摘要:

Osmundaceous remains from the intertrappean beds of the Rajmahal Formation at Chunakhal, Rajmahal Hills, Bihar, are referred toToditesSeward,OsmundopsisHarris,PhyllopteroidesMedwell andCacumenCantrill & Webb.Osmundopsis, CacumenandPhyllopteroidesare recorded for the first time from India.Thinnfeldia chunakhalensisSah & Sukh-Dev is transferred toPhyllopteroides laevisCantrill & Webb. This is a significant Neocomian index species in eastern Australia and suggests a Neocomian age for this intertrappean bed at Chunakhal.

ISSN:0311-5518    

DOI:10.1080/03115519208619029

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

ISSN:0311-5518    

DOI:10.1080/03115519208619030

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Machaeridians are an enigmatic group of multisclerite-bearing benthic marine invertebrates, known from Lower Ordovician to Pennsylvanian rocks. They receive almost no attention, but are very common fossils, especially in faunas of Middle Ordovician to Early Devonian age. Evidence that machaeridians form a monophyletic group includes many shared derived morphological features of their sclerites, and their highly characteristic mode of sclerite formation. Machaeridian sclerites are calcitic, and feature an outer sclerite layer formed by marginal accretion, and an inner layer formed by serial addition of calcite elements in linear series radiating from the sclerite umbo. The class Machaeridia is understood herein to comprise the order Turrilepadomorpha Pilsbry, 1916, including the families Turrilepadidae Clarke 1896 and Plumulitidae Jell 1979, and the order Lepidocoleomorpha Schallreuter 1985, including the family Lepidocoleidae Clarke 1896. The latter family is unique in the possession of a dorsal tongue and groove hinge by which opposing sclerites of a given body segment articulated. All machaeridian species have distinct dextral and sinistral sclerite morphologies. All lepidocoleid species, and isolated members of some other families, are enantiomorphic, with some right-handed and some left-handed individuals. Recent classifications have united machaeridians with other problematic groups, including tommotiids, sachitids, and hercolepadids. Such proposed relationships have very weak evidential bases, and should be rejected.

ISSN:0311-5518    

DOI:10.1080/03115519208619031

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The classical Ordovician graptolite succession of Victoria has long been taken as standard for the region and widely used for subdivision and correlation of Ordovician sequences around the world. We review the Victorian succession and incorporate other Australian and New Zealand graptolitic sequences into an Australasian set of zones and stages. Thirty zones are recognized and defined, of which one (Ca4,Isograptus victoriae maximodivergens) is new and two (La1, Da4) each comprise two subzones. Several zones are redefined, but the previous zone notation has been retained. Nine stages are recognized (as previously) and defined, six (Lancefieldian, Bendigonian, Chewtonian, Castlemainian, Yapeenian, Darriwilian) in the Early Ordovician and three (Gisbornian, Eastonian, Bolindian) in the Late Ordovician; reference sections for each are nominated. The Bolindian stage contains 5 zones, here designated Bol-5. The Australasian stages are correlated internationally.

ISSN:0311-5518    

DOI:10.1080/03115519208619032

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

A species of alga is described from the Upper Ordovician successions of central New South Wales. Based on silicified specimens,Goobangia pyriformisgen. et sp. nov., comes from the Billabong Limestone on the Parkes Platform and the upper part of the Regans Creek Limestone of the Molong High. It resembles the pear-shaped dasycladaceanApidiumStolley but has a circlet of from 4 to 7 large pores on its upper surface and exhibits budding from one or more of these pores.

ISSN:0311-5518    

DOI:10.1080/03115519208619033

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

ISSN:0311-5518    

DOI:10.1080/03115519208619034

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor