nikiforova 1954, p. 136). England: S. interlineatus, Wenlock shale and Is., Wen., and Aymestry Is., Lud. (Davidson 1871, pi. 9, figs. 9-12). Czechoslovakia: S. viator, Collines entre Luzetz et Lodenitz (e2), Dlauha Hora (e2), Wohrada (e2), Listice (e2), Rochers de Kozel (e2); Wen. or Lud. (Barrande 1879, pi. 7, figs. 4-1 1 ; pi. 73, fig. iii, 1-8; pi. 138, fig. 9). S. tenuis, Liten to Lochkov beds, Wen. to Ged. (Havlicek 1959, p. 60). Gotland: S. interlineatus (Hedstrom non Sowerby), Slite group, Wen. (Hede 19276, p. 51; 1933, p. 57; 1936, p. 41 ; 1940, p. 65). S. cf. interlineatus (Sowerby) Hemse group, L. Lud. (ibid. 1927o, p. 53). Norway: S. plicatella, Oslo region, U. Lland. (7c) and Wen. (8a, b, c) (Kiaer 1908, p. 589). Estonia: S. cf. interlineatus Hedstrom, Jaagarahu-Kalkstein, Wen. (Luha 1930, p. 9). Urals: Spirifer ( Eospirifer ) subviator, L. Dev. to Eif. (Khodalevitch 1951, p. 99). Genus nikiforovaena gen. nov. Plate 103, figs. 1-6 Type species. Spirifer ( Eospirifer ) ferganensis Nikiforova 19376, p. 48 (Russian text); pp. 80-81 (English text); pi. 10, figs. 5 a-d, 6a-b. Name. The genus is named in recognition of Dr. Olga Nikiforova’s major contributions to knowledge of Lower Palaeozoic brachiopods. Diagnosis. Transversely elongate to elliptical eospiriferids with flanks ornamented by gently rounded costae separated by U-shaped interspaces, and with one or more prominent median grooves on the fold and corresponding plication or plications in the sulcus. Comparison. Nikiforovaena has the lateral costae of Macropleura, with the addition of a groove or grooves on the fold and corresponding plication or plications in the sulcus. No other eospiriferid has this type of lateral costae combined with a grooved fold and a plicated sulcus. Exterior. Shells elliptical in outline, laterally elongate, unequally biconvex, the pedicle valve being about one and a half times as deep as the brachial valve. Hinge-line straight, equal to maximum width. Lateral and anterior margins evenly rounded. Anterior com- missure uniplicate and crenulate. Interarea striated by growth-lines paralleling hinge- line. Interarea of pedicle valve apsacline, posteriorly concave, about three to four times as long as that of brachial valve. Interarea of brachial valve anacline. Coarse ornamenta- tion consists of costae with rounded cross-sections, separated by U-shaped interspaces on the flanks, a deep median groove or grooves on the fold, and a sharp median plica- tion or plications in the sulcus. The tongue of the sulcus is serrated terminally by the junction of the median plication and the groove. Each flank bears about four to eight plications. Fine ornamentation consists of radial striae crossed by fine concentric growth- lines to give a reticulate effect. Delthyrium open, includes an angle of about 60 degrees. Narrow delthyrial plates may be present. 698 PALAEONTOLOGY, VOLUME 5 Pedicle interior. The interior of the pedicle valve has two prominent dental lamellae. Brachial interior. No information available. Species: Spirifer ( Eospirifer ) admirabilis Nikiforova 19376, p. 49 (Russian text), pi. 10, fig. 3, non figs. 1, 2, 4. Spiriter bowningensis Mitchell 1921, pp. 545-6, pi. 21, figs. 21-22. Spirifer {Eospirifer) ferganensis Nikiforova 19376, p. 48 (Russian text); pp. 80-81 (English text); pi. 10, figs. 5 a-d, 6a-b. Spirifer lynxoides Nalivkin 1926, Sketch of Turkestan Geology, p. 34 (first figured by Nikiforova 19376, p. 80, pi. 10, figs, la-c, 8-11). Spirifer ( Eospirifer ) tingi Grabau 1926, pp. 37-43, pi. 2, figs. 16-21. Distribution: Australia: N. bowningensis. Lower and Middle Trilobite beds, Wen. or Lud. (Mitchell 1921, p. 546). Japan: N. tingi. Stage G2 of the Gion-Yama Series (Kuma-Kii), Wen. or Lud. (Hamada 1961, p. 29). China: N. tingi, Miaokao group (eastern Yunnan), Lud. (Grabau 1926, pp. 18-19). Turkestan: N. ferganensis and N. lynxoides, Marginalis and Isfara beds, Lud. (Nikiforova 19376, p. 48, 50, 80). N. admirabilis, Ged. (ibid., p. 49, pi. 10, fig. 3, non figs. 1, 2, 4). Genus janius Havlicek 1957 Plate 101, figs. 1-13; plate 103, figs. 7-11; plate 104, figs. 9-14 Type species. Spirifer nobilis Barrande 1848, Haid. Naturw. Abh. 2, p. 32, pi. 18, fig. 2. Diagnosis. Eospiriferids with anteriorly bifurcating costae. The fold and sulcus may or may not be costate. Comparison. Janius can be distinguished from all other members of the Eospirifennae because it has anteriorly bifurcating costae on the flanks. Exterior. Shells transversely elongate, elliptical in outline, unequally biconvex, with brachial valve gently convex and pedicle valve subpyramidal. The brachial valve bears a fold which is subrectangular in cross-section; the pedicle valve has a corresponding sulcus. Hinge-line straight, almost as wide as the maximum width, which is located near the midlength. Interarea of pedicle valve steeply apsacline, concave posteriorly, about live to seven times longer than that of brachial valve. Interarea of brachial valve gently apsacline. Lateral margins of interarea striate, but remainder smooth except for growth- lines which parallel the hinge-line. Lateral margins and lateral portion of anterior margin evenly rounded, but median portion of the anterior margin almost straight. Anterior commissure uniplicate and crenulate. Delthyrial cavity bordered by narrow deltidial plates which are apically conjunct and resemble those figured by Beecher and Clarke (1889, p. 79, fig. 4, no. 3). Coarse ornamentation consists of three to five costae on each flank. In some species two costae are present on the fold and one or two in the sulcus. The costae on the flanks bifurcate anteriorly. Costae rounded in cross-section, separated by U-shaped interspaces of about same width and curvature as costae. Fine ornamentation consists of radial fila and fine concentric growth-lines. The fila increase both by implantation and bifurcation. The junctions of the concentric and radial fine ornamentations are nodose in well-preserved specimens. A few prominent concentric growth-lines are present. A. J. BOUCOT: THE EOSPIRIFERIDAE 699 Pedicle interior. Relatively small hinge teeth at medial ends of the hinge-line are sup- ported by long dental lamellae. Dental lamellae convex medially, include an angle of about 30 degrees. On the specimens studied, the muscle field is poorly impressed; it consists of diductor impressions which expand anteriorly, are separated by a low median myophragm, and posteriorly include a small pair of elongate, feebly impressed adductor impressions. Interior crenulated by impress of external ornamentation. Brachial interior. The cardinalia consist of a small chamber (occupying the position of the cardinal process) laterally bounded by long crural plates which support the discrete hinge-plates. The hinge-plates floor the dental sockets. A low myophragm bisects the area of muscle attachment, which is very feebly impressed and appears to consist of a pair of elongate adductor impressions extending to a position just short of the mid- length. Interior strongly impressed by external coarse ornamentation. The ribbon-like crura make an oblique angle with the primary lamellae. No jugal processes were found in the three specimens of J. schmidti studied. Geologic range. Highest Wenlockian (zones of Cyrtograptus radians and Monograptus testis in Bohemia) to Eifelian. Species: Spirifer exsul Barrande 1848, Haid. Naturw. Abh. 2, p. 184, pi. 15, fig. 5. Spirifer inconstans Hall 1862, Rpt. Wisconsin Geol. Snrv., p. 26, 1, 1, 1867, p. 436, pi. 69, fig. 6. Spirifer insignis Hedstrom 1923, pp. 13-15, pi. 5, figs. 1-24. Spirifer nobilis Barrande 1848, Haid. Naturw. Abh. 2, pp. 184-5, pi. 18, fig. 2. Spirifer nobilis var. fortiuscula Barrande 1879, pi. 7, fig. 12. Spirifer nobilis var. irbitensis Tschernychev 1893, Mem. Com. Geol. 4, 3, pp. 55-56, pi. 8 figs. 1-5. Spirifer racinensis McChesney 1861, New Paleozoic Fossils, p. 84; plates, 1865, pi. 8, figs. 3-3 b. Spirifer reluctans Barrande 1879, pi. 74, fig. ii (1-4). Spirifer rostellum Hall and Whitfield 1872, pp. 182-3. Spirifer schmidti Lindstrom 1861, Ofver. Vetenskapsakad., Arg. 17 (1860), 8, pp. 358-9, p. 12, fig. 1. Spirifer schmidti var. pyramidalis Wenjukow 1899, Mater. Geol. Russ., St. Petersburg, 19, pp .137-8, pi. 2, fig. 11. Eospirifer vetuloides Nalivkin 1960, pp. 382-3, pi. 89, figs. 1-2. Spirifer (. Eospirifer ) weberi Nalivkin 1930, pp. 112-13, pi. x, figs. 25-26. Distribution. In eastern North America widely distributed in strata of highest Wenlockian and Lower Ludlovian age: Gaspe: Eospirifer cf. eudora (resembles J. racinensis [McChesney]), Gascons fm. L. Lud. (Northrop 1939, p. 191; PL 101, fig. 10). New Brunswick: Janius cf. nobilis in association with Conchidium cf. knight i. Gambol Brook, Bathurst- Newcastle map-area (identification of J. cf. nobilis by the writer, of C. cf. knighti by Dr. L. M. Cumming) (PI. 103, figs. 20-22). Northern Maine: Janius sp., collections made by Dr. R. B. Neuman, U.S. Geol. Surv., on White Horse Lake, Shin Pond quadrangle, Penobscot County, L. Lud. (identifications by the writer; PI. 103, figs. 23-24). Illinois: J. nobilis, Chicago fm., Wen. and early Lud. (Hall and Clarke 1893, pi. 29, fig. 16). Wisconsin: J. nobilis, Racine dolomite, Wen. (Hall and Clarke 1893, pi. 37, figs. 2-3). 