SILURIAN CRYPTOSPORES AND MIOSPORES FROM THE TYPE WENLOCK AREA, SHROPSHIRE, ENGLAND by n. d. burgess and j. b. richardson Abstract. The earliest occurrence ofsculptured hilate cryptospores and miospores is near the base ofthe cf. protophanus-verrucatus Sporomorph Zone, now more accurately located within the lundgreni Graptolite Biozone in the type Wenlock area. Palynofacies studies indicate that this event is unrelated to changes in the depositional environment. All the Sheinwoodian sporomorphs are laevigate (six species) and have either a crassitate or patinate structure. The oldest known sculptured specimens of trilete miospores (two or three species) and hilate, crassitate/patinate cryptospores (four species) appear almost synchronously in the Homerian (upperpart oflundgreniGraptolite Biozone). Additional sculptured taxa (twospecies) appearin the later Homerian but there are no innovations in structure. In North Africa (Gondwana) a closely comparable sequence of structural and sculptural events occurs. Three groups of sporomorphs described from the Buildwas, Coalbrookdaleand lowerMuchWenlock LimestoneFormationsarepermanentlyfusedcryptospore tetrads (one species), hilate cryptospores derived from dyads (eight species), and trilete miospore (six species). Systematic descriptions of seventeen species in eight genera are provided. Two genera Laevolancis and Artemopyra threespeciesLaevolancisplicata Hispanaediscuswenlockensis,andArtemopyrabrevicosta andone , , , combination are new, and the genera Hispanaediscus and Dyadospora are emended. Wenlock sporomorphsalthough known from onlyafewstudiesprovideevidence fortheexistence ofearly land plants (Gray 1985) and hold a largely untapped potential forstratigraphical correlation (Richardson and McGregor 1986). Many of these assemblages contain mainly laevigate trilete miospores showing little diversity and have been obtained from poorly dated strata (Smith 1975; Colthurst and Smith 1977; Strother and Traverse 1979). Libyan assemblages are often superbly preserved (Richardson and Ioannides 1973) but although the sequence ofspore sculptural patterns is closely similar to that in the Welsh Borderland, and the succession is dated by graptolites, there are samples which may be either Lower Ludlow or Upper Wenlock based on the latter. In some of these cases sporomorph data from the present study support a Wenlock age. In contrast to North Africa, the geology of the type Wenlock area is well known (Bassett et al. 1975) and samples from higher parts of the sequence have yielded sporomorph assemblages of increasing diversity, although frequently spores are comparatively rare (1-20% of assemblage). Spores have been described from the type Wenlock area by Downie (1963), Richardson and Lister (1969), and Mabillard and Aldridge (1985) and from Dudley by Doming (1983). Most previous works consist solely of records of the miospore genus Ambitisporites, but Richardson and Lister (1969) described eight miospore taxa, including some questionable miospores now regarded as cryptospores, and sculptured tetrads in the Much Wenlock Limestone Formation (Wenlock Limestone). Sections in the typeWenlock area have been resampled (Text-fig. todetermine thediversity and 1) stratigraphical ranges of the sporomorph taxa and, as precisely as possible, the horizons where sporomorph events occur, in particular the first appearance of sculpture in ‘naked' cryptospores (i.e. those without envelopes) and in miospores. The advent ofsculptural types is considered to have biological as well as biostratigraphical significance (Richardson and Lister 1969; Gray 1985; IPalaeontology, Vol.34, Part3, 1991, pp.601-628, 2pls.