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Conodonts from the Densmore Creek Phosphate Bed at the base of the Maplewood Shale in Irondequoit, New York, include Panderodus unicostatus, Pranognathus tenuis, and Icriodella discreta. The taxa Ozarkodina cf. Oz. hassi, Pranognathus tenuis, Oulodus panuarensis, Panderodus unicostatus, Panderodus recurvatus, and Pseudooneotodus beckmanni were recovered from the overlying Budd Road Phosphate Bed at the base of the Reynales Limestone near Lockport, New York. The specimens from both beds are indicative of the Pranognathus tenuis Zone, which correlates to the lower to middle Aeronian, and indicate that the Budd Road Phosphate Bed at Lockport was deposited in a more offshore environment than the Densmore Creek Phosphate Bed at Irondequoit. [ABSTRACT FROM AUTHOR]

Despite the crucial role of epibenthic primary producers (cyanobacteria, green and red algae), no diversity curves for calcimicrobes and calcareous algae are available to assess the pyramiding paleoecology characterizing the Ordovician biodiversification episode. A total of 24 taxa of calcimicrobes and calcareous algae are identified from a Dapingian to lower Katian succession of carbonate sedimentary rocks exposed at the Leyayilitag ridge, Bachu Uplift, Tarim Basin, northwest China. Calcimicrobes (14 taxa), Dasycladales (seven taxa), Bryopsidales (one taxon), and Cyclocrinales (two taxa) contribute to five distinct taphocoenoses characterizing a suite of carbonate mounds. In stratigraphic order, these are calathid sponge mounds, algal calcimicrobial mounds, algal mounds, algal reefs, and calcimicrobial mounds. Within the lower Katian Belodina confluens Zone, the diversity increases substantially from around 5 to more than 20 taxa per 2 Ma. This increase in diversity is based on new calcimicrobes ( Bija, Ortonella, Garwoodia, Hedstroemia, Rothpletzella, Phacelophyton, Rauserina) and the diversification of Dasycladales and Cyclocrinales. By comparison, the global diversity of calcimicrobes and calcareous algae (derived from literature data) started to increase earlier, namely within the late Darriwilian Pygodus serra Zone (offset of about 4 Ma). This offset might be due to the peculiar lithology of the Sandbian Tumuxiuke Formation (condensed section of red nodular limestones bounded by disconformities). However, a similar temporal offset is recorded for calathid sponge mounds; therefore, the Tarim tectonic microplate (Tarim Block) might display an endemic-anachronistic character. The diversity curves of Ordovician benthic primary producers (calcimicrobes, calcareous algae) are similar to those recorded by some fossil groups, in particular eleutherozoan echinoderms. [ABSTRACT FROM AUTHOR]

The Late Cretaceous marine gastropod Sycodes glabra (Shumard, 1858) from the northeast Pacific has been poorly known because the type, which was never figured, was lost in a fire in 1892, and the type locality was very poorly located. A neotype is selected from specimens collected by the early Canadians, geologist J. Richardson and eminent British Columbian naturalist Dr. C.F. Newcombe. Newly discovered material, as well as museum specimens, provide fundamental geologic and paleontologic information. The number of available specimens is 19, and nearly all are from submarine-fan deposits in the Upper Cretaceous Nanaimo Group exposed along the southeastern-coastal region of Vancouver Island, British Columbia, and on Big Sucia Island, northwestern Washington State, with nearly half of the specimens from the latter locale. A single specimen is from northern California. This present study better establishes the type locality for S. glabra and documents this name as the senior subjective synonym of ? Ficus cypraeoides Gabb, 1864. The geologic range of S. glabra is early Campanian ( Submortoniceras chicoense ammonite Zone) to early late Campanian ( Metaplacenticeras cf. pacificum ammonite Zone). Sycodes seems to be a monotypic genus, but Pyrula ( Protopirula) capensis Rennie, 1930, from mid-Santonian to lower Campanian strata in South Africa, might be congeneric. Sycodes is questionably assigned herein to the family Ficidae Meek, 1864, and could be the earliest known ficid. [ABSTRACT FROM AUTHOR]