700 PALAEONTOLOGY, VOLUME 5 Indiana: J. tiobilis, Liston Creek reef, Lud. (Cummings 1930, p. 209). J. rostellum Louisville Is., Lud. (Hall and Whitfield 1872; 1875, pi. 9, figs. 11-13) (Nettleroth 1889, pi. 27, figs. 17-19; pi. 29, fig. 25). Alaska: J. nobilis, unnamed beds, U. Lland. (C3 or younger) to Lud. (Kindle 1908, p. 325). In Europe widely distributed in strata of highest Wenlockian to Ludlovian and possibly Lower Gedinnian age: Gotland: J. schmidti, Hemse group, L. Lud., and Eke group, Lud. or possibly slightly younger (Hede 1921, p. 94). (For a discussion of the age of the Eke group see Boucot 1960, p. 290.) /. insignis, Hemse group and Eke group, Lud. (Hedstrom 1923, p. 13). Podolia: J. schmidti, Malinovetski fm., Lud. (Nikiforova 1954, pp. 136-8; Vascautanu 1932, p. 509). J. pyramidalis, Malinovetski fm., Lud. (Nikiforova 1954, pp. 138-9), and Skal. (Vascautanu 1932, p. 463). Novaya Zemlya: J. irbitensis, Kostin Shar, Lud. (Alferov 1937, p. 10). /. vetuloides, U. Eif. (Nalivkin 1960, p. 383). England: J. cf. nobilis, L. Lud. (this paper, PI. 101, fig- 10). Janius Wenlock Is., Wen. (this paper, PI. 101 , fig. 9). Czechoslovakia: J. nobilis, Collines entre Luzetz et Lodenitz (e2). Wen. or Lud. (Barrande 1879, pi. 7, figs. 13-15). J. cxsul Barrande, Kopanina beds, Lud. (Havlicek 1959, pi. k2, figs. 1-5). J. reluctans, Listice (e2). Wen. or Lud. (Barrande 1879, pi. 74, fig. ii, la, 4; Havlicek 1959, p. 62, concludes that /. reluctans is the young of J. exsul). J. exsul, Lodenitz (e2) and Collines entre Luzetz et Bubowitz (e2), Wen. or Lud. (ibid., pi. 1, figs. 1, 2; pi. 76, fig. 2). EXPLANATION OF PLATE 101 Figs. 1-6. Janius schmidti (Lindstrom, 1861). Probably from the Eke Group; Gotland (probably from Lau backar, Lau parish, Ronehamn map sheet). U.S.N.M. No. 126057. 1, Pedicle view (xl). Note the plications in the sulcus and the bifurcating lateral plications. 2, Brachial view (x 1). Note the presence of anteriorly bifurcating lateral plications and bifurcating plications on the fold. 3, Side view (x 1). Note the relatively long interarea of the pedicle valve. 4, Anterior view (x 1). Note the crenulated anterior commissure. 5, Posterior view (x 1). Note the narrow deltidial plates bordering the delthyrial cavity and inserted normal to the interarea. 6, Exterior of pedicle valve ( X 3). Note the beaded fine ornamentation formed by the intersection of the concentric growth lamellae and the radial striae. Figs. 7, 8. Janius cf. schmidti (Lindstrom, 1861). Racine dolomite; Racine, Wisconsin. U.S.N.M. No. 126053. 7, Posterior view of impression of interior ( X 1). Note the relatively long crural plates and the unstriated area of diductor attachment. 8, Brachial view of impression of interior (:< 1). Note the presence of anteriorly bifurcating lateral plications and bifurcating plications on the fold. Fig. 9. Janius cf. nobilis (Barrande, 1848). Wenlock limestone; old quarry at Iron Bridge, in Benthall Wood, Grid Ref. 665/034, map sheet 118 (Shrewsbury). Boucot loc. 56GB170, U.S.N.M. No. 137739. Pedicle view (x 1). Note the unplicated sulcus and the anteriorly bifurcating lateral plica- tions. Fig. 10. Janius cf. nobilis (Barrande, 1848). Lower Ludlow; Old quarry, 250 yards WNW. of mile- stone (1 mile to Hundred House) and 1 mile S. 39° E. of Church, Abberley, Worcs., G.B. Geo- logical Survey Collection No. Gr.-249. Rubber replica (x 1) of brachial valve exterior. Note the unplicated fold and the presence of anteriorly bifurcating lateral plications. Fig. 11. Janius cf. nobilis (Barrande, 1848). Upper Gascons formation; Black Cape, Quebec. Pea- body Museum, Yale Univ. No. 2850/6. Brachial view (x H). Note the anteriorly bifurcating medial plication. Figs. 12, 13. Janius schmidti (Lindstrom, 1861). Eke Group; Lau backar, Lau parish, Ronehamn map sheet, Gotland. 12, Preparation of spire (x2). Note the absence of a jugal process, and the obtuse angle included by the crura and primary lamella. U.S.N.M. No. 137732. 13, Impression of interior (posterior view, X 3). Note the relatively long crural plates and the unstriated area of diductor attachment. U.S.N.M. No. 137733. Palaeontology, Vol. 5 PLATE 101 10 5 BOUCOT, Eospiriferidae A. J. BOUCOT: THE EOSPIRIFERIDAE 701 Urals: /. irbitensis, Striatus beds, L. Lud., and Marginalis beds, U. Lud. (Khodalevitch 1939, pp. 64- 65); L. Dev. (ibid. 1937, p. 67). Estonia: J. schmidti, Lud. (Schmidt 1881, p. 49). Outside of Europe and eastern North America recognized only in central Asia: Turkestan: /. irbitensis, Marginalis beds and possibly Isfara beds, bed. and Lud. ? (Nikiforova 1937, p. 50). J. irbitensis, Eif. (Nalivkin 1930, pp. 108-9), together with J. weberi (ibid., pp. 112-1 3) and J. vetulus (ibid., p. 107). Kuznetsk Basin: J. ex. gr. nobilis, Salairkin beds, Eif. (Rzonsnitskaya 1952, p. 39). Subfamily cyrtiinae Fredericks 1924 Diagnosis. The subfamily Cyrtiinae is redefined to include those members of the Eospiriferidae having a pyramidal pedicle valve, a catacline to steeply procline pedicle interarea, and an elongate delthyrium occupied by a complex deltidium. The brachial valve has chilidial plates or a chilidium. Genera: Cyrtia Dalman 1828, K. Vetenskapsakad. HandLf 1827, pp. 92, 93, 97. Plicocyrtia Boucot gen. nov. Geological range. Upper Llandoverian to Eifelian. Geographical range. Europe, eastern North America, Tasmania, and possibly Turkestan if C.? aff. petasus (Nikiforova 1937, p. 51) belongs to Plicocyrtia. Genus cyrtia Dalman 1828 Plate 102, figs. 1-5, 12-17; Plate 104, figs. 4-8 Type species. Anomites exporrectus Wahlenberg 1821, Nova Acta Reg. Soc. Sci. Uppsaliensis, 8, p. 64, no. 3. Diagnosis. Cyrtia is characterized by unplicated flanks and an unplicated fold and sulcus. Comparison. Cyrtia may be distinguished from Plicocyrtia by the absence of plicated flanks. Pedicle exterior. Valve pyramidal, in outline subcircular to laterally elongate or even alate. Interarea incurved gently, catacline to steeply apsacline, unstriated but bearing the trace of growth lamellae paralleling the hinge-line. Hinge-line straight and the place of maximum width. Delthyrium narrow, occupied by a complex series of plates. In small specimens these plates appear to be a pair of narrow discrete deltidial plates. With increase in shell size the plates join medially in the apical half of the delthyrium. With further increase in size another plate fills the entire base of the delthyrium except for a small foramen. In large specimens a deposit of secondary material may be laid down over the entire structure, obscuring the foramen and giving the impression of a pseudo- deltidium. Fine ornamentation consists of fine radial fila which in well-preserved speci- mens are seen to be crossed by concentric growth lamellae. The junction of the con- centric and radial ornamentation may be nodose. Anterior commissure uniplicate. Median sulcus prominent, gently rounded to subrectangular in cross-section. 702 PALAEONTOLOGY, VOLUME 5 Brachial exterior. Valve gently convex, posteriorly overhangs the pedicle valve. Interarea orthocline to apsacline. Discrete chilidial plates present on small specimens, but on large specimens may be medially conjunct. Fold gently rounded to subrectangular in cross-section. Fine ornamentation similar to that of pedicle valve. Shell impunctate. Pedicle interior. Dental lamellae long, surmounted by stubby hinge teeth. Muscle field almost free of secondary deposits, as are the umbonal cavities. A low myophragm dis- cernible in some specimens. Sulcus impressed upon the interior; peripheral regions smooth. Brachial interior. Crural plates long, support discrete chilidial plates. Area of diductor attachment unstriated. Muscle field not noticeably impressed, although a low myo- phragm is discernible in some specimens. Periphery smooth. The dental sockets narrow posteriorly and flare rapidly antero-laterally. The crura make an obtuse angle with the primary lamellae. The short jugal processes descend toward the pedicle valve near the intersection of the crura and primary lamellae. Species: Spirifer approximans Barrande 1879, pi. 4, fig. 5. Cyrtia cliftonensis Foerste 1903, J. Geo/. 11, p. 709; 1 909c/, p. 91, pi. 2, fig. 32. Anomites exporrectus Wahlenberg 1821, Nova Acta Reg. Soc. Sci. Uppsaliensis, 8, p. 64, no. 3. EXPLANATION OF PLATE 102 Figs. 1, 2. Cyrtia sp. Bilobites zone; Locality 4 24, Duck Harbor, Edmunds Township, Washington County, Maine. U.S.N.M. No. 126083. 1, Impression of interior of pedicle valve (x 3). Note the relatively long dental lamellae. 2, Impression of interior (posterior view, X 4). Note the relatively long dental lamellae and the impression of the inner face of the deltidial plate. Fig. 3. Cyrtia sp. Cedarville dolomite; Mills quarry, south-west of Springfield, Ohio. U.S.N.M. No. 87495. Impression of interior (posterior view, X 2). Note the relatively long crural plates and the unstriated area of diductor attachment. Fig. 4. Cyrtia exporrecta (Wahlenberg, 1821). Upper Visby marl; Shore at Gnisvards fisklage, Tofta parish, Klintehamn map sheet, Gotland (Boucot locality No. 56G47). U.S.N.M. No. 137734. Preparation of spire (x2). Note the short jugal process and the obtuse angle included between the crura and the primary lamella. Fig. 5. Cyrtia trapezoidalis Hisinger, 1828. Wenlock limestone; Dudley, England. U.S.N.M. No. 99909. Posterior view ( X 2). Note the narrow chilidium bordering the upper margin of the deltidial plate. Figs. 6-11. Plicocyrtia petasus (Barrande, 1848). Liten beds; Lodenice, Czechoslovakia. 6, Brachial valve (x 1). Note the lateral plications. M.C.Z. No. 9428a. 7, Side view (X 1). Note the lateral plication adjacent to the sulcus and the relatively elongate, slightly curved interarea of the pedicle valve. M.C.Z. No. 9428a. 8, Pedicle valve (x 1). Note the lateral plications bordering the sulcus. M.C.Z. No. 9428a. 9, Exterior ( X 3). Note the radially striate fine ornamentation remaining on the unexfoliated portion of the shell. M.C.Z. No. 9428c. 10, Impression of interior of brachial valve (x2). Note the elongate crural plates and the unstriated area of diductor attachment. M.C.Z. No. 9428b. 1 1 , Impression of interior of pedicle valve ( x 2). Note the relatively long dental lamellae and the myophragm medially dividing the muscle field. M.C.Z. No. 9428b. Figs. 12-17. Cyrtia exporrecta (Wahlenberg, 1821). Probably from the Upper Visby marl; Visby, Gotland. U.S.N.M. No. 53505. 12, Exterior (posterior view, x2). Note the discrete chilidial plates. 13, Exterior (posterior view, x2). Note the elongate deltidium. 