| © The Palaeontological Association PALAEONTOLOGY, VOLUME 602 34 text-fig. 1. Lithostratigraphic and biostratigraphic position ofsamplescollected from the type Wenlock area, in relation to localities of Bassett et a/. (1975). Richardson 1985; Fanning et al. 1988). Such studies assist in attempts to understand the colonization ofthe land by plants because rocks ofthisagemaycontain abundant plant microfossils but few megafossils (Richardson and Ioannides 1973; Edwards and Fanning 1985; Gray 1985). ) BURGESS AND RICHARDSON: WENLOCK SPOROMORPHS 603 SAMPLING AND TECHNIQUES Reconnaissance samplingat Eaton Track and Harton Hollow Wood Quarry by Richardson and Lister(1969), and later by the authors with the Ludlow Research Group, revealed laevigate and sculptured sporomorphs at Graptohte locality 24 of Bassett et al. (1975), near the top ofthe Eaton Track Section. For this study a total offorty eight samples were collected from six sections covering a stratigraphical interval ofc. 240m (Table 1 from basal Sheinwoodian (basal centrifugus Graptolite Biozone) to the late Homerian (lower part of the ludensis Graptolite Biozone) but excluding the upper c. 20 m of the Much Wenlock Limestone Formation. However, the uppermost part of the section has been sampled independently by both authors in the type Ludlow Area and so far has not yielded any new taxa. Details on the stratigraphy ofthe type Wenlock Area sections (except for Hughley Brook) are in Bassett et al. (1975). table 1. Locality and horizon of the sections studied Section Grid reference Formation Hughley Brook c. 400 m SW ofGippols Farm SO 58009920 Buildwas Ticklerton Brook SO48589042 Coalbrookdale Rushbury SO 51329173- Coalbrookdale SO 51329168 Lakehouse Brook SO 51399164 Coalbrookdale Rushbury Pack Track SO 51369146- Coalbrookdale SO 51679123 Eaton Track SO 50049001- Coalbrookdale (Farley SO 50509010 Member)-Much Wenlock Limestone Harton Hollow Wood SO48148788 Much Wenlock Quarry Limestone Samples were all fine-grained buff to olive-green calcareous siltstones and silty limestones. Palynomorphs were extracted and prepared for light microscope observation using standard techniques: HC1-HF-HC1 acid treatment followed by zinc bromide solution (S.G. 2-0) heavy mineral separation. Organic residues were washed with distilled water between HC1 and HF treatment to remove residual calcium ions and to reduce the formation ofcalcium fluoride and related compounds during HF treatment. Residues were sieved through a 10/um sieve, dried on coverslips, mounted in ‘Elvacite’ mounting medium, and studied in normal transmitted light and Nomarski Interference using a Zeiss Photomicroscope. Photomicrographs were taken on Ilford FP4 film. From each sample 30 g ofrock was processed and a measured amount ofthe residue from a known mass ofrock mounted ona slide. Palynomorphs were then counted from a proportion ofthe slideand from this the absolute percentage per gram ofsample was calculated for prasinophycean ‘phycomata' (Tappan 1980) and each acritarch, cryptospore and miospore group. Palynomorph counts were made under oil at x 1000. SYSTEMATIC PALAEONTOLOGY ThelastdecadehasseenanumberofreportsshowingthatUpperOrdovician andSilurian stratacontainspore- like microfossils in association with trilete miospores (Strother and Traverse 1979; Miller and Eames 1982; Gray 1985; Johnson 1985; Hill et al. 1985; Richardson 1988). We group these atypical spores (cryptospores sensu Richardson et al. 1984; Richardson 1988) into two major categories which are morphologically distinct and which may reflect macroplant groups and their evolution. In the descriptions below the terminology of Grebe (1971) is used to describe all sporomorphs, included cryptospores, but we have used the term muri for sinuous, sometimes anastomosing, ridges, whether or not they form a reticulum. The stratigraphical distribution refers to the range within this study. Sporedimensionsaregiven as themaximum diameterin polarcompression unlessstated otherwise, with the PALAEONTOLOGY, VOLUME 604 34 minimum and maximum ofthe range presented and themean in brackets. Figured specimens are stored in the Palynology Section, Palaeontology Department, British Museum (Natural History), London and have the prefix FM. Specimen co-ordinates are from a Zeiss Photomicroscope III no. 2562 housed in the Department. All specimens are also located by means of standard England Finder co-ordinates, and are ringed using a permanent red pen. Anteturma cryptosporites Richardson et al., 1984 1. 