The oldest Foliomena fauna was, until now, known from the middle-upper Miaopo Formation ( Nemagraptus gracilis Biozone, lower Sandbian, basal Upper Ordovician) of South China. In this study, the oldest record of the fauna is set back to the latest Darriwilian (upper Hustedograptus teretiusculus Biozone), represented by Foliomena jielingensis and some typical constituents of the Foliomena fauna from the basal Miaopo Formation at Jieling, northern Yichang, western Hubei Province, central China. The Miaopo Formation is characterized by its organic-rich dark-grey shale facies, unique in its localized distribution on the Yangtze Platform, and distinguished by its rich and diverse benthic and graptolitic faunas. This suggests an origin of the Foliomena fauna in periodically oxygen-starved local depressions on the Yangtze Platform during the Middle-Late Ordovician transition. [ABSTRACT FROM AUTHOR]

Species of Deiracephalus Resser, 1935, are rare elements in most Guzhangian (upper Marjuman) trilobite faunas of Laurentian North America, and are characterized by striking cephalic spinosity that includes very long genal and occipital or preoccipital glabellar spines. Almost all previous reports of the genus have assigned sclerites to two species, Deiracephalus aster (Walcott, 1916) and Deiracephalus unicornis Palmer, 1962. However, new material from the Shallow Bay Formation of western Newfoundland and restudy of type material from the southern Appalachians show that as many as eight species are present, although not all of them are sufficiently well known to be formally named. Deiracephalus aster and D. unicornis are restricted to their respective holotypes from the Conasauga Formation of Alabama; new species from the Shallow Bay Formation are Deiracephalus narwhali, Deiracephalus rhinocerotis, Deiracephalus dynastoides, and Deiracephalus phanaeus. Deiracephalusunicornis, D. narwhali, D. rhinocerotis, and a poorly known species from Nevada all possess preoccipital glabellar spines, and form an informal "unicornis group" of species. This group occurs high in the traditional Crepicephalus Zone (latest Guzhangian) and offers a potentially important means of biostratigraphic correlation. Species with occipital spines are older than the unicornis group and extend down into the Cedaria Zone as used traditionally in North America. [ABSTRACT FROM AUTHOR]

Hall Peninsula, located on southeastern Baffin Island, Nunavut, hosts the newly discovered Chidliak kimberlite province. Presently, this area lacks Phanerozoic sedimentary cover, except for the unconsolidated glacial deposits; however, Late Ordovician and Early Silurian microfossil conodonts have been recovered from carbonate xenoliths preserved in the Late Jurassic - Early Cretaceous kimberlites. Over 1300 conodont specimens were recovered, among which 32 species representing 23 genera are recognized, with four elements indeterminate. The well-preserved conodont faunas provide reliable evidence on the Hall Peninsula for ( i) reconstructing the Lower Paleozoic stratigraphic units, including the Upper Ordovician Frobisher Bay, Amadjuak, Akpatok, and Foster Bay formations, and the Lower Silurian Severn River Formation, ( ii) estimating a total of 270-305 m in thickness of Lower Paleozoic sedimentary cover prior to the emplacement of the kimberlites, ( iii) tracing the erosion history after the emplacement of the kimberlites, and ( iv) calculating a minimum erosion rate of 2 m/Ma. The conodonts have a wide range of conodont Color Alteration Index (CAI) values between 1.5 and 8, which is the largest range recorded in any known suite of xenoliths entrained in kimberlites. [ABSTRACT FROM AUTHOR]

A Darriwilian (late Middle Ordovician) brachiopod fauna from the Lower Formation of the Chiatsun Group at Jiacun, northern Nyalam, southern Tibet, consists of ten brachiopod species, forming a distinct Aporthophyla- Paralenorthis Association. Its taxonomic composition is typical of the Aporthophyla Fauna that occupied lower BA2 to upper BA3 benthic environments on sandy lime mud substrates. The occurrence of Paralenorthis in southern Tibet is confirmed for the first time, represented by P. costata sp. nov. Numerical analyses ( PCA and CA) of 18 Darriwilian brachiopod faunas from ten palaeoplates or terranes indicate that: (1) the Aporthophyla Fauna was confined to a specific latitudinal belt although it had a wide lateral distribution from the large palaeocontinents of Gondwana to Laurentia; (2) the Saucrorthis Fauna, a typical late Middle Ordovician regional fauna, is limited to a much smaller area, marginal to the Gondwana supercontinent; (3) the strong provincialism persistent in the late Middle Ordovician contributed to increased gamma biodiversity during the Great Ordovician Biodiversification Event. [ABSTRACT FROM AUTHOR]

Three trilobites, Hypagnostus aff. clipeus, Cotalagnostus sp. nov., and Pagetides johannis sp. nov., not previously recorded in Newfoundland, are associated with Onymagnostus cf. hybridus, H. mammillatus, Peronopsis cf. fallax minor, Paradoxides ( P.) davidis davidis, P. ( P.) cf. abenacus, Brunswickia ( B.) cf. jaculator, B. ( Jincella) sp., Agraulos sp., and some hyolithids, stenothecid molluscs and orthid, acrotretid and lingulate brachiopods in a thin limestone within dark grey, slaty mudstones of the Young's Cove Formation on St. John's Island, Fortune Bay. A stratigraphical position within the Cambrian punctuosus Zone in the upper part of the Drumian Stage is indicated. The presence of the oculate eodiscid Pagetides in late mid-Cambrian rocks, within the Avalon Tectonostratigraphical Zone, is highlighted, because the genus was previously only known associated with the much earlier Cambrian olenellid zones of Laurentia. Paradoxides ( P.) cf. abenacus and the species of Brunswickia ( B.) close to peregrina, respectively, provide a link with the New Brunswick mid-Cambrian and paradoxissimus successions in England and Scandinavia, whereas the specimens of Hypagnostus aff. clipeus indicate a more global significance in common with forms in the punctuosus sequences of Siberia and Australia. The St. John's Island sequence includes lithofacies and fossils typical of the Manuels River Formation preserved elsewhere in southeastern Newfoundland. This is the first recognition of such a sequence in the Young's Cove Formation of Fortune Bay on the western margin of the Avalon Tectonostratigraphical Zone. [ABSTRACT FROM AUTHOR]

Strata of the Campbellton Formation, nearly 1 km-thick and known for its diverse fossil assemblage of early plants, arthropods, and fish, can be divided into six facies associations: (1) restricted lacustrine, (2) marginal lacustrine, (3) near-shore lacustrine, (4) coastal-deltaic, (5) sandy to gravelly alluvial plain, and (6) gravelly proximal alluvial environments. Lacustrine deposits with restricted circulation, due to depth or stagnation, are fine-grained with preserved organic material. The marginal lacustrine association consists of massive siltstone and very fine sandstone, interbedded with conglomerate. The latter are interpreted to have shed from older volcanic units forming the basin walls. The near-shore lacustrine association is characterized by rippled sandstone with microbialites. Alluvial strata include interbedded imbricate to nonimbricate conglomerate, trough cross-stratified sandstone, and barren to plant-bearing siltstone. Rare exposures of thickly bedded imbricate to weakly imbricated cobble-boulder conglomerate with sandy plant-bearing lenses are interpreted as products of hyperconcentrated debris flows. In the western belt, a braided-fluvial system had paleocurrents flowing WNW. Coastal-deltaic deposits west of the fluvial outcrops, containing aquatic vertebrates and invertebrates, had paleocurrents flowing ESE, suggesting a confined body of fresh or brackish water. In lower parts of the eastern belt, lacustrine facies are prevalent, representing a large open lake. Alluvial facies dominate upper parts of the formation, representing an eastward-flowing axial braided river system, with proximal alluvium shed transversely from the basin margins. Although most strata have a volcanic provenance, only one outcrop in the lacustrine beds shows evidence of active volcanism during deposition of the Campbellton Formation. [ABSTRACT FROM AUTHOR]

The Horn Plateau Formation, composed of isolated reefs, is part of the Devonian strata that formed in the Mackenzie Basin in the Northwest Territories, Canada. The reefs stretch over a ∼350 m northeast-southwest trend and are dominated by tabulate and rugose corals in the northeast, near exposed Canadian Shield rocks, and stromatoporoids further out in the basin. Detailed facies analyses of each reef type shows distinct differences in their biological makeup, energy regimes, and carbonate sedimentation rates. Geochemical analyses (stable isotopes and rare-earth elements) set against established paleogeography in the Mackenzie Basin reveal that the coral-dominated and stromatoporoid-dominated reefs grew under different ecological conditions. Separations in the data imply that the coral-dominated reefs grew in waters that were relatively enriched in nutrients and the stromatoporoid-dominated reefs, further down the ramp, were in oligotrophic conditions. With no current established method to directly measure Paleozoic nutrient levels or to detect where they were sourced from, it is unclear why the coral-dominated reefs experienced higher nutrient levels. The paleogeography of the Mackenzie Basin could have affected the apparent stratification of nutrients on the carbonate ramp. Possible nutrient sources in the area are from coastal upwelling from the open ocean northwest of the ramp, or locally sourced nutrients from runoff on the adjacent exposed Canadian Shield rocks. [ABSTRACT FROM AUTHOR]

