Editing Fossil localities - Capel Curig and Betws-y-Coed. Description of 1:25 000 sheet SH 75

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[[File:P992060.jpg|thumbnail|Plate 1 Caradoc Shelly fossils 1, 2 ''Plaesiomys multifida'' (Salter), x 1 Soudleyan Stage 3 ''Cyrtolites nodosus'' (Salter), x 1 Soudleyan Stage 4, 5 ''Dinorthis berwynensis'' (Whittington), x 1.5 Soudleyan Stage 6 ''Brongniartella minor'' (Salter), x 2 Soudleyan and Longvillian stages 7 ''Flexicalymene caractaci'' (Salter), x 1 Longvillian Stage 8 ''Broeggerolithus nicholsoni'' (Reed), x 1 Longvillian Stage 9 ''Lepidocoleus suecicus'' Moberg, a single plate x 4 Longvillian Stage 10, 11 ''Salopia globosa'' (Williams), x 2 Soudleyan Stage Outside the area of SH 75, some of these species range beyond the stages named here.]]

== Fossil localities ==

The faunas associated with the Ordovician sediments of the district are rarely well preserved and have generally been deformed. Many localities have yielded restricted faunas of uncertain age, but good faunas have been collected from others. A selection of the latter, with lists of determinations are given below. The graptolites were identified by Professor D. Skevington and the other fossils by Dr A. W. A. Rushton# [SH 7715 5740] By track 670 m E25°S of Swallow Falls Hotel (RV 3287–3360) Bryozoa (various forms of colony), ''Dalmanella modica ''Williams, ''Howellites antiquior ''(McCoy), ''Kjaerina?, ''rafinesquinid, ''Sowerbyella ''cf. ''musculosa ''Williams, tentaculitid, ''Broeggerolithus nicholsoni ''(Reed), ''Brongniartella minor ''(Salter), ''Flexicalymene planimarginata ''(Reed), ''Kloucekia ''cf. ''apiculata ''(McCoy), tetradellid ostracod, crinoid columnals. This assemblage occurs in the Gelli Grin Calcareous Ashes of the Bala District (Longvillian Stage), except for ''S. musculosa ''which is confined to the top of the Allt Ddu Mudstoncs (upper Soudleyan). The fauna is, however, less diverse.
# [SH 7865 5759] Crag 180 m S18°E of Penyr-Allt Ganol (RV 6249–6256) Bryozoan, ''Cremnorthis'' sp.'', ''dalmanellid [juv.], ''Dolerorthis'' sp.'', Howellites'' sp.'', Nicolella'' sp.'', Paracraniops'' sp.'', Reuschella?, Sericoidea'' sp.'', Skenidioides'' sp.'' ''[common], ''Sowerbyella'' sp.'',. ''gastropod and tentaculitid [fragments], ''Brongniartella'' sp.'' ''and calymenid [fragments], ''Lepidocoleus'' sp.'' ''This assemblage probably represents the Longvillian Stage but is not diagnostic.
# [SH 7852 5755] Crag 225 m S34°E of Penyr-Allt Ganol (RV 6257–6267) Bryozoa, ''Cremnorthis parva ''Williams [common], ''Dalmanella'' sp.'', Dolerorthis?'' [fragments],'' Howellites'' sp.'', Nicolella'' sp.'', Paracraniops?, Reuschella'' sp.'', Sericoidea'' sp.'', Skenidioides ''cf. ''costatus ''Cooper [common], ''Sowerbyella'' sp.'', Mimospira? ''[sinistral fragments], tentaculitid [fragments], calymenid and trinucleid [fragments], ''Lepidocoleus suecicus ''Moberg, crinoid columnals [circular]. The species present and the generic constitution of the fauna are reminiscent of the Gelli Grin Calcareous Ashes of the Bala District, of Longvillian age (Bassett and others, 1966).
# [SH 7573 5693] Forestry trackside, south of Ty-hyll (RV 6322–6361) Bryozoa [mainly encrusting], ''Dalmanella'' sp.'', Dolerorthis duftonensis ''(Reed) ''prolixa ''Williams, ''Howellites'' sp.'' ''[common], ''Leptestiina? ''[rare], ''Nicolella'' sp.'', Platystrophia'' sp.'', Sericoidea'' sp.'', Skenidioides'' sp.'', Sowerbyella'' sp.'' ''[very common], ''Modialopsis ''cf. ''pyrus ''Salter, tentaculitids, ''Brongniartella'' sp.'' ''[fragmentary], ''Chasmops ''cf. ''cambrensis? ''Whittington, ''Flexicalymene ''cf. ''caractaci ''(Salter), phacopid [fragment], ''Cerninella'' sp.'' ''[common]. ''Harperopsis'' sp.'' ''[common], ''Lepidocoleus ''cf. ''suecicus, ''crinoid columnals [pentagonal-rounded and circular]. This assemblage probably represents the Longvillian Stage.
# [SH 7531 5669] Trackside east of Bryn-y-Gefeiliau (RV 6444–6464) Bryozoa, ''Dalmanella'' sp.'' ''[small], ''Dolerorthis duftonensis ''(Reed) [several], ''Nicolella'' sp.'', Reuschella horderleyensis ''Bancroft s.I., ''Sericoidea'' sp.'', Skenidioides'' sp.'', Sowerbyella'' sp.'', ''triplesiid?, ''Cyclospira? ''[fragment], tentaculitid, ''Broeggerolithus? ''and cybelid [fragments], ''Flexicalymene'' sp.'', Lepidocoleus ''cf. ''suecicus, ''crinoid columnals [circular]. The fauna suggests the Longvillian Stage. The ''Dolerorthis ''includes valves resembling both ''D. duftonensis ''and ''D. duftonensis prolixa, ''both Longvillian subspecies.