1Permanently fused cryptospore tetrads ' This group comprises tetrads and dyads which are not found separated into their individual components and which we therefore believe are ‘permanently’ fused. Such forms are abundant in the lower Llandovery where well-preserved specimens are enclosed within variously sculptured envelopes (Strother and Traverse 1979; Miller and Eames 1982; Gray 1985, 1988; Johnson 1985; Burgess 1987). Occasionally individual specimens occur with poorly preserved proximal faces which may represent fragmented tetrads (Richardson 1988). Genus tetrahedraletes Strother and Traverse, 1979 Type species. Tetrahedraletes medinensis Strother and Traverse, 1979. Tetrahedraletes medinensis Strother and Traverse, 1979 Plate I, figs 12 and 13 Figuredspecimens. FM 156, PI. 1, fig. 12, slide S24/3, 040 1210; FM 157, PI. 1, fig. 13, slide S24/6 060 1240; both specimens from sample G 5, Hughley Brook, lower Buildwas Formation. EXPLANATION OF PLATE 1 All figures x 1000. Fignso:1 -F33.2/A3r/t4e)m,opsyarmaplbereEviTco7sat,a uspp.penrovC.oaI.lbDryoaodk;daFleMF1o4r7ma(tsliiodne,GlLu2n2d/grIencio-Gorrapdto0l6i0te10B3i0o;zoEnneg.la2,ndFFMind1e48r (slide GL24/26 co-ord 200 1110; E.F. no: U40/4 U41/3), sample ET 7c, upper Coalbrookdale Formation, nassa Graptolite Biozone. 3, FM 146, holotype (slide ET 9A/4co-ord 165 1300; E.F. no: R60), sample ET 10, Farley Member, nassa Graptolite Biozone. Figs 4-9. Hispanaediscus wenlockensis sp. nov. 4, FM 150 (slide GL24/23 co-ord 030 1263; E.F. no: C56/2), sample ET 7c, upper Coalbrookdale Formation, nassa Graptolite Biozone. 5, Proximal view showing radial muri;FM 151 (slide GL24/5 co-ord 130 1055; E.F. no: N35/3), sample ET 7c, upperCoalbrookdale Formation, nassa Graptolite Biozone. 6, Distal view showing verrucae; FM 149 (slide GL24/13 co-ord 100 1290; E.F. no: K59/4), sample ET 7c, upper Coalbrookdale Formation, nassa Graptolite Biozone. 7, Dyad; FM 153 (slide ET 9A/1 co-ord 090 1365; E.F. no: J67/2), sample ET 10, Farley Member, nassa Graptolite Biozone. 8, FM 152, holotype; proximal view (slide GL 24/24 co-ord 055 1205; E.F. no: E50/4 F50/2), sample ET 7c, upper Coalbrookdale Formation, nassa Graptolite Biozone. 9, Holotype, FM 152; distal view. Figpsro1x0imaanldhIil1.umA;rtFemMop1y5r4a(sspl.ideA.ET10,1P6/r5oxciom-aolrdsu0r7fa8ce10w8i8t;hEr.aFd.ialnom:urHi38a/n2)d,msuarmupslemaErTkin15g, bloouwenrdaMruycohf Wenlock Limestone Formation, ludensis Graptolite Biozone. 11, Specimen showing muri on proximal surface and smooth distal surface; FM 155 (slide ET 16/8 co-ord 144 1050; E.F. no: 034/4 035/3), sample ET 15, lower Much Wenlock Limestone Formation, ludensis Graptolite Biozone. Figs 12 and 13. Tetrahedraletes medinensis Strother and Traverse 1979. 12, FM 156 (slide S24/3 co-ord 040 G FM 1210; E.F. no: E53), sample 5, Buildwas Formation, centrifugus Graptolite Biozone. 13, 157 (slide S24/6 co-ord 060 1240; E.F. no: G54/1/3), sample G 5, Buildwas Formation, centrifugus Graptolite Biozone. Figs 14 and 15. hilate cryptospore type 1. 14, Sculptured distal surface; FM 158 (slide GL24/7 co-ord 100 1070; E.F. no: K36/4), sample ET 7c, upper Coalbrookdale Formation, nassa Graptolite Biozone. 