The Ordovician Rocks in the Cautley and Dent Districts of Westmorland and Yorkshire

Abstract

Summary The Ordovician inliers of the Cautley and Dent districts (Westmorland and NW. Yorkshire) expose an almost complete sequence of Ashgill beds—which form a better type sequence than that in Ash Gill, Coniston—underlain by the Pusgillian and part of the Onnian Stage of the Caradoc Series. Eight zones are recognized in the Ashgill Series, characterized by distinctive trilobite and brachiopod assemblages; faunal lists are appended. The term “Cautley Mud-stones” is introduced for strata from the Onnian Stage to the top of Zone 7. Marr’s “contemporaneous volcanic group” and “ mucronatus band of the Staurocephalus group” are renamed the “Cautley Volcanic Group” and “Cystoid Limestone” respectively. The term “Wilsey Beck Sandstone” is proposed for a rock unit that forms a useful marker horizon in Zone 2 of the Dent district. The approximate maximum thickness of Ordovician beds exposed is 2,100 feet (640 metres). Tentative correlations are made with Ashgill successions in Great Britain and abroad.

Arthrorhachis Hawle and Corda, 1984 (Agnostida) in the Prague Basin (Barrandian area, Czech Republic) revisited

“…Similarly, we suppose the specimens from Kazakhstan are conspecific with A. tarda (see Apollonov 1974). The differences in the relative glabellar and pygidial length between Bohemian and those from the British Isles determined as A. tarda (Ingham 1970, Dean 1971and Whittington 1968 were probably caused by different preservation, as discussed earlier by Ahlberg (1989). We also agree with Ahlberg (1989), that the specimen of Owen (1981, pl.…”

“…A palaeogeographical occurrence of the Arthrorhachis tarda (Barrande, 1846) and closely related species (A. tarda s.s.). The figured occurrences were compiled from these publications: 1) European peri-Gondwana, ATA (Armorican Terrane Assemblage): Bohemia (Barrande 1846(Barrande , 1852Hawle & Corda 1847;Pek 1977;Fatka & Pek 1999), Italy (Leone et al 2001); 2) Avalonia: South Wales (Dean 1971), North Wales (Whittington 1968), Northern England (Ingham 1970); 3) Baltica: Norway (Owen & Bruton 1980, Ahlberg 1989, Sweden (Ahlberg 1989), Denmark (Ahlberg 1989), Poland (Kielan 1960, Tomczykowa et al 1972; 4) Kazakhstania: Kazakhstan (Apollonov 1974), Uzbekistan (Abdullaev 1972); 5) Northern China (Zhou & Dean 1986, Zhou 1987. Map adapted after Fatka & Mergl (2009) and the discussion by Kříž & Steinová (2009). species of the lower part of the Králův Dvůr Formation, associated with graptolites typical for the middle to upper part of the formation (see Havlíček & Vaněk 1990, Havlíček & Fatka 1992, Havlíček 1998, namely Normalograptus angustus (Perner) and Dicellograptus cf.…”

Trilobite faunas of the Duncannon Group: Caradoc stratigraphy, environments and palaeobiogeography of the Leinster Terrane, IReland

“…ceryx is intermediate between the T. sagenosa species group and the early members of the T. moeldenensis group, most notably T. ceryx to which it is most closely similar (see Ingham 1970;Owen , 1987 for discussion of species groups in Tretaspis). The T. moeldenensis group (sensu stricto) first appeared in the late Caradoc of the Anglo-Welsh area, Scotland, Scandinavia and China with T. ceriodes and a similar age for the Raheen Formation in Co. Waterford is suggested by the closely allied T. ceryx.…”

Late Ordovician (Hirnantian) shelly fossils from New Zealand and their significance

“…It is a widespread species within rocks of Hirnantian age; for example, it is also known from the Sibumasu Terrane in the Panghsa-pye Formation of Burma (Cocks & Fortey 2002) and in the Wang Tong Formation of Thailand (Cocks & Fortey 1997). The other common contemporary species of Mucronaspis, which occurs within Gondwana, in the Cedarburg Formation of South Africa (Cocks & Fortey 1986), as well as in Europe, is M. olini, and the difference between that species and M. mucronata has been discussed in detail by Ingham (1977) and Fortey (in Cocks & Fortey 1986 prominent glabellar furrows are situated much nearer the rear of the cephalon than would be the case for both features in M. olini.…”