14, Brachial view (x 3). Note the low, rounded fold, smooth flanks, and fine radial striae. 15, Side view (x3). Note the elongate, slightly curved interarea. 16, Anterior view (x3). Note the uniplicate anterior com- missure. 17, Pedicle view ( X 3). Note the broad sulcus and the smooth flanks. Palaeontology, Vo I. 5 PLATE 102 BOUCOT, Eospiriferidae A. J. BOUCOT: THE EOSPIRIFERIDAE 703 Cyrtia exporrecta ludlowensis Boucek 1940, p. 13, pi. ii, fig. 2. Cyrtia exporrecta maior Boucek 1940, p. 14, pi. ii, fig. 3. Cyrtia exporrecta postera Boucek 1940, p. 15, pi. i, fig. 6. Cyrtia exporrecta spiriferoides Boucek 1940, p. 15, pi. ii, fig. 4. Cyrtia externa Bolton 1957, p. 71, pi. 12, figs. 3-6. Cyrtia humilis Boucek 1940, p. 10, pi. 1, fig. 1 b. Cyrtia meta Hall 1867, 20th Rpt. New York State Cab. Nat. Hist., p. 372, pi. 13, figs. 12-13. Cyrtia myrtia Billings 1862, Paleozoic Fossils, 1, p. 165, fig. 149. Cyrtia radians Hall and Clarke 1893, Paleontology of New York, 8, pt. 2, pp. 42, 362, pi. 13, figs. 12-13. Cyrtia tasmaniensis Gill 1948, pp. 60-61, pi. 8, figs. 23-26. Cyrtia trapezoidalis Hisinger 1828, Pridrag till Sveriges geognosie, Anteckningar i physik och geognosie, 4, p. 220, pi. 6, fig. 1 a, b, c. Cyrtia trapezoidalis var. arrectus Hall and Whitfield 1872, p. 183. Distribution. In eastern North America widely distributed in strata of Upper Llan- doverian to Ludlovian age: Anticosti Island: C. myrtia, Chicotte fm.. Wen. (Twenhofel 1928, p. 219). Gaspe: C. sp. nov. aff. C. exporrecta, St. Leon fm., early Lud. (Alcock 1935, p. 50). C. cf. exporrecta, near Matapedia, Sil. (noted by writer in a collection made by Dr. Jacques Beland, Quebec Dept, of Mines). New Brunswick: C. cf. exporrecta, Mascarene series at Back Bay near St. George, U. Lland. (C6) to Wen. Maine: Cyrtia, Shin Pond quadrangle (loc. no. BB4 of R. B. Neuman), U. Lland. (C6) to Wen. (identi- fied by writer), and Eastport region (PI. 102, figs. 1-2). New York: C. myrtia and C. meta, Irondequoit Is. and Williamson sh., U. Lland. (C5 to C6) (Gillette 1947, p. 20). Kentucky: C. arrecta, strata of Louisville age (Wen.) (Hall and Clarke 1893, p. 28, figs. 2-3). Ohio: Cyrtia sp., Cedarville dolomite. Wen. (pi. 6, fig. 3). Arkansas: C. exporrecta, St. Clair Is., U. Lland. (C3 or younger) to Lud. (Thomas 1926, pp. 394-5). Wisconsin: C. radians, Racine dolomite. Wen. (Hall and Clarke 1893, p. 39, fig. 33). Indiana: C. myrtia, Liston Creek reef, Lud. (Cumings 1930, p. 209). C. trapezoidalis, Osgood fm., U. Lland. (C5 to C6) (Tillman 1961). Ontario: C. meta, Lockport dolomite, Wen. (Williams 1919, p. 67). C. extensa, Wiarton member of Amabel fm.. Wen. and Lud. (Bolton 1957, p. 71 ; pi. 12, figs. 3-6; table 1 1). British Columbia: Cyrtia sp., basal 150 ft. of Sandpile group near junction of Dali and Turnagain rivers (Geol. Surv. of Canada specimens no. 15795, 15796 from coll. No. 35174), U. Lland. (C3-C5). In Europe widely distributed in strata of Upper Llandoverian to Emsian and possibly Eifelian age, but rare elsewhere : Norway: C. exporrecta, Oslo region, U. Lland. (7c) and Wen. (8a) (Kiaer 1908, p. 589). Gotland: C. exporrecta, U. and L. Visby marl. U. Lland.; Tofta Is. and Slite group, Wen. (Hede 1921, p. 94). C. trapezoidalis, Mulde marl and Klinteberg Is., Wen. and L. Lud. (ibid.). Podolia: C. exporrecta, Kitaygorod fm. to Malinovetski fm., U. Lland. to Lud. (Nikiforova 1954, pp. 148-50). Poland: Cyrtia, Holy Cross Mts., Lud. (Tomszykowa 1959, p. 67). Urals: C. trapezoidalis, Striatus beds, Lud. (Khodalevitch 1937, pp. 69-70). Novaya Zemlya: C. trapezoidalis, Lud. (Yermolaev 1937, p. 105). Great Britain: C. trapezoidalis and C. exporrecta, U. Lland. to Lud. (observed by writer). Czechoslovakia: C. trapezoidalis, Collines entre Luzetz et Lodenitz (e2), Tachlowitz (e2), and Dlauha Hora (e2). Wen. or Lud. (Barrande 1879, pi. 8, figs. 10-15). C. approximans, Ems. or Eif. (Havli- cek 1959, pp. 73-75). C. exporrecta exporrecta, e2; C. exporrecta postera, e3; C. humilis, el; 704 PALAEONTOLOGY, VOLUME 5 C. exporrecta ludlowensis el ; C. exporrecta maior, e2; C. exporrecta exporrecta spiriferoides, e2 (Boucek 1940, plate explanation). Tasmania: C. tasmaniensis, Eldon group, Sil., as evidenced by the presence of Encrinurus (Gill 1948, pp. 60-61). The Protoleptostrophia cited by Gill 1948, pp. 64-65 from the fauna may well belong to Leptostrophia, but no information on the brachial interior is available for positive identification. Turkey: Cyrtia, Chamosite horizon near Cumakoy (NW. of Aquiran) in the Istanbul region, U. Lland. T’ien-Shan: Cyrtia sp. from locality 13 of Arpishmebulag Series, Sil. (identified from photographs provided through the courtesy of Prof. G. Regnell, Lund). Genus plicocyrtia gen. nov. Plate 102, figs. 6-11; plate 104, figs. 1-3 Type species. Cyrtia petasus Barrande 1848, Haul. Naturw. Abb. 2, p. 183, pi. 17, fig. 1; 1879, pi. 7, figs. 7-9. EXPLANATION OF PLATE 103 Figs. 1-6. Nikiforovaena ferganensis (Nikiforova, 1937). Isfara beds; outcrop 1885, northern slope of the Alai Range, Fergana. Cat. No. 1841/5037 (Holotype). 1, Anterior view (x 1). Note the grooved fold and corresponding rib in the sulcus. 2, Pedicle view (x 1). 3, Branchial view (x 1). 4, Posterior view(xl). 5, Side view (x 1). 6, Fine ornamentation (x 5). Note the eospiriferid-type striae. Figs. 7-9. Janius sp. Strata of Ludlovian age; Junction of road and Gambol Brook (loose blocks almost in situ), Field No. CE-16, Stratum No. 30801, Tetagouche Lakes area, New Brunswick, Canada. L. M. Cumming, collector, 1957. 7, Impression of interior of pedicle valve ( X 2). Note the plication in the sulcus. G.S.C. No. 15152. 8, Impression of portion of exterior (x2). Note the eospiriferid-type striations. G.S.C. No. 15153. 9, Impression of interior of pedicle valve (x2). Note the anteriorly bifurcating lateral plications and the plication in the sulcus. G.S.C. No. 15154. Figs. 10, 11. Janius sp. Strata of Ludlovian age; Small island near southern end of Whitehorse Lake, Shin Pond quadrangle, Maine. U.S.N.M. No. 137737. 10, Impression of exterior (x 3). Note the eospiriferid-type striations and the anteriorly branching lateral plications. 1 1 , Impression of pedicle valve interior ( X 3). Figs. 12-17. Havlicekia sp. Lower portion of Lochkov limestone. Svaty Jan pod Skalou, small valley under the hill ‘ Mramor ’, south-west of the village. Right side of the Kacak stream, Czechoslovakia. Boucot locality No. B-60-32. 12, Posterior view (x 1). 13, Pedicle view (x 1). 14, Brachial view (xl). 15, Anterior view (x 1). 16, Side view (x 1). 17, Posterior view (x 2). Note the long crural plates and the unstriated area for diductor attachment. U.S.N.M. No. 137738. EXPLANATION OF PLATE 104 Figs. 1-3. Plicocyrtia petasus (Barrande, 1848). Liten beds; Lodenice, Czechoslovakia. M.C.Z. No. 9248a. 1, Posterior view (x 1). Note the deltidial cover. 2, Anterior view 3, (x 1). Anterior view (x 1). Note the short dental lamella. Figs. 4-8. Cyrtia exporrecta (Wahlenberg, 1821). Upper Visby marl; Gotland. Pal. Inst. Uppsala, Wahlenbergs samling Nr. G. 199. These figures are of the lectotype, which is here designated from the three cotypes. 4, Brachial view ( X 3). 5, Pedicle view ( X 3). 6, Posterior view ( X 3). 7, Anterior view ( X 3). 8, Side view ( X 3). Figs. 9-14. Janius insignis (Hedstrom, 1923). Eke Group; Lau backar, 1-3 km. north-east of Church of Lau, parish of Lau, Gotland. Collected and identified by Dr. J. E. Hede. 9, Side view (x3). U.S.N.M. No. 137735. 10, Pedicle view (x3). Note the plication in the sulcus. U.S.N.M. No. 137735. 11, Brachial view (x 3). Note the grooved fold. U.S.N.M. No. 137735. 12, Anterior view (x3). U.S.N.M. No. 137735. 13, Posterior view (x3). Note the ribbon-like deltidial plates. U.S.N.M. No. 137735. 14, Posterior view of internal impression ( x 3). Note the long crural plates. U.S.N.M. No. 137736. Palaeontology, Vol. 5 PLATE 103 BOUCOT, Eospiriferidae Palaeontology, Vol. 5 PLATE 104 BOUCOT, Eospiriferidae A. J. BOUCOT: THE EOSPIRIFERID AE 705 Diagnosis. Cyrtiinids bearing lateral plications on either side of the fold and sulcus. Comparison. Plicocyrtia differs from Cyrtia only in having lateral plications on either side of the fold and sulcus. Pedicle exterior. Valve pyramidal, laterally elongate tending to become alate. Interarea unstriated, gently incurved, catacline to steeply apsacline. Hinge-line straight, equal to maximum width. Delthyrium narrow, elongate, filled by a convex deltidial plate. The detailed structure and mode of origin of the deltidial plate is not known. Fine orna- mentation consists of fine radial fila. Anterior commissure uniplicate and crenulate. Sulcus prominent, rounded in cross-section, bordered laterally by one to three lateral plications having low, rounded cross-sections and separated by broad, U-shaped inter- spaces. Flanks smooth. Brachial exterior. Valve gently convex, laterally elongate tending toward alation; posteriorly it overhangs the pedicle valve. Shell impunctate. Interarea orthocline to apsacline. The presence or absence of chilidial plates was not determined. Fold rounded in cross-section, bordered laterally by one to three plications lateral to which the flanks are smooth. Fine ornamentation same as that of pedicle valve. Pedicle interior. Hinge teeth stubby, supported basally by the long, thin dental lamellae. Muscle field and umbonal cavities almost free of secondary deposits. A well-developed myophragm medially divides the muscle field and extends anteriorly to about the mid- length. The external ornamentation is impressed upon the interior. Brachial interior. The cardinalia consist of slender crural plates which laterally border the unstriated area of diductor attachment and basally support the discrete hinge-plates. A low myophragm bisects the feebly impressed muscle field and extends anteriorly past the midlength. Species: Cyrtia petasus Barrande 1848, Haicl. Naturw. Abh. 