15, Smooth ‘proximal’ surface of FM 158. PLATE 1 BURGESS and RICHARDSON, Wenlock cryptospores 606 PALAEONTOLOGY, VOLUME 34 Description. Laevigate obligate tetrahedral tetrads, subcircular to circular in outline, preserved in many compressional forms relating to the degree ofrotation from an apical view prior to compression. Within the tetrads individual ‘spores’ have a subtriangular to subcircular equatorial outline, and unfused equatorial crassitudes 1-5/;m wide. Distal exine 1-2pm thick and usually invaginated. Dimensions. Tetrads 30(37)52pm in diameter (100 specimens measured from sample G 5; Text-fig. 2). text-fig. 2. Size frequency distribution ofa hundred Tetrahedraletes medinensis (Strother and Traverse, 1979) froGmraspatmoplilteeGBi5o,zoHnueg)h;lexy=B3r7o-o3kpm(.centrifugus Distribution. Throughout the Wenlock, basal Sheinwoodian to late Homerian Stages, centrifugus to ludensis Graptolite Biozones. Comparisons. Specimens of Tetrahedraletes medinensis recovered in the Wenlock (Text-fig. 2) are larger than those from the Rhuddanian ofthe type Llandovery area (Burgess 1991) but are similar in size to those from the Llandovery of North America (Pratt et al. 1978; Strother and Traverse 1979; Miller and Eames 1982; Johnson 1985). 2. Hilate cryptospores Sporomorphs in this group are alete, hemispherical in equatorial view, have a thin proximal surface (hilum) and an equatorial thickening. In many cases they are seen to be derived from loosely attached dyads and as all have the same basic structure they are probably all derived from dyads. Genus laevolancis gen. nov. Type species. Laevolancis Archaeozonotriletes divellomedium (Chibrickova) comb. nov. ( ) Diagnosis. Alete proximally hilate cryptospores, originally elliptical to hemispherical in equatorial view with an equatorial to subequatorial crassitude surrounding the hilum; exine laevigate. Derivation ofname. Latin laevigatas, smooth; lands plate or dish. , Remarks. These cryptospores are occasionally seen as loosely attached dyads. Discussion. The genus Gneudnaspora Balme (1988) includes similar spores but is not used here because the Australian spores may be trilete, monolete or alete. The Wenlock spores are all alete and many, ifnot all, arederived from dyads. Consequently we have erected a new genus Laevolancis BURGESS AND RICHARDSON: WENLOCK SPOROMORPHS 607 to accommodate the alete forms in Balme’s genus and other alete species of similar structure with a laevigate exine. Laevolancis divellomedium (Chibrickova) comb. nov. Plate 2, figs 4 and 6. 1959 Archaeozonotriletes divellomedium Chibrickova, p. 65, pi. 9, fig. 4. 1966 Hispanciediscus bernesgae Cramer, p. 82, pi. I, fig. I ; text-fig. 2, figs 2 and 1 1. 1968 Spore no. 2651, Magloire, pi. 1, fig. 6. 1969 ?Archaeozonotriletes cf. divellomedium Chibrickova; Richardson and Lister, p. 238, pi. 43, fig. 12. 1973 ?A. cf. divellomedium Chibrickova; Richardson and Ioannides, p. 280, pi. 8, figs 10 and 1 1. 1974 Zonaletes (?) divellomedium (Chibrickova); Arkhangelskaya, pi. 6, figs 3 and 4. 1974 ?A. divellomedium Chibrickova; McGregor, pi. I, figs 35 and 40. 1978 Hispanciediscus sp., McGregor and Narbonne, p. 1296, pi. 1, figs 20-22. 1979 ‘Smooth-walled inaperturate spore’, Strother and Traverse, p. 14, pi. 12, fig. 9. 1984 ?Stenozonotriletes irregularis McGregor, p. 37, pi. 1, fig. 26. 1986 Tholisporites divellomedium Turnau, p. 349, pi. 2, fig. 12. 1980 Zonaletes (?) divellomedium (Chibrickova) Arkhangelskaya, pi. 5, fig. 34. 1988 Gneudnaspora divellomedium (Chibrickova) Balme, p. 125 [partim], pi. 3, figs 1-7. Holotvpeandtypelocality. Chibrickova, 1959,prep. 977,collectionsoftheGorno-Geological Institute, Bashkir Filial, Academy ofSciences, USSR; Takata Beds, Emsian. Figured specimens. FM 163, PI. 2, fig. 4, slide S24/3, 145 1290, sample G5, Hughley Brook, Buildwas Formation; FM 164, PI. 2, fig. 6, slide ET 8/5, 133 1265, sample ET 6, Eaton Track, upper Coalbrookdale Formation. Diagnosis. A Laevolancis with a rigid wall and a 1-5)4 pm wide subequatorial crassitude. 