Holorhynchus giganteus Kiaer, 1902, a common Late Ordovician (mid-Ashgill) pentameride brachiopod in the Baltic region, Kazakhstan, and southern Tien Sham is documented for the first time from the Badanjilin Formation (mid-Ashgill) of western Inner Mongolia (Alxa block), North China. Serial sections of the Chinese material confirm the presence of a vestigial ventral median septum in the early growth stage of H. giganteus, but the septum becomes embedded in the secondary shell thickening at the adult growth stage. A survey of the type material from Norway and additional material from other regions indicates that the incipient ventral median septum is a much more commonly developed structure than was previously believed. The presence of a well-developed pseudodeltidium in the Tien Shan material of H. giganteus and the absence of such a structure in conspecific material from many other regions require a systematic revision of the generic group. Holorhynchus has rodlike crura (=brachial processes) that do not form flanges at their junctions with the inner hinge plates (=outer plates = crural plates) and outer hinge plates (inner plates). This, together with the development of a crude spondylial comb structure, points to its affinity to the Virgianidae rather than to the Stricklandiidae. Holorhynchus can be regarded as a Lazarus taxon because of its absence during the crisis (Hirnantian) and survival (early-middle Rhuddanian) intervals associated with the Late Ordovician mass extinction and its reappearance in Kazakhstan and North China during the Early Silurian (late Rhuddanian-early Aeronian). The mid-Ashgill Holorhynchus fauna, typified by a number of large-shelled pentamerides, was common in the Baltic region, the Urals, Kazakhstan, Tien Shan, Alxa, Qaidam, Kolyma, and east-central Alaska, but largely absent from Laurentia and Siberia (except for Taimyr) in the ancient tropical-subtropical regions. This paleobiogeographic pattern agrees with the general pattern of the Late Ordovician brachiopod provincialism. [ABSTRACT FROM AUTHOR]

The Upper Ordovician (mid-Ashgill) Xiazhen and Changwu formations in the Zhejiang-Jiangxi border region of southeastern China contain an abundant and diverse suite of brachiopods. A cluster analysis of 59 key samples from 180 collections (over 23 000 specimens) allowed delineation of eight distinct brachiopod communities, herein named the Ectenoglossa minor Community, the Eospirifer praecursor Community, the Ovalospira dichotoma Community, the Antizygospira liquanensis – Sowerbyella sinensis Community, the Kassinella shiyangensis Community, the Altaethyrella zhejiangensis Community, the Tcherskidium jiangshanensis Community and the Foliomena folium Community. These communities occur predominantly in limey, clayey, to silty mudstone facies, similar to Ziegler's Early Silurian brachiopod communities in the Welsh Borderland. On the basis of lithological, faunal, and paleogeographical evidence, the eight communities are interpreted to have distributed along an onshore–offshore gradient from BA1 to BA6 settings on the northeastern margin of the Zhe-Gan Platform. In a broad paleo-embayment and mixed carbonate–siliciclastic shelf setting, the distribution of the eight brachiopod communities appears to have been controlled primarily by water depth because a given brachiopod community can be found in different lithofacies. Substrate types, however, must have played an important role, as some of the communities show preferred lithofacies. This study shows that the ecological zonation and community organization of the Late Ordovician pre-extinction brachiopods were similar to those of Early Silurian post-extinction brachiopods, although pronounced brachiopod provincialism during the Ashgill makes it difficult to directly correlate these communities with coeval brachiopod communities reported from other paleo-plates.Les formations de Xiachen et de Changwu de l'Ordovicien tardif (Ashgillien moyen) dans la région de la frontière Zhejiang-Jiangxi du Sud-Est de la Chine contiennent une suite abondante et diversifiée de brachiopodes. Une analyse typologique de 59 échantillons clefs provenant de 180 collections (plus de 23 000 spécimens) a permis de délimiter huit communautés distinctives de brachiopodes nommées ici la communauté Ectenoglossa minor, la communauté Eospirifer praecursor, la communauté Ovalospira dichotoma, la communauté Antizygospira liquanensis–Sowerbyella sinensis, la communauté Kassinella shiyangensis, la communauté Altaethyrella zhejiangensis, la communauté Tcherskidium jiangshanensis et la communauté Foliomena folium. Ces communautés se retrouvent surtout dans des faciès de mudstone à chaux, d'argileux à silteux, semblable aux communautés de brachiopodes de Ziegler du Silurien précoce dans la Bordure Galloise (Angleterre). Selon les évidences lithologiques, fauniques et paléogéographiques, les huit communautés se seraient distribuées le long d'un gradient côtier et extracôtier dans des environnements BA1 à BA6 sur la bordure nord-est de la plate-forme de Zhe-Gan. Dans un environnement de grande paléobaie ouverte et de plate-forme à mélange de carbonates et de siliclastiques, la distribution des huit communautés de brachiopodes semble avoir été contrôlée surtout par la profondeur de l'eau puisqu'une communauté donnée de brachiopodes peut se retrouver dans différents lithofaciès. Les types de substrats ont cependant dû avoir joué un rôle important puisque quelques communautés présentent des lithofaciès préférentiels. La présente étude montre que la zonation écologique et l'organisation des communautés des brachiopodes avant extinction à l'Ordovicien tardif étaient semblables à celles des brachiopodes post-extinction du Silurien précoce, bien que le provincialisme prononcé des brachiopodes au cours de l'Ashgillien rende difficile la corrélation directe entre ces communautés et les communautés contemporaines de brachiopodes provenant d'autres paléoplaques.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