# 6 [SH 7442 5788] Roadside exposure 400 m N13°W of Dol-gam (RV 6663–6724) Bryozoa, ''Dinorthis'' sp.'', Dolerorthis'' sp.'', Howellites?, Leptestiina ''cf. ''oepiki ''(Whittington), ''Nicolella'' sp.'' ''[abundant], ''Reuschella'' sp.'' ''[abundant], ''Sericoidea?, Skenidioides'' sp.'', Sowerbyella'' sp.'', Flexicalymene ''cf. ''caractaci ''[common], ''Platylichas ''cf. ''nodulosus ''(McCoy), trinucleid fragments, ''Lepidocoleus suecicus, ''primitiid ostracods, tentaculitids, crinoid columnals [pentagonal-rounded and circular]. By comparison with the faunas in the Bala area, a Longvillian age is suggested.
# [SH 7095 5789] Crags north of Llynnau Mymbyr (RV 6725–6754; 6953–6970) Bryozoan [stick-like], ''Dalmanella'' sp.'' ''[in siltstone], ''Dinorthis ''cf. ''berwynensis ''(Whittington) [in siltstone and sandstone], ''Howellites'' sp.'' ''[in siltstone], ''Macrocoelia'' sp.'' ''[in sandstone], ''Salopia ''cf. ''globosa ''(Williams) [in siltstone and sandstone]. The fauna is not diagnostic, but resembles the assemblages at the top of the Allt Ddu Mudstones of Bala (Soudleyan Stage).
# [SH 7865 5596] Forestry track north of Llyn Elsi (RV 7346–7373) Bryozoa [stick-like], ''Bicuspina spiriferoides ''McCoy [several], dalmanellids, ''Dinorthis'' sp.'' ''[costate], ''Howellites'' sp.'', Leptaena ''cf. ''ventricosa ''Williams, ''Rhactorthis?, Sowerbyella'' sp.'', Broeggerolithus ''[sp. indet.], pterygometopid [fragment], machaeridian [fragment], crinoid columnals. The fauna resembles that at the top of the Allt Ddu Mudstones and in the lower part of the Gelli-grin Calcareous Ashes at Bala (late Soudleyan or early Longvillian Stage).
# [SH 7434 5185] Crag on hillside south-east of Dolwyddelan (RV 6971–6986) ''Bicuspina'' sp.'', Dalmanella'' sp.'', Onniella?, Rhactorthis? ''[one specimen], ''Sowerbyella ''cf. ''musculosa?, Broeggerolithus? ''and calymenid [fragments], tetradellid, tentaculitid. ''Sowerbyella musculosa ''is known from the topmost Soudleyan of Bala; ''Rhactorthis is ''more suggestive of the Longvillian, but is poorly represented here.
# [SH 7155 5147] Crag north of Afon Lledr 290 m at 75° from Roman Bridge Station (RV 9690–9745). Bryozoa [stick-like and encrusting], ''Dalmanella'' sp.'' ''[cf. ''indica ''or ''modica], Howellites'' sp.'' ''[indet.], ''Sowerbyella ''cf. ''musculosa ''Williams [very abundant], tentaculitid, ''Broeggerolithus?, ''calymenid [fragments], ''Kloucekia? ''[small pygidium], crinoid fragments. Probably top of the Soudleyan Stage.
# [SH 76105119] to [SH 7610 5102] Crags between Bwlch-y-Groes and Pigyn Esgob (RV 7291–7321) Massive coarse siltstones yield: ''Bicuspina'' sp.'', ''dalmanellids, ''Macrocoelia'' sp.'' ''[large], ''Salopia globosa ''[and another form], asaphoid [fragment] and crinoid columnals. Cleaved fine siltstones yield: ''Bicuspina ''[fragment], ''Dalmanella'' sp.'', Dinorthis ''cf. ''berwynensis, Howellites'' sp.'', Macrocoelia ''[small], ''Cyrtolites nodosus ''(Salter), crinoid columnals [round and pentagonal-rounded]. Soudleyan or possibly Longvillian Stage.
# [SH 7800 5926] By roadside at Llyn Sarnau (RV 3475–3507) ''Amplexograptus arctus ''Elles & Wood, ''A. fallax ''Bulman, ''A.? perexcavatus ''(Lapworthl ''?Climacograptus antiques bursifer ''Elles & Wood, ''?C.brevis ''Elles & Wood, ''C.lineatus ''Elles & Wood, ''C.minimus ''(Carruthers), ''?Glyptograptus euglyphus ''(Lapworth), ''G.siccatzis ''Elles.& Wood, ''Orthograptus ''ex gr. ''calcaratus ''(Lapworth), ''O. ''ex gr. ''truncatus ''(Lapworth). Zone of ''Diplograptus multidens.''
# [SH 8000 5870] Roadside exposure, 0.5 km N of Cwmlanerch (DT 7732–7742) ''Amplexograptus'' sp.'', Climacograptus ?brevis, C. ''cf. ''brevis, C. lineatus, ?Glyptograptus euglyphus, Orthograptus ''ex gr. ''calcaratus, O. ''ex gr. ''truncatus, Pseudoclimacograptus ?scharenbergi ''(Lapworth). Zone of ''Diplograptus multidens.''

== [[Capel Curig and Betws-y-Coed. Description of 1:25 000 sheet SH 75#References|References]] ==

== [[Capel Curig and Betws-y-Coed. Description of 1:25 000 sheet SH 75#Glossary|Glossary]] ==

[[Category:Capel Curig and Betws-y-Coed, classical areas of British geology]]

[[Category:18. Wales]]