1( Description. Cryptospores occasionally preserved in loosely attached dyads in a variety of compressional morphologiesbutareusuallyseparated. Separatedspores: ambsubcircular, oroccasionallycircular, specimens frequently tipped, originally roughlyhemispherical inequatorial viewwith +flattened proximal polararea. An equatorial to subequatorial crassitude surrounds the proximal hilum; hilum flattened to concave in equatorial view, laevigate, occasionally folded, or ruptured, optically appears thinner than the distal exine; distal exine laevigate c. 2pm thick. Dimensions. Maximum diameter 30(38)49pm, minimum diameter 18(30)38 /an (30 specimens measured from sample G 5, Flughley Brook, Buildwas Formation). Distribution. Present and often common throughout the sequence, Buildwas to Much Wenlock Limestone Formations; basal centrifugus to lower ludensis Graptolite Biozones. Comparisons. The size range of Chibrickova’s specimens (35-50 pm; Chibrickova 1959) overlaps with that of the Wenlock specimens. Balme’s specimens from the Devonian Gneudna Formation (Balme 1988) also overlap but are mostly larger (44-68 pm) otherwise the alete forms described by ; Balme are identical (J.B.R., examination of the Australian material). Hispanciediscus bernesgae Cramer, 1966 is regarded as synonymous but the genus Hispanaediscus is restricted herein to verrucate hilate cryptospores similar to the type species. Laevolancisplicata sp. nov. Plate 2, fig. 8 Holotype and type locality. FM 167; PI. 2, fig. 8; slide Rush S14/5, 170 1150; sample R 17, Rushbury Pack Track (Text-fig. 1; Tabic 1), Coalbrookdale Formation, late Wenlock lundgreni Graptolite Biozone. 608 PALAEONTOLOGY, VOLUME 34 A Diagnosis. Laevolancis with thin, often folded, walls. Derivation ofname. Latin plicatus, folded. Description. Cryptospores occasionally preserved in loosely attached, often partially separated, dyads but spores are most frequently found separated as single grains. Amb sub-circular to circular; distally slightly convex in equatorial view. Crassitude equatorial to sub-equatorial, 05-1-5 pm wide, surrounds a proximal hilum; proximal hilum usually concave, laevigate and frequently folded. Distal exine c. I pm thick, laevigate. Dimensions. Maximum diameter 22(27)35 pm, minimum diameter 14(21)27pm (30 specimens measured from sample ET 7c); Eaton Track Section, Coalbrookdale Formation. Distribution. Present throughout the sequence, Buildwas to Much Wenlock Limestone Formations; basal centrifugus to lower ludensis Graptolite Biozones. Comparisons. Laevolancis divellomedium (Chibrickova) comb. nov. is larger, more inflated distally and has a thicker, more rigid wall (c. 2 pm). Many ofthese spores are separated from dyads ofthe genusDyadospora(StrotherandTraverse, 1979)emend, and possiblysolely fromD. murusattenuata. Genus hispanaediscus (Cramer) emend. Type species. Hispanaediscus verrucatus Cramer, 1966. Emended diagnosis. Alete proximally hilate cryptospores; originally elliptical to hemispherical in equatorial view; equatorial to sub-equatorial crassitude surrounding the hilum. Flilum laevigate, or EXPLANATION OF PLATE 2 All figures x 1000. FM Figs 1-3, 5. Dyadospora murusdensa (Strother and Traverse) emend. 1, 159 (slide Tick Sl/7 co-ord 063 1209; E.F. no: F51/1/3), sample T 1, lower Coalbrookdale Formation, ellesae Graptolite Biozone. 2, Partially separated specimen with pyrite damage, FM 161 (slide Rush S 10/8 co-ord 200 1204; E.F. no: U50/4), sample R 14, upper Coalbrookdale Formation, lundgreniGraptolite Biozone. 3, FM 160 (slide ET 5A/5co-ord 152 1053; E.F. no: P35/3),sample ET3, upperCoalbrookdale Formation, lundgreniGraptolite Biozone. 5, partially separated specimen; FM 162 (slide Rush S10/1, co-ord 070 1220; E.F. no: G52/2/G53/1), sample R 14, upper Coalbrookdale Formation, lundgreni Graptolite Biozone. Figs 4 and 6. Laevolancis divellomedium (Chibrickova) comb. nov. 4, FM 164, holotype (slide ET 8/5 co-ord 133 1265; E.F. no: N56/4/N57/3), sample ET 6, upper Coalbrookdale Formation, lundgreni Graptolite Biozone. 6, FM 163 (slideS24/3co-ord 145 1290; E.F. no: P59/2/P60/1), sampleG 5, Buildwas Formation, centrifugus Graptolite Biozone. Figs 7 and 9. Dyadospora murusattenuata (Strother and Traverse) emend. 7, FM 165 (slide GL24/25 co-ord 098 1202; E.F. no: K50), sample ET 7c, upper Coalbrookdale Formation, nassa Graptolite Biozone. 