2, p. 183, pi. 17, fig. 1. Distribution. Known from the Upper Liten beds (uppermost Wenlockian) of Czecho- slovakia, and possibly from strata of Ludlow age in Turkestan if C.? aff. petasus (Nikiforova 1937, p. 51) belongs to the genus. EVOLUTION OF THE EOSPIRIFERID AE The oldest known genera of the family Eospiriferidae (text-fig. 4), Eospirifer and Cyrtia, appear in strata of early Upper Llandovery age on both sides of the North Atlantic. The similar cardinalia, spires, interiors of pedicle valves, and fine ornamenta- tion of both genera clearly suggest that they have a common ancestor somewhere in pre-Upper Llandoverian time. Both genera belong to the brachiopod fauna which first appears in the North Atlantic region during Upper Llandoverian time from an unknown area. Among known Ordovician or pre-Upper Llandoverian brachiopods there are no closely related genera and, in fact, no genera that could reasonably be included in the same family. The Cyrtiinae, as exemplified by Cyrtia, appear to have been a relatively stable stock which, for unknown reasons, did not give rise to such diverse plicated forms 706 PALAEONTOLOGY, VOLUME 5 as those in the Eospiriferinae. The genus Eospirifer, for example, by the development of different types of plications on flanks and sulcus proliferated a number of genera. The gradual transition between specimens with smooth flanks {Eospirifer) and those with undulating plications separated by U-shaped interspaces of the Macropleura type, or those with V-shaped interspaces of the Striispirifer type, strongly suggests that EIFELIAN / \ / \ / \ t \ / \ EMSIAN 1 \ SIEGENIAN GEDINNIAN Macro pleura SKALIAN Nikiforovaena LUDLOVIAN Phcocyrtia Jar J ius \ 1 \ V Eos / vrifer Havlic ekia WENLOCKIAN 7 / / J N s' s' Slri/Sf oirifer ^ \ > UPPER LLANDOVERIAN Cyrl . J N ia L . \ / Vs PRE-UPPER LLANDOVERIAN Cyrtmae Eospiriferinae text-fig. 4. Relations of the Eospiriferidae. Eospirifer was ancestral to both of the latter genera. It is probable that the long-lived stock of smooth-flanked eospiriferids repeatedly gave rise to forms with plicated flanks, but this cannot be demonstrated on the basis of available collections and information. Some relevant information comes from the genus Havlicekia. Havlicek (1959, pp. 52- 53) has concluded, on morphological grounds, that the Ludlovian species E. praesecans from the Kopanina beds is ancestral to the Lower Devonian form H. secans, as large specimens of both have the peculiarly large, steep-sided fold with U-shaped cross- section. It is more probable that E. praesecans is ancestral to E. togatus togatus, which, as described by Havlicek (ibid., pp. 42-43), is very similar to E. praesecans , and that El. turjensis, which occurs in the Pridoli beds (overlying the Kopanina beds) and also in the Urals in strata reported to be of Wenlockian age (Khodalevitch 1939, pp. 65-66), is ancestral to H. secans. A. J. BOUCOT: THE EOSPIRIFERTDAE 707 The Kopanina beds also contain Striispirifer viator, which has a steep-sided fold similar to that of Havlicekia and E. praesecans. This suggests that at least one species of Striispirifer was derived from a smooth eospiriferid similar to E. praesecans in pre- Kopanina time (presumably during the late Llandovery), and that Havlicekia was derived from a similar source at about the same time. From a consideration of fold cross- sections, it seems likely that species of Striispirifer similar to S. niagarensis were derived from an Eospirifer similar to E. radiatus, which suggests that Striispirifer is polyphyletic. Macropleura is transitional to the later-appearing genus Janius, the early growth stages of which have Macropleura- type ornamentation. On morphological grounds, the U-shaped interspaces between the rounded plications of Nikiforovaena ally it closely with Macropleura, and it is concluded that the former was derived from the latter by the development of a plicated fold and sulcus. The coarse ornamentation of Plicocyrtia suggests its origin from the implicated genus Cyrtia. From a phylogenetic point of view, the Eospiriferidae show a repeated tendency to develop forms with lateral plications in the adult (large specimen), whereas the early growth stages are usually reminiscent of an ancestral type (e.g. smooth, unplicated umbonal beak region in such genera as Mcicropleura, Striispirifer, and Plicocyrtia ). Havlicekia suggests that the genetic processes responsible for the development of lateral plications in adults could also operate in the reverse manner, to produce lateral plications in the umbonal region in the young and smooth flanks in the adult. ‘ Eospirifer ’ iorensis Nikiforova 1937, from strata of Ludlow age in Turkestan, is un- doubtedly an eospiriferid, as evidenced by its fine ornamentation. The presence of a deep groove in its fold, associated with a corresponding rib in the sulcus, separates it generically from all other members of the Eospiriferidae, but the writer does not propose a new genus to receive this unique species because its internal morphology is not clear. Flavlicek (1959, p. 231) noted that both ‘ Eospirifer ’ olgae Borisyak 1955 and ‘ Eospirifer ’ kassini Borisyak 1955 may belong to a group in which the brachial valve bears a sulcus containing a median plication. Inspection of Borisyak’s figured specimens shows that they are too fragmentary for certainty on this point, although their fine ornamentation indicates they are undoubtedly eospiriferid. STRATIGRAPHIC VALUE OF THE EOSPIRIFERIDAE Members of the Cyrtiinae are known in beds of Upper Llandoverian to possible Eifelian age, and members of the Eospiriferinae from beds of Upper Llandoverian to Eifelian age. Representatives of both groups occurring in pre-Upper Llandoverian beds will probably eventually be found. Eospirifer itself ranges from the Upper Llandoverian to the Eifelian. In the North Atlantic region. Macropleura appears in uppermost Llandoverian time; it continues through Gedinnian time and possibly into the lowest Siegenian interval, although elsewhere it persisted into Eifelian time. Striispirifer appears in uppermost Llandoverian time and continues through to Eifelian time. Janius appears in uppermost Wenlockian time and continues into the Eifelian. The species of Janius without plicae on the fold or sulcus appear earlier (in late Wenlockian time) than those forms with such plicae (Ludlow), making it possible to distinguish between beds of 708 PALAEONTOLOGY, VOLUME 5 latest Wenlockian to Ludlovian age on this basis. Nikiforovaena is known in strata of Ludlovian age. Havlicekia is known from strata of Wenlockian to Eifelian age. In North America, eospiriferids are not known after the Gedinnian (New Scotland formation and its equivalents). In the Old World, eospiriferids normally occur as high as the Emsian, except in the Rhenish facies of northern Europe where they are unknown in either the Siegenian or Emsian, and in Central Asia and Czechoslovakia, where they also occur in the Eifelian. The available distribution data suggests that the family be- came progressively restricted geographically after the Gedinnian until, by the end of Eifelian time, they became extinct. REFERENCES alcock, F. j. 1935. 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New York State Mus. 1, 1-95. and dodge, w. w. 1892. On the occurrence of Upper Silurian strata near Penobscot Bay, Me. Amer. J. Sci. 3, 43, 412-18. billings, e. 1869. Description of some new species of fossils with remarks on others already known from the Silurian and Devonian rocks of Maine. Proc. Portland {Maine) Soc. Nat. Hist. 1, 104-26. bolton, t. E. 1957. Silurian stratigraphy and palaeontology of the Niagara escarpment in Ontario. Mem. Canada Geol. Surv. 289, 1-145, pi. 1-13. Boris yak, M. A. 1955«. Material on the stratigraphy and fauna of the Ordovician and Silurian sedi- ments of Central Kazakhstan, No. 1, Silurian (Wenlockian) brachiopods from Karaganda oblast. All-Union Sci. Inv. Geol. Inst. ( VSEGEI ), n.s., Paleont. and Stratigr. 3, 1-92. 19556. Material on the stratigraphy and fauna of the Ordovician and Silurian sediments of Central Kazakhstan, No. 2, Stratigraphy and brachiopods of the Silurian of the region of the Chinghiz Mountains. Ibid. 5, 1-108. 1960. Conference on the unification of the stratigraphic scheme of the pre-Paleozoic and Paleozoic of Eastern Kazakhstan. T. 1, pre-K, K, O, S. Acad. Sci. Kazakhstan, Alma-Ata, 1-298. boucek, b. 1940. Uber die Varibilitat der Brachiopoden Dayia navicula (Sow.) und Cyrtia exporrecta (Wahl.). Mitt. Tschech. Akad. Wiss. 50, 1-17. boucot, A. j. 1960. Lower Gedinnian brachiopods of Belgium. Mem. Inst. Geol. Louvain, 21, 283-324. 1961. The Lower Paleozoic rocks of west-central Maine. Bull. U.S. Geol. Surv. 1111. et al. 1958. Metamorphosed Middle Paleozoic fossils from central Massachusetts, eastern Vermont, and western New Hampshire. Bull. Geol. Soc. Amer. 69, 855-870. and Thompson, j. b., jr. 1958. Late Lower Silurian fossils from sillimanite zone near Claremont, N.H. Science, 128, 3320, 362-3. butts, Charles. 1940. Geology of the Appalachian Valley in Virginia. Bull. Virginia Geol. Surv. 52, 1-568. cairnes, d. d. 1914. The Yukon-Alaska International Boundary, between Porcupine and Yukon Rivers. Mem. Geol. Surv. Canada, 67. A. J. BOUCOT: THE EOSPIRIFERIDAE 709 chapman, f. in jutson 1908. The Silurian rocks of the Whittlesea District. Proc. Roy. Soc. Victoria, 21 (n.s.), 1, 211-25. chernychev, b. b. 1937. The Silurian brachiopods of Mongolia and Tuva. Trudy Mongolian Comm. 29, Izdatelstvo Akad. Sci. USSR, 1-94. clarke, J. m. 1909. Early Devonic history of New York and eastern North America. Mem. New York State Mas. 9, pt. 2, 1-250. cumings, e. r. 1930. Silurian studies. Proc. Indiana Acad. Sci. 39, 183-211. DAVIDSON, t. 1871. The Silurian brachiopods: A monograph of the British fossil Brachiopoda, pt. 7, 4, 249-397. dunbar, c. o. 1919. Stratigraphy and correlation of the Devonian of western Tennessee. Bull. Tennessee State Geol. Surv. 21, 1-127. foerste, a. f. 1909a. Fossils from the Silurian formation of Tennessee, Indiana, and Kentucky. Bull. Denison Univ. Sci. Lab. 14, 61-116. 