The latest Katian (Late Ordovician) is marked by the third biodiversity climax of the Great Ordovician Biodiversification Event (GOBE) prior to the Late Ordovician mass extinction (LOME). In this study, the Chemical Index of Alteration (CIA) is used to determine the paleoenvironmental change recorded in the Arisu Member, the Siltstone Member, and the Sandstone Member of the Terekawat (= Tierekeawati) Formation (upper Katian) in the Tarim Basin, northwestern China. CIA values from these members are plotted in A–CN–K ternary diagrams respectively. Linear regression and 95% confidence interval estimation results indicate that these deposits were derived from the same parent rock, and the corrected CIA (CIA corr.) values reveal significant paleo-climate changes during Late Ordovician. Sea-surface temperatures (SSTs) have been estimated by comparing 31 modern estuary systems. These data show that the CIA corr. values dropped from 77.41 to 64.83, corresponding to an interpreted temperature drop from 20.5 to 10.2 °C in the Dicellograptus complexus graptolite Biozone of the upper Katian (Ka-4). CIA corr. values varied within a range of 67.63–70.16, implying temperature fluctuations between 12.5 and 14.6 °C in the lower to middle Paraorthograptus pacificus Biozone. CIA corr. values rose again from 69.09 to 76.05, corresponding to a temperature rise from 13.7 to 19.4 °C in the upper Paraorthograptus pacificus graptolite Biozone of the latest Katian. This is interpreted to be a cooling and warming cycle, corresponding to the mid-Boda cooling and the late-Boda warming events. This study suggests that the climate change during late Katian was more intense than previous thought, especially in subtropical zones of Paleo-Tethys. This cooling event enhanced the thermohaline ocean circulation and became one of the major factors causing the well-known late Katian faunal dispersal (i.e. the Boda event). Hirnantian glaciation would have further promoted global oceanic cooling, over-stressed the ecosystems, and triggered the LOME. • Chemical Index of Alteration and confidence interval estimation are used to reconstruct climate change. • A temperature drop from 20.5 to 10.2°C and a subsequent rise are estimated in the Tarim Basin during the Late Ordovician. • This cooling event enhanced the thermohaline ocean circulation and contributed to the faunal dispersal (i.e. Boda event). • Hirnantian glaciation event doubled the cooling effect on ecosystem compared with this cycle. [ABSTRACT FROM AUTHOR]