9, FM 166 (slide Rush S10/8 co-ord 153, 1204: E.F. no: P50), sample R 14, upperCoalbrookdale Formation, lundgreni Graptolite Biozone. Fig. 8. Laevolancisplicata sp. nov. FM 167, holotype (Rush S14/5 co-ord 170 1150: E.F. no: Q44), sample R 17, upper Coalbrookdale Formation, lundgreni Graptolite Biozone. Figs 10and 11.cf. Hispanaediscussp. A. 10, FM 168(slide ET 16/5co-ord090 1140; E.F. no: J44/1/2), sample ET 15, lower Much Wenlock Limestone Formation, ludensisGraptolite Biozone. 1 1, FM 169 (slide ET 16/2 co-ord 160 1210; E.F. no: Q51/3), sample ET 15, lower Much Wenlock Limestone Formation, ludensis Graptolite Biozone. Figs 12 and 13. Hispanaediscus verrucatus (Cramer) emend. 12, FM 170 (slide Rush S14/5 co-ord 065 1040: E.F. no: F33), sample R 17, upper Coalbrookdale Formation, lundgreni Graptolite Biozone. 13, FM 171 (slide ET 8/6 co-ord 017 1350; E.F. no: A65/2), sample ET 6, upper Coalbrookdale Formation, lundgreni Graptolite Biozone. PLATE 2 BURGESS and RICHARDSON, Wenlock cryptospores 3 \ PALAEONTOLOGY, VOLUME 610 34 with radial and/or randomly orientated muri/folds. Distal exine ornamented with verrucae and or muri. Comparison. Artemopyra gen. nov. has the same structure and radial proximal muri/folds, but is distally laevigate, apiculate or spinose. Remarks. Hilate cryptospores in Hispanaediscus are occasionally seen as loosely attached dyads. This genus was originally erected by Cramer (1966) for alete palynomorphs with laevigate, verrucate/murornate and foveolate sculpture. The type species is verrucate and we have restricted the genus to forms with verrucate distal sculpture where the proximal exine is not markedly thinner than the distal and included species with proximal sculpture. Hispanaediscus verrucatus (Cramer) emend. Plate 2, figs 12 and 1 1966 Hispanaediscus verrucatus Cramer, p. 82, pi. 2, fig. 7 [partint]. non fig. 2. 71969 cf. Synorisporites verrucatus Richardson and Lister, pi. 40, fig. 13. 1973 cf. Synorisporites verrucatus Richardson and Lister; Richardson and Ioannides, p. 278, [partial pi. 6, figs 17, 18, 20, non pi. 6, fig. 19. Holotype. Cramer, 1966, pi. 2, fig. 7; F: 22354-5-2. San Pedro Formation, nearValporquero, Leon, northwest Spain. Probably oflate Silurian age. Figured specimens. FM 170, PI. 2, fig. 12, slide Rush 13/14, 065 1040, sample R 16, Rushbury Pack Track, Coalbrookdale Formation; FM 171, PL 2, fig. 13, slide ET 8/6, 017 1350, sample ET 6, Eaton Track, upper Coalbrookdale Formation. Emendeddiagnosis. An Hispanaediscuswith asmooth, diaphanous hilum and verrucate - murornate distal sculpture. Description. Hilate cryptospores probably derived from loosely attached, partially separated, dyads, but all specimens seen are single grains. Amb sub-circular to circular, originally distally hemispherical in equatorial viewand flattened proximally. Distal exinemore or lessconvex, c. 1 pmthick, sculptureconsistsmainlyoflow verrucae and/or muri 1-5 pm wide, c. I pm high and 0-5-3 //m apart. The groups of fused elements may coalesce into longer occasionally convolute and anastomosing muri. Dimensions. Maximum diameter 23(28)32/an, minimum diameter 22(25)30pm (15 specimens measured). Distribution. Upper Coalbrookdale Formation, Farley Member, and Much Wenlock Limestone Formation; upper lundgreni to lower ludensis Graptolite Biozones. Comparisons. Some ofCramer’s specimens appear identical to those from the Wenlock ofthe type area and Wenlock-Ludlow ofNorth Africa. The spores from England, Spain and North Africa all have size ranges less than 35 //m, and means ofbetween 24 and 28 pm. H. wenlockensis is larger and has proximal radial muri. Remarks. Cramer’s material appears to include trilete spores with a more triangular outline, similarly the material described by Richardson and Ioannides includes tetrads with comparable sculpture. Herein H. verrucatusis restricted to alete hilatecryptospores with acircularorsubcircular amb.