19096. Silurian fossils from the Kokomo, West Union, and Alger horizons of Indiana, Ohio, and Kentucky. J. Cincinnati Soc. Nat. Hist. 21, 1-141. 1935. Correlation of Silurian formations in south-western Ohio, south-eastern Indiana, Kentucky and western Tennessee. Bull. Denison Univ. Sci. Lab. 30, 119-205. gigout, m. 1951. Etudes geologiques sur la Meseta Marocaine Occidentale. 77 a v. Inst. Sci. Cherifien, Rabat, 3, t. 1, 1-507. gill, e. g. 1948. Eldon group fossils. Rec. Queen Victoria Mas., Launceston, Tasmania, 2, 57-74. 1949. Devonian fossils from Sandy’s Creek, Gippsland, Victoria. Mem. Nat. Mus. Victoria, 16, 91-115. 1950. Palaeontology and palaeoecology of the Eldon group. Papers and Proc. Roy. Soc. Tasmania, 231-58. Gillette, tracy. 1947. The Clinton of western and central New York. Bull. New York State Mus. 341, 1-197. gortani, m. 1915. Fossili Eodevonici della base del Capolago (Seekopfsockel). Palaeontographica Italica, 21, 117-88. grabau, a. 1926. Silurian faunas of eastern Yunnan. Pal. Sinica, China Geol. Surv. 3, Ser. B, fasc. 2, 1-86. hall, james and clarke, j. m. 1 893. An introduction to the study of the genera of Palaeozoic Brachio- poda, Pt. II. New York Geol. Surv. 1-394. and Whitfield, r. p. 1872. 24th Ann. Rpt. New York State Mus. Nat. Hist, for 1871. 1875. 25th Ann. Rpt. New York State Mus. Nat. Hist, for 1876. hamada, t. 1961. The middle Palaeozoic group of Japan and its bearing on her geological history. Jour. Faculty Science Univ. Tokyo, sec. II, xm, pt. 1, 1-79. havlicek, vladimir. 1957a. Further new genera of the family Spiriferidae in the Silurian and Devonian of Bohemia. Vestnik UUG, roc. 32, 436-40. 19576. On new genera of Spiriferidae of Bohemia (Brachiopoda). Vestnik UUG, roc. 32, 245-8. 1959. The Spiriferidae of the Silurian and Devonian of Bohemia. Rozpravy UUG, svazek 25, Prague. hede, j. e. 1921. Gottlands silurstratigrafi. Sver. geol. Undersok., ser. C, 305, 1-100. 1927a. Berggrunden (Silursystemet) in munthe, henr., hede, j. e., and von post, lennart. Beskrivning till kartbladet Hemse. Ibid., ser. Aa, 164, 1-155. 19276. Berggrunden (Silursystemet) in munthe, henr., hede, j. e., and lundqvist, g. Beskrivning till kartbladet Klintehamm. Ibid., ser. Aa, 160, 1-109. 1928. Berggrunden (Silursystemet) in munthe, henr., hede, j. e., and lundqvist, g. Beskrivning till kartbladet Slite. Ibid., ser. Aa, 169, 1-130. 1933. Berggrunden (Silursystemet) in munthe, henr., hede, j. e., and lundqvist, g. Beskrivning till kartbladet Kappelshamn. Ibid., ser. Aa, 171, 1-129. — — 1936. Berggrunden in munthe, henr., hede, j. e., and lundqvist, g. Beskrivning till kartbladet Faro. Ibid., ser. Aa, 180, 1-82. 1940. Berggrunden in lundqvist, g., hede, j. e., sundius, n. Beskrivning till kartbladen Visby och Lummelunda. Ibid., ser. Aa, 183, 1-167. hedstrom, h. 1923. Contributions to the fossil fauna of Gotland. Ibid., Undersok. ser. C, 316, 1-24, 710 PALAEONTOLOGY, VOLUME 5 kayser, emanuel. 1878. Die Fauna der altesten Devon-Ablagerungen des Harzes. Abh.Geol. Special- karte Preuss. Geol. Landesanst., Bd. 2, h. 4, 1-295, 36 pi. (in separate Atlas). khalfin, l. l. 1948. Fauna and stratigraphy of the Devonian beds of the High Altai. Trans. Tomsk Polytechnic Inst. 65, 1, 1-464. khodalevitch, A. N. 1937. The Lower Devonian of the Ivdel Region (eastern slope of the Urals). Mat. Central Geol. and Prospecting Inst., Paleont. and Stratigr., Mag. 3, 64-70. ■ 1939. Upper Silurian Brachiopoda of the eastern slope of the Urals. Trans. Ural Geol. Serv . 1-135. 1951. Lower Devonian and Eifelian brachiopods of the Ivdelsk and Serovsk regions of Sverdlovsk Oblast. Works of Sverdlovsk Mining Inst. 18, 1-169. kiaer, j. 1908. Das Obersilur im Kristianiagebiete. Vidensk.-Selsk. Skr., I. Math. Naturv. Kl. 106, Bd. 2, 1-595. kindle, e. m. 1908. Geologic reconnaissance of the Porcupine Valley, Alaska. Bull. Geol. Soc. America, 19, 315-38. kirk, e., and amsden, t. w. 1952. Upper Silurian Brachiopoda from south-eastern Alaska. U.S.Geol. Surv. Prof. Paper, 233C, 53-66. le maitre, d. 1934. Etudes sur la faune des Calcaires Devoniens du Bassin d’Ancenis. Mem. Soc. Geol. Nord. 12, 1-267. 1952. La faune du Devonien inferieur et moyen de la Saoura et des abords de l’Erg el Djernel (Sud-Oranais). Mat. pour Carte Geol. de VAlgerie, 1st ser., Paleont. 12, 1-170. Lesley, j. p. 1890. A dictionary of the fossils of Pennsylvania. Pennsylvania Geol. Surv., Rpt. pt. 4, 3, 915-1283. luha, A. 1930. Uber Ergebnisse stratigraphischer Untersuchungen im Gebiete der Saaremaa-(Osel)- Schichten in Eesti (Unterosel und Eurypterusschichten). Acta et Comm. Univ. Tartu, A18; Publ. Geol. Inst. Univ. Tartu, 22, 1-18. mclearn, F. H. 1924. Palaeontology of the Silurian rocks of Arisaig, Nova Scotia. Canada Geol. Surv. Mem. 137, 1-180. maehl, r. H. 1961. The Older Palaeozoic of Pictou County, Nova Scotia. Nova Scotia Dept, of Mines, Mem. 4, 1-112. mitchell, j. 1921. Some new brachiopods from the Middle Palaeozoic Rocks of New South Wales. Proc. Linnean Soc. New South Wales, 45, 543-51. nalivkin, d. 1930. Brachiopods from the Upper and Middle Devonian of the Turkestan. Mem. Coni. Geol., n.s., 180, 1-221. 1936. The Middle Paleozoic faunas of the head parts of the Kolyma and Kandy ga rivers in The Paleozoic faunas of the Kolyma. Contr. to Knowledge of Okhotsk-Kolyma Land, ser. 1, fasc. 4, State Trust Dalstroy, 1-28. 1960. New species of Devonian Atrypidae and Spiriferidae of the Arctic. New species of fossil plants and invertebrates of the USSR, pt. 1, 380-96, All-Union Sci. Res. Geol. Inst. ( VSEGEI ), Moscow. nettleroth, H. 1889. Kentucky fossil shells: a monograph of the fossil shells of the Silurian and Devonian rocks of Kentucky. Kentucky Geol. Surv. 1-245. Nikiforova, o. i. 1937«. Upper Silurian fauna of the western Balkhash Land. Contr. to Knowledge of western Balkhash Land, Central Geol. and Prospecting Inst., Moscow, 11-36. 19376. Brachiopods of the Upper Silurian of the central Asian part of the USSR, Pt. 1. Mon. of Paleontology of USSR, 35, 1-94. 1954. Stratigraphy and brachiopods of the Silurian series of Podolia. Trav. United Res. Geol. Inst. 1-218. Northrop, s. a. 1939. Paleontology and stratigraphy of the Silurian rocks of the Port Daniel-Black Cape Region, Gaspe. Geol. Soc. Amer. Spec. Paper, 21, 1-302. paeckelmann, w. 1925. Beitrage zur Kenntnis des Devons am Bosporus, insbesondere im Bithynien. Abh. Preuss. Geol. Landesanst., n.f., 98, 1-152. poulsen, c. 1934. The Silurian faunas of North Greenland, I. Medd. om Gron. 72, 1, 1-46. 1943. The Silurian faunas of North Greenland, II. Ibid. 3, 1-59. prouty, w. F., and swartz, c. k. 1923. Sections of the Rose Hill and McKenzie formations. Mary- land Geol. Surv., Sil. 53-104. A. J. BOUCOT: THE EOSPIRIFERIDAE 711 reed, F. r. c. 1906. The Lower Palaeozoic fossils of the northern Shan States, Burma. India Geol. Surv. Mem., Pal. Indica, n.s., 2, Mem. 3, 1-154. regnell, G., and hede, j. e. 1960. The lower Paleozoic of Scania, the Silurian of Gotland. Internal. Geol. Congr., 21st Sess. , Norden, 1-87. roemer, f. 1860. Die silurische fauna des westlichen Tennessee. Breslau, 1-100. rzonsnitskaya, M. a. 1952. Spiriferidae of the Devonian series of the margins of the Kuznetsk Basin. Trav. United Acad, and Res. Geol. Inst. 1-232. st. Joseph, j. k. s. 1935. A description of Eospirifer radiatus (J. de C. Sowerby). Geol. Mag. 72, 316-27. schmidt, f. 1881. Revision der ostbaltischen Silurischen Trilobiten. Mem. Acad. Imp. Sci. St.- Petersburg, 7th ser., 30, abt. 1, 1-237. schuchert, Charles. 1913. Systematic paleontology of the Lower Devonian deposits of Maryland, Brachiopoda. Maryland Geol. Surv., Lower Dev., 290-449. ■ — — and cooper, g. a. 1932. Genera of the suborders Orthoidea and Pentameroidea. Mem. Peabody Mas. Nat. Hist., New Haven, 4, 1, 1-270. shirley, J. 1938. The fauna of the Baton River beds (Devonian), New Zealand. Quart. J. Geol. Soc. London, 94, 459-506. shrock, r. r., and twenhofel, w. h. 1939. Silurian fossils from northern Newfoundland. J. Paleont. 13, 3, 241-66. termier, h. 1936. Etudes geologiques sur le Maroc Central et le Moyen Atlas Septentrional. Serv.de Mines et Carte Geol. 3, Notes et Mem., no. 33, Paleont. 1-1566. thomas, n. l. 1926. Brachiopods from the St. Clair limestone, Arkansas. Denison Univ. J. Sci. Lab. Bull. 21, 385-401. tillman, c. G. 1961. Stratigraphy and brachiopod fauna of the Osgood formation, Laurel limestone, and Waldron shale of south-eastern Indiana. Ph.D. thesis, Harvard Univ. tomczykowa, E. 1959. Preliminary study of the Middle and Upper Ludlow stratigraphy in the Swiety Krzyz Mts. Przeglad Geologiczny, 7, 2 (71), 65-73. tschernychev, th. 1893. Materialien zur Kenntniss der devonischen Fauna des Altais. Verh. Russ.-K. Min. Gesell., ser. 2, 30, 1-40. twenhofel, w. h. 1928. Geology of Anticosti Island. Canada Geol. Surv. Mem. 154, 1-481. 1941. The Silurian of Aroostook County, northern Maine. J. Paleont. 15, 166-74. vascautanu, th. 1932. Formatiunile Siluriene din malul Romanesc al Nistrului. Ann. Inst. Geol. Romaniei, 15, 425-663. wang, Y. 1956. New species of brachiopods (II). Scientia Sinica, 5, 3, 577-601. weller, s. 1903. The Paleozoic faunas. New Jersey Geol. Surv., Paleont. 3, 1-462. williams, m. y. 1919. The Silurian geology and faunas of Ontario Peninsula and Manitoulin and adjacent islands. Canada Geol. Surv. Mem. Ill, 1-195. Yermolaev, M. m. 1937. Stratigraphy of palaeozoic deposits on Novaya Zemlya. 