Iron‐rich nodules occur on the Yangtze Platform, South China, especially along the marginal area, during the late Middle and early Late Ordovician (Darriwilian–Sandbian). Based on the study of samples from the Daling section, Anhui Province, these nodules include: (1) oncoids; (2) coated bioclasts; and (3) coated micritic intraclasts, all of which potentially have a similar biological origin. The nodule‐bearing strata were deposited in a midouter ramp setting, indicating sediment starvation and open marine conditions, possibly combined with anoxia in deeper basinal areas and cool water upwelling during the formation of the nodules, rather than terrestrial input or local tectonic movement. The widespread distribution of iron‐rich nodules at this time was probably favoured by high sea level and cooling climate, conditions that simultaneously favoured the evolutionary radiations of the GOBE in South China. Thus, these nodules form a time‐specific signature of a critical time in the evolution of the marine ecosystem in the context of local environmental background along the marginal Yangtze Platform. [ABSTRACT FROM AUTHOR]

The Late Ordovician marks an epoch of substantial change during Earth’s geologic history. It documents the first mass extinction event of the Phanerozoic, which wiped out a plethora of marine genera. Though signatures of the extinction event are quite evident on the species level, there are many underlying uncertainties as to which factors drove the near destruction of Ordovician marine life. The exact causes and contributing factors of the Late Ordovician Mass Extinction (LOME) are highly debated. Previous studies propose processes such as redox shifts, volcanism, deep-water anoxia, low atmospheric oxygen, or excess CO2 as significant influencers. In this study, we utilized a multi-archive/proxy approach in reconstructing paleoenvironmental, stratigraphic, chronologic, and diagenetic signatures of halite and carbonate sequences from two localities containing the Ordovician–Silurian boundary. Our preliminary findings suggest that an abrupt, multi-pulsed glaciation was probably the main driver of the LOME. However, the exact duration, intensity, and number of cooling pulses are still up to interpretation and will require additional geochemical work to paint the entire picture. Samples were obtained from two localities of similar low paleo-latitudes. Marine halite and carbonate were obtained from the upper Ordovician Red Head Rapids Formation, Hudson Bay Basin, Canada. Another suite of halite was collected from the Ordovician/Silurian Mallowa Salt Formation, Canning Basin, Western Australia. The diagenetic integrity of Red Head Rapids halite and carbonate were assessed through strontium isotope analysis. Since the strontium isotope remains in equilibrium with seawater, we can cross-analyse the preservation potentials of both marine archives. All sample results lay within the ± 0.00006 ‰ natural variation of 87Sr/86Sr measured in modern marine counterparts, providing evidence of primary material and accurate paleo-interpretations. Trace element chemistry study was conducted on halite samples from both localities. Previous studies suggested that the spikes of Hg, Mo, and U concentrations signify the aftermath of a greenhouse event that triggered the expansion of deep-water anoxia. Furthermore, heightened volcanic activity led to significant greenhouse gas emissions and produced a period of warming. Instead, our halite Hg, Mo and U concentrations are extremely low, many below detection limits, which correspond to glacial signatures of an icehouse. Interpretation of the sedimentary cerium anomaly of the Red Head Rapids and Mallowa salts also revealed characteristics of an oxygenated marine environment, with all calculated values below the threshold, typical of anoxia. Rigorous halite fluid inclusion analysis was conducted to qualitatively distinguish between primary and secondary material based on size, shape, orientation, and multiple growth pat­terns. Microthermometry homogenization temperatures derived quantitative distinctions between primary and secondary fluid inclusions of preserved and altered material, respectively. Paleotemperatures of primary fluid inclusions exhibited oscillations that were evident of daily/seasonal variation of inter- and/or glacial times, averaging approximately 24.2°C ± 0.5°C for the latest-Ordovician–earliest-Silurian. Apart from minor fluctuations, we noticed up to four major cool­ing pulses associated with the major glaciation characterizing the latest-Ordovician–earliest-Silurian time. [ABSTRACT FROM AUTHOR]