17th Internal. Geol. Cong., Novaya Zemlya Excursion, Pt. 1st general, 91-134. A. J. BOUCOT Division of Geological Sciences, California Institute of Technology, Pasadena, California, U.S.A. Manuscript received 13 July 1961 POLYMORPHINIDAE FROM THE UPPER CRETACEOUS OF ENGLAND by TOM BARNARD Abstract. Various Cretaceous species of Polymorphinidae have irregular fistulose end-chambers. Similar forms occur from the Jurassic to Recent. The Upper Cretaceous fistulose forms are considered to be abortive offshoots from either the chief smooth species or from the rarer ornamented forms. Their taxonomic significance and occurrence is discussed. Members of the family Polymorphinidae are closely related to the Lagenidae (or Nodosariidae), possessing similar wall-structures, chamber-shapes and apertures, and differing only in the arrangement of the chambers. In the Lagenidae the chambers are usually arranged in a uniserial order, with the main axis being either straight, curved, or even planispiral, whereas in the Polymorphinidae the chambers are arranged in a spire about a vertical axis, but placed at angles about this axis. Their morphological development and suggested evolution was dealt with by Cush- man and Ozawa (1930) in a monograph of Recent and Tertiary forms. A classification was put forward based on the arrangement of the chambers in a large number of specimens, widely distributed both in space and time. It would appear that the smooth, primitive forms, Globulina and Guttulina, have not only a long geological history, but also a wide distribution in various rocks. Some genera, particularly those occurring in Tertiary rocks and Recent oceans, are restricted in their distribution, becoming highly selective and specialized. Many of these species are greatly restricted in both vertical and horizontal range. Smooth forms appear to have long ranges, whereas ornamented genera do not range widely. This may be an illusion primarily due to the difficulty in differentiating between the smooth genera and species. It is clear that overlap occurs in many early ‘species’ of Guttulina and Eogut- tulina, and specific determination is difficult. It appears from the study by Cushman and Ozawa (1930) that although the family Polymorphinidae made its first appearance during the Trias, and the Jurassic forms representing the genus Eoguttulina were of an extremely simple plan, it was not until the Cretaceous that any generic diversity occurred. This view is oversimplified, for great diversity of form does occur in the Jurassic. Individual variation in the arrangement of the chambers is well seen in specimens from the Lias, Oxford Clay, and Kimeridge Clay of England. Many variants show a chamber arrangement identical to that in forms which do not appear as definite genera until late in the Cretaceous. However, whereas the Cretaceous species become well established, most of the Jurassic variants are short-lived and do not persist. Most of the genera belonging to this family were represented before the end of the Cretaceous. Throughout the Jurassic and Cretaceous the species generally had their chambers arranged at angles around a vertical axis, and this, together with the shape of the chambers, tended to produce globular or fusiform tests. However, in Tertiary times [Palaeontology, Vol. 5, Part 4, 1962, pp. 712-26. ] TOM BARNARD: POLYMORPHINIDAE FROM ENGLAND 713 some forms (and occasional abnormal specimens from the Cretaceous) tended to have the chambers arranged biserially. Although members of the Polymorphinidae occur sporadically throughout the Mesozoic rocks of England, they are generally rare except at scattered horizons where they may be extremely abundant. The author has not observed any species with irregular or fistulose end-chambers occurring in Jurassic rocks, although they are recorded by Terquem (1864). Apparently fistulose forms do not occur until the Cretaceous. Many such forms have been recorded from the Lower and Upper Cretaceous rocks of both Europe and America, and speci- mens are also rare throughout Tertiary to Recent times. Bullard (1953), in a paper on the ' Polymorphinidae of the Cretaceous (Cenomanian) Del Rio Shale’ from Texas, records a number of fistulose forms and suggests that ‘. . . all the various modes of growth known to the family, such as free, attached, fistulose, tubulose, and racemose are represented in the Del Rio fauna. This evidence suggests that the family had reached a mature stage in its development long before the Tertiary. . . . The extensive development of the Polymorphinidae by Del Rio time reflects a rapid expansion of the family during the Washita. . . .’ Tappan (1940, 1943) recorded eight species from the Duck Creek Formation (basal Washita), and ten from the Grayson Formation, whereas nineteen are recorded from the Cenomanian. This rapid increase in development also occurs throughout the Albian of southern England and is continued into the Cenomanian, although the big increase in number of species recorded from America is probably due to the setting up of many new species, which are, in fact, just variants of well-established forms. Little account of the variation has been taken in assigning specimens to species. Bullard suggests by her naming that fistulose forms are new species and not variants of well-established, and often long-ranged, species. Globulina fistulosa Bullard (p. 342), although rare in the Del Rio Formation, differs from its contemporary species Globulina lacrima Reuss only in having a fistulose end-chamber. Also Pyrulina cylindroides (Roemer) appears to have a similar relationship to the fistulose Pyrulina longa (Tappan). From the foraminiferal occurrence charts of the Del Rio Formation it is apparent that in most cases the forms occur together in pairs, and their ranges are contemporaneous for the whole formation, except that the smooth forms have longer ranges, as might be expected. The present author believes that fistulose forms, as well as many attached forms belonging to this family, are abortive variants of smooth, or in rare cases ornamented species, and should not be regarded as true species, for they are of sporadic occurrence and do not appear to have become firmly established. At certain horizons, however, the abnormal forms greatly increase in number, momentarily in time, and this may be due to internal or external environmental factors. In the Albian of England as with the Washita of America, a number of fistulose forms occur, but in England the lithology is constant and does not appear to reflect any change in environment. Fistulose specimens also occur in the Cenomanian in England, and here with the rapidly changing lithologies it would be easy to invoke environmental changes to produce aberrant forms. Throughout the Turonian and Senonian, fistulose forms occur rarely and sporadically until the Belemnitella mucronata zone, where a distinct shallowing of the sea took place. 714 PALAEONTOLOGY, VOLUME 5 as reflected by the more arenaceous nature of the Chalk. In some ways the residues from Chalk samples and the organic content resemble the Lower Cenomanian. The continued shallowing of the mucronata- chalk is shown by the Maestrichtian of Holland. Here an abundance of various species of polymorphinids occurs, often with fistulose forms. In order to make the evolutionary history of the Polymorphinidae more complete, specimens have been figured from certain horizons within the Dutch sequence. At other horizons besides the Upper Cretaceous, abnormal, fistulose, pustulose, or hispid forms occur belonging to a variety of different genera and species. It soon be- comes apparent from a study of the literature and samples from numerous horizons from Lower Jurassic to Recent, that at scattered levels these abnormal forms are pro- duced haphazardly. They are often few in number compared with the root form. They occur in the genera Polymorphina , Pyrulina, Pyrulinoides, Guttulina, and Globulina. Forms ornamented with costae are extremely rare, and the majority of species are smooth or abnormally hispid, pustulose, or fistulose. Terquem (1864), in his monograph on the Lias polymorphinids, figures two species, Polymorphina breoni Terquem and P. cruciata Terquem, and amongst the numerous figures given, a few forms occur showing hispid tests. The ornament covers all the test, and is not confined to the end-chambers only. Amongst forms figured by Tappan (1940) from the Grayson Formation (Albian) is the species Pyrulina longa Tappan, an elongate form with a small but well-formed fistulose end. Tappan states (p. 114) ‘aperture generally obscured by a fistulose growth which has openings at the ends of the tubes’. Apparently this species is non-hispid, non- pustulose, with well-marked sutures. Certain Tertiary species are worthy of attention. Globulina inaequalis Reuss var. spinata Cushman and Ozawa from the Upper Oligocene bears strong spines or tubes over the whole surface, hence differing from the typical species. Terquem (1878, pi. 4, figs. 9-12) shows variation in Globulina oviformis Terquem, an Upper Pliocene species. Figs. 9, 10 show normal smooth forms, whereas figs. 11, 12 show numerous outgrowths which may be confined to the last chamber or distributed over the whole test. In the Tertiary of the Vienna basin d’Orbigny (1846) records Globulina tubulosa d’Orbigny (p. 228, pi. 13, figs. 15, 16), a smooth globular form with a stellate fistulose, but smooth outgrowth. Terquem (1878, p. 39, pi. 3, figs. 20, 21), in a monograph on the Upper Pliocene Foraminifera from Rhodes Island, shows one figure of Polymorphina praelonga Terquem to have a smooth fistulose outgrowth almost stellate in development. A number of authors working on Recent forms have also recorded abnormalities. Williamson (1858, p. 72, pi. 6, fig. 150), when describing Polymorphina lactea (Walker) var. fistulosa Williamson, states ‘. . . develops numerous irregular expansion and tubular growths. Ends which frequently dichotomise are often open, but I believe this to be the result of accident, and that in their normal state they are mere cul-de-sacs.’ This is contrary to the opinion of the present author, who has observed many open tubes in this group of fossils, some broken, but many well formed, and obviously serving as supplementary apertures. Some species, for example Polymorphina longicollis Brady (1881, p. 64, pi. 73, figs. 18, 19), show later chambers only becoming hispid, coupled with the development of a long, single apertural neck, the latter often having a well-marked lip. Cushman (1923) shows TOM BARNARD: POL YMORPHINIDAE FROM ENGLAND 715 some specimens of Polymorphina extensa Cushman to have hispid ends with the apertures occurring on elongate narrow tubular necks. Systematic descriptions of the various species from the Chalk are given below together with an account of the abnormalities in certain species. Specimens in the British Museum (Natural History) have the prefix bm. SYSTEMATIC DESCRIPTIONS Genus globulina d'Orbigny 1839 Genotype. Polymorphina ( Globulina ) gibba d’Orbigny. The two genera Apiopterinci and Raphanulina were proposed by Zborzewski 1834; both the figured specimens are fistulose forms. The former, with the monotypic species Apiopterina d'Orbignyi, appears to be a fistulose specimen of a species belonging to the genus Pyrulina, and the latter, Raphanulina humboldtii, belongs to the genus Globulina. However, the two genera Apiopterina and Raphanulina predate Pyrulina and Globulina respectively as pointed out by Galloway (1933), and it is possible that if the forms were accurately described (if the type specimens are still in existence), that they would replace the genera Pyrulina and Globulina. On the grounds of common usage it is intended in the present paper to retain the genera Pyrulina and Globulina. Also, because the original descriptions take no account of the arrangement of the chambers it would be difficult to place these forms correctly. The present author is of the opinion that the fistulose forms are abortive offshoots of more normal polymorphine species, and it is inadvisable to establish genera on this evidence. Globulina lacrima Reuss Text-figs, la, b, k, l 1845 Polymorphina ( Globulina ) lacrima Reuss, p. 40, pi. 12, fig. 6. 1891 Polymorphina proteus Beissel (pars), p. 59, pi. 11, figs. 1-6; pi. 13, fig. 83; pi. 12, figs. 9- 16 ( non 13). 1896 Polymorphina gibba d’Orbigny; Chapman, p. 9, pi. 2, fig. 5. 1930 Polymorphina lacrima Reuss; Cushman and Ozawa, p. 77, pi. 13, figs. 1, 2. 1930 Polymorphina gibba d’Orbigny; Hofker, p. 5, figs. 7-9. 1946 Globulina lacrima Reuss; Schijfsma, p. 66, pi. 7, fig. 2. 1951 Globulina lacrima Reuss; Visser, p. 241, pi. 4, fig. 7. 1957 Globulina lacrima Reuss; Hofker, p. 170, figs. 212, 213. Globulina lacrima subspliaerica (Berthelin) Text-figs. 1 c-j, 3 1880 Polymorphina subspliaerica Berthelin, p. 58, pi. 4, fig. 18. 1957 Globulina lacrima Reuss var. subspliaerica (Berthelin); Hofker, p. 171, figs. 214, 215. Description. The globular thick-walled smooth test shows little or no tendency to vary in shape. Smaller forms and early stages of the test show a tendency to be slightly elongated vertically. The curved sutures are flush with the surface of the test and rarely 3 A 716 PALAEONTOLOGY, VOLUME 5 TOM BARNARD: POLYMORPHIN1DAE FROM ENGLAND 717 show constrictions, so that the arrangement of the chambers is almost impossible to interpret. Occasional decorticated specimens show that there are few chambers, about five, constituting the test, and they are arranged irregularly about a vertical axis. Not only is the end-chamber large, making up one-half of the volume of the test, but it over- laps the earlier chambers. Generally the aperture is radiate and situated on a conical protuberance, but often the aperture becomes elliptical. Numerous peculiar forms occur as offshoots from the main stock and some of these are described below. Horizon. Zone of Belemnitella mucronata. Dimensions of hypotypes: Globulina lacrima, a: BM P44758. Height 1-14 mm., breadth 0-95 mm. (text-fig. 1 a). b: BM P44759. Height 1-06 mm., breadth 076 mm. (text -fig. 1 b). c: BM P44764. Height 1-14 mm., breadth 072 mm. (text-fig. Ik). G. lacrima subsphaerica, d: BM P44760. Height 0-76 mm., breadth 060 mm. (text-fig. lc). e\ BM P44761. Height 0-80 mm., breadth 0-53 mm. (text-fig. 1 d). f: BM P44762. Height 0-76 mm., breadth 0-46 mm. (text-fig. 1/). g: BM P44763. Height 0-64 mm., to extension 0-84 mm., breadth 0-38 mm. (text-fig. 1 j). Localities, a, b, g\ H. Attock's Pit, New Catton, Norwich, Norfolk. d, e,f\ Council’s Pit, Newmarket Road, Norwich, Norfolk. c: Earlham Limekiln, Dereham Road, Norwich, Norfolk. The development of the Globulina lacrima Reuss group (text-fig. 2) The writer considers that the large form G. lacrima Reuss, described above, is not the central root-stock of the group. A somewhat smaller, more abundant form, G. lacrima Reuss var. subsphaerica Berthelin, is considered to be the persistent and central form. This form is slightly elongated, but has the same general characters as G. lacrima Reuss, and ranges through the Upper Chalk. At certain horizons, as well as the abundant smaller tests, there occur specimens of G. lacrima Reuss, showing a tendency to become text-fig. 1. All figs. x90, except / (x 150). a, b, Globulina lacrima Reuss; H. Attock’s Pit, Norwich, Norfolk; Belemnitella mucronata Zone; normal large globular forms; a, BM P44758; b , BM P44759. c-j, Globulina lacrima Reuss var. subsphaerica Berthelin; Belemnitella mucronata Zone, c, d, i. Council’s Pit, Newmarket Road, Norwich, Norfolk; BM P44760, P44761, and P44762 respectively. j, H. Attock’s Pit, Norwich, Norfolk; BM P44763. c, d, common small variety; e-g, showing variation of aperture; h, broken wall to show thickness; i, fistulose hispid variety; j, smooth form with stellate fistulose chambers. k, Globulina lacrima Reuss; Earlham Limekiln, Dereham Road, Norwich, Norfolk; Belemnitella mucronata Zone; BM P44764. Large form showing extremely complicated fistulose end-chamber with numerous apertures, also a tendency for pustules to develop along parts of the test wall. l, Globulina lacrima Reuss, X 150. Quarry at Curfs (near Houthem), near Maastricht, Holland; Beds Md., Upper Maestrichtian ; BM P44771. The specimen shows an early globular stage, followed by an irregular end-chamber. This later chamber has been broken to enable the earlier apertures to be seen. The final aperture of the globular portion shows distinct signs of resorption, changing from the normal radiate aperture to a long regular slit, following the general surface of the test. 718 PALAEONTOLOGY, VOLUME 5 almost spherical and to increase in size. This form rarely gives rise to fistulose forms. One of these (text-fig. Ik) shows the large globular test of G. lacrima Reuss, with an irregular pustulose ornament over the initial chambers. Later a large irregular stellate outgrowth occurs, spreading down the test. This fistulose last portion of the test has numerous tube-like prolongations, at the ends of which are circular apertures which often have small but thick lips. These tube-like extensions may be arranged irregularly text-fig. 2. A diagrammatic representation of the variation and evolution of the Globulirta lacrima Reuss var. subsphaerica Berthelin group. over the surface, or placed along the stellate outgrowths. In both cases a wide coverage of the surface area is obtained. Many authors have stated that these fistulose outgrowths are only the last chamber; however, specimens have been obtained where several chambers are involved and the irregular portion is not just an outgrowth from the last chamber. Also in some forms the fistulose portion stretches down almost to the initial chamber, and there are con- nexions through the wall of the test to earlier chambers. In these forms there is often a resorption of the internal septa or chamber walls, so that the test is almost ‘unilocular’, except for small but regular parts of the original walls. The regularity of these ‘frag- ments’ suggests resorption rather than subsequent alteration. The fistulose globular forms occur as sporadic offshoots from the large Globulina lacrima Reuss stock, and occur at disconnected levels. TOM BARNARD: POLYMORPHINIDAE FROM ENGLAND 719 Throughout the longer history of GlobuJina lacrima subsphaerica, offshoots arise with several variations. For convenience these are divided into three groups: 1. Smooth test, with fistulose outgrowths with: ( i Lc? 1 r- text-fig. 1. Index maps of Chazy, Isle La Motte, and South Hero Island. JUNE R. P. PHILLIPS ROSS: CHAZYAN (ORDOVICIAN) BRYOZOA 729 text-fig. 3. Map of Isle La Motte showing collection localities. text-fig. 4. Map of South Hero Island showing collection locality. feet 730 PALAEONTOLOGY, VOLUME 5 acanthopores are a distinct morphologic feature, appears to be a divergent lineage from the main atactotoechid group. Jordcmopora appears to be a primitive member of the leptotrypellid group and Anaphragma may be a later Ordovician offshoot of this group. The main leptotrypellid stock is well defined in the Devonian, where it is represented abundantly in such assem- blages as those from the Traverse Group of Michigan (Duncan 1939) and the Hamilton Group of New York State (Boardman 1960). Acknowledgements. I express my sincere thanks to Dr. G. A. Cooper and Dr. R. S. Boardman of the United States National Museum for the loan of bryozoan specimens and to Dr. C. A. Ross, Illinois State Geological Survey, for helpful discussions on bryozoan taxonomy. I gratefully acknowledge financial support for this study by a grant from the National Science Foundation. Repository. Peabody Museum, Yale University (abbreviated to ypm). SYSTEMATIC DESCRIPTIONS Leptotrypellid group The microstructure of the zooecial walls was used by Boardman (1960, p. 51) to dis- tinguish the leptotrypellid group. The inner parts of the zooecial walls are composed of steeply inclined, distally sloping laminae which pass indistinctly into the amalgamate outer parts formed by adjacent zooecia. The amalgamate outer parts display distally convex laminae. Genus jordanopora gen. nov. Type species. Jordanopora heroensis sp. nov. Definition. Colonies are ramose or incrusting. Round zooecial openings are separated by wide, amalgamate laminate walls. In tangential sections the outer amalgamate parts of the zooecial walls are penetrated by very numerous small pores. Small mesopores are sparse between zooecia. In longitudinal sections the slender, crenulate, longitudinally laminate zooecial walls in the axial region pass into a narrow peripheral region of thickened zooecial walls. These thickened zooecial walls consist of laminae lying for a short distance parallel to the direction of the zooecial tube, then inclining steeply to the zooecial boundary. Near the zooecial boundary the laminae have a distally convex curvature and the boundary of adjacent zooecia consists of an intertonguing of these curved wall laminae. In the peripheral region the boundary is penetrated by small pores that have broadly curved, distally convex laminate wall structure. The laminae of the sparse diaphragms in the zooecial tubes enter the zooecial walls and follow the same pattern as other wall laminae. The numerous laminate diaphragms in the mesopores enter the zooecial walls in a similar manner. Occurrence. Chazyan of Chazy area, N.Y., Isle La Motte, Vt., and South Hero Island, Vt. Discussion. The wall structure in Jordanopora appears to be a forerunner of the more distinctive wall structure of Leptotrypella, in which the intertonguing distally convex laminae of the outer parts of adjacent zooecia are more clearly defined as a single unit than in Jordanopora. The steeply inclined laminae of the inner parts of the zooecial walls JUNE R. P. PHILLIPS ROSS: CHAZYAN (ORDOVICIAN) BRYOZOA 731 SOUTHWEST OF CHAZY NEAR TYPE SECTION LEGEND ). Test tetrahedral, spine length above 50 per cent., but not exceeding 100 per cent, of the test size, bases relatively narrow. Forma wenlockianum. The forms described as Veryhachium tetraedron var. wenlockia Downie 1959 from the Silurian of Britain are allocated to V. europaeum since the species V. tetraedron is invalid. The type and description are those given by Downie 1959 (p. 62). This forma differs from the holotype of V. europaeum by its distinct and restricted spine bases and from the British Permian forms by its greater spine length (up to approximately five times greater than the test dimensions). EXPLANATION OF PLATE 114 All figures X 1,000. Figs. 1-3. Veryhachium rhomboidium Downie. 1, Forma 3. 2, 3, Forma 4. All from sample B. Figs. 4-6. V. europaeum Stock, and Will. 4, 5, Forma 1. 6, Forma 2. All from sample A. Figs, 7-1 1 V. formosum Stock, and Will. 7, 8, Forma 1. 9-11, Forma 2. All from sample B. Fig. 12. Veryhachium sp. showing the presence of a small spine near the centre of the test. Sample A. Palaeontology, Vol. 5 PLATE 114 WALL and DOWNIE, Permian hystrichospheres D. WALL AND C. DOWNIE: PERMIAN HYSTRICHOSPHERES 783 Comparisons. The species is here restricted to forms whose tests have more or less straight sides. Inflated, subglobular forms are referred to V. ? irregulare f. subtetraedron Jekhowsky. Veryhachium formosum Stockmans and Williere 1960 Remarks. Forms allocated to this species from the British Permian differ from the holotype from the Devonian of Belgium in their shorter spine length and from V. ? riburgense f. regulare Brosius and Bitterli by their less inflated tests. They possess from five to rarely nine appendages but always maintain a triangular outline. Forma 1 (PI. 114, figs. 7, 8; text-fig. 1 q). Test more or less tetrahedral, with four apical spines and one additional spine on one face. Spine length from 50 to 100 per cent, of the test size, spine bases relatively narrow. Test c. 15 to 20 p. Forma 2 (PI. 1 14, figs. 9-1 1 ; text-fig. I/-). Test more or less tetrahedral, with four apical spines and two to four supplementary processes ornamenting the faces. Spine length less than the test size. Spine bases may be expanded. Test c. 15 p. Acknowledgements. The authors are indebted to the National Coal Board for supplying the sample from the Ash Hill Borehole and to Mr. G. S. Bryant of the Geology Department in Sheffield for technical assistance. Mr. Wall acknowledges a Shell International Oil Company Grant enabling him to do this work as part of a research project in micropalaeontology. REFERENCES brosius, m., and bitterli, p. 1961. Middle Triassic Hystrichosphaerids from salt-wells Riburg-15 and -17, Switzerland. Bull. Ver. Schweizer, Petrol. -Geol. u. -Ing. 28, 74, 33-49, 2 pi. deflandre, g. 1937. Microfossiles des silex cretaces. Part 2. Ann. Paleont. 26, 1-55, pi. 8-18. 1942. Sur les Hystrichospheres des calcaires siluriens de la Montagne Noire. C.R. Acad. Sci. Paris, 215, 475-6. 1945. Microfossiles des calcaires siluriens de la Montagne Noire. Ann. Paleont. 31, 41-75, pi. 1-2. 1947. Sur quelques micro-organismes planctoniques des silex jurassiques. Bull. Inst. Oceanogr. Monaco, 921, 1-10. deunff, j. 1954a. Sur un microplancton du Devonien du Canada recelant des types nouveaux d’Hystrichosphaerides. C.R. Acad. Sci. Paris, 239, 1064-6. 19546. Veryhachium, genre nouveau d’Hystrichospheres du Primaire. C.R. Soc. geol. France , 305-6. downie, c. 1959. Hystrichospheres from the Silurian Wenlock Shale of England. Palaeontology ,2, 56-71. I960. Deunffia and Domasia, new genera of hystrichospheres. Micropaleontology, 6, 2, 197-202, pi. 1. eisenack, A. 1958. Mikroplankton aus dem norddeutschen Apt. Neues Jb. Min., Geol., Palaeont. 106, 383-422, pi. 21-27. funkhauser, j. w., and evitt, w. r. 1959. Preparation techniques for acid-insoluble microfossils. Micropaleontology, 5, 3, 369-75. gilligan, a. 1918. The Lower Permian at Ashfield Brick and Tile Works, Conisborough. Proc. Yorks. Geol. Soc. 19, 289-97. jekhowsky, B. de 1961. Sur quelques Hystrichospheres Permo-Triassiques d’Europe et d'Afrique. Revue de Micropaleontologie, 3, 207-12, pi. 1-2. kara-murza, e. n. 1957. Hystrichosphaeridae du Cretace superieur et du Trias de l’Arctique sovie- tique. Inst. Rech. Scient. Geol. Arctique, Rec. Articles Paleont. et Biostrat. 4, 64-69. Leningrad. 784 PALAEONTOLOGY, VOLUME 5 sarjeant, w. a. s. 1959. Microplankton from the Cornbrash of Yorkshire. Geol. Mag. 96, 329-46, 1 pi. — — 1960. Microplankton from the Corallian Rocks of Yorkshire. Proc. Yorks. Geol. Soc. 32, 4, 18, 389-408. 1961. Microplankton from the Kellaways Rock and Oxford Clay of Yorkshire. Palaeontology, 4, 1, 90-118. staplin, f. l. 1961. Reef-controlled distribution of Devonian microplankton in Alberta. Ibid. 4, 3, 392-424, pi. 48-51. stockmans, F., and williere, Y. 1960. Hystrichospheres du Devonien beige. Senck. leth. 41, 1-11. valensi, L. 1953. Microfossiles des silex du Jurassique Moyen. Mem. Soc. geol. Fr. 68, 1-100, 16 pi. wilson, L. R. 1960. A Permian hystrichosphaerid from Oklahoma. Oklahoma Geol. Notes, 20, 7, 170. DAVID WALL CHARLES DOWNIE Department of Geology, Manuscript received 30 January 1962 University of Sheffield THE JURASSIC ECHINOID CIDARITES MONILIFERUS GOLDFUSS AND THE STATUS OF EUCIDARIS by G. M. PHILIP Abstract. The type specimen of the Jurassic cidarid Cidarites moniliferus Goldfuss, recently designated as type species of the genus Eucidaris Pomel 1883, is redescribed. The species is considered to be a typical member of the genus Stereocidaris Pomel 1883. As these two genera were published simultaneously, it is recommended that Eucidaris should be abandoned in favour of Stereocidaris. H. L. Clark (1926, p. 3) writes of the genus Eucidaris that it ‘is perhaps the best known and most universally accepted genus of Cidaridae. . . However, like many of the earlier echinoid genera, doubt exists as to the strict application of the name. Eucidaris was originally proposed by Pomel (1883, p. 109) as a section of the genus Cidaris, with the following unsatisfactory diagnosis: Eucidaris. Tubercles a col lisse: trois especes vivantes; presque toutes les especes tertiares; toutes les especes cretacees, mois une (20); quelques jurassique seulement (C. Morieri, Honorince, propinqua , marginata, monilifera, multipunctata ) ; la plupart des triasiques (7), Doderlein (1887, p. 42), who was the next writer to use the name, employed Eucidaris for the living species group embracing Cidarites metularia Lamarck, C. tribuloides Lamarck, and C. thouarsii Valenciennes, and it is in this sense that the genus has come to be used. The question was reviewed in a series of papers on the nomenclature of cidarid genera early this century (Bather 1908, 1908u, 1909; H. L. Clark 1908, 1909) where it was agreed that, as Gymnocidaris A. Agassiz 1863 (originally proposed for C. metularia ) was a homonym of Gymnocidaris L. Agassiz 1838, the name Eucidaris Pomel should be applied to the metularia species group. H. L. Clark (1909) designated C. metularia as type species of Eucidaris Pomel. Bather (1909) agreed with this designation, observing that ‘We may well suppose that the ‘trois especes vivantes’ of Pomel’s list were Cidaris metularia , C. tribuloides and C. thouarsi'. And here the matter has rested for fifty years with the genus Eucidaris Pomel uni- versally interpreted through C. metularia , a species not named in the founding of the genus, and so strictly not available for designation as type species. (Lambert and Thiery 1910, have been the only subsequent authors who have retained Cidaris s.st. for the metularia species group, taking this view from the misinterpretation of a pre- Linnaean figure given by Rumphius,/z ‘ 2 CO - Z w •>** 2 w 2 CO UTION NOIinillSNI_NVINOSHilWS S3IHVH8n LIBRARIES SMITHSONIAN INSTITUTION NOim CO —r T ^0 _ tO “ tO I CO O z O “ ■' o z _i z yuan LIBRARIES SMITHSONIAN INSTITUTION NOlinilXSNI NVINOSH1IINS SBIUVUan LI B R/ z f" z ro X) I- joEL ^*$31 ^ _ jz S5}g) XI Ti&y m ^ '4%^ m 5£ n '^T ^ m CO — CO _ CO \ ± (O tution NoiinniSNi NviNOSHiiws SBiavaan libraries Smithsonian institution Noun CO 2 ^ CO Z - < . 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