The conodont biostratigraphy for the Upper Ordovician - Upper Silurian carbonate shelf (Irene Bay and Allen Bay formations) and interfingering basinal (Cape Phillips Formation) facies is established for parts of Devon and Ellesmere islands, central Canadian Arctic Islands. Revisions to the interpreted regional stratigraphic relationships and correlations are based on the stratigraphic distribution of the 51 conodont species representing 32 genera, identified from over 5000 well-preserved conodonts recovered from 101 productive samples in nine stratigraphic sections. The six zones recognized are, in ascending order, Amorphognathus ordovicicus Local-Range Zone, Aspelundia fluegeli Interval Zone, Pterospathodus celloni Local-Range Zone, Pt. pennatus procerus Local-Range Zone, Kockelella patula Local-Range Zone, and K. variabilis variabilis - Ozarkodina confluens Concurrent-Range Zone. These provided a more precise dating of the members and formations and, in particular, the range of hiatuses within this stratigraphic succession. The pattern of regional stratigraphy, facies changes, and hiatuses is interpreted as primarily related to the effects of glacioeustasy associated with the terminal Ordovician glaciation and smaller Early Silurian glacial phases, the backstepping of the Silurian shelf margin, and the geodynamic effects of the collision with Laurentia by Baltica to the east and Pearya to the north. Conodont colour alteration index values (CAI 1-6.5) from the nine sections complement earlier graptolite reflectance data in providing regional thermal maturation data of value in hydrocarbon exploration assessments. [ABSTRACT FROM AUTHOR]

The lithostratigraphic term 'Eramosa' was introduced in Ontario more than a century ago to include a distinctive package of thin- to medium-bedded, black to medium-brown dolostones that make up key cuesta faces and railway roadcuts along the Eramosa River in the City of Guelph, southwestern Ontario, Canada. This stratigraphic unit makes up part of a stacked carbonate succession that constitutes one of the most economically significant Paleozoic sedimentary rocks in Ontario. The strata assigned to the Eramosa have a complex history of lithostratigraphic study, and the relative age, regional lithostratigraphic relationships, and varied depositional environments of the Eramosa were poorly understood. This research, which combines conodont biostratigraphy and carbonate carbon (δ13Ccarb) isotope stratigraphy to generate a detailed chronostratigraphic framework for the Eramosa Formation in southwestern Ontario, is part of a regional-scale surface and subsurface mapping initiative of the Silurian strata by the Ontario Geological Survey. Dolostone samples from Wiarton and the City of Guelph, Ontario, yielded three biostratigraphically important conodonts: Ozarkodina sagitta rhenana, Kockelella walliseri, and Kockelella ortus ortus. The carbonate carbon (δ13Ccarb) isotope data from the studied intervals record the descending limb of the Sheinwoodian (Ireviken) positive δ13Ccarb isotope excursion, including a distinctive positive shift in δ13Ccarb isotope values typical of records of the descending limb of the excursion in Laurentia and Baltica. Aldridgeodus minimus was also recovered from these conodont faunas and co-occurs with Kockelella walliseri, below the last occurrence of Ozarkodina sagitta rhenana (Lower Kockelella walliseri Zone), suggesting that the range of Aldridgeodus minimus should be extended lower into the Sheinwoodian Stage. [ABSTRACT FROM AUTHOR]

In situ rare-earth element (REE) compositions have been measured in early vertebrate microremains from the Lower Devonian basin of Andrée Land (Svalbard), with the aim of obtaining information about their early depositional environment and potential reworking. Vertebrate microremains with different histology were used for the analyses, sourced from two different localities of marginal marine to freshwater sediments from geographically distant parts of the Grey Hœk Formation (Skamdalen and Tavlefjellet members). We selected thelodont and undescribed ?chondrichthyan scales, which allowed us to define potential taxonomic, histological, and taphonomic variables of the REE uptake. Results showed REE concentrations to be relatively uniform within the scales of each taxon, but apparent discrepancies were visible between the studied localities and separate taxa. The compilation of REE abundance patterns as well as REE ratios have revealed that thelodont and ?chondrichthyan originating from the same locality must have had different burial and early diagenetic histories. The shapes of the REE profiles, together with the presence and absence of the Eu and Ce anomalies, equally suggested different depositional and diagenetic environments for these two sympatric taxa resulting from either stratigraphical or long-distance reworking. The REE concentrations appear to have visible differences between separate dental tissues, particularly between enameloid and dentine of thelodonts, emphasizing the importance of in situ measurements in microfossil biomineral geochemistry. [ABSTRACT FROM AUTHOR]

The 'butter shale' Lagerstätten of the Cincinnati Arch have produced an abundance of articulated trilobites, along with assorted bivalves and cephalopods. These bluish gray shales are rich in clay, poorly calcified, and show vague internal bedding in outcrop. Butter shales form a repetitive motif with similar lithological and paleontological characteristics, suggesting conditions existed that can be explained by the interference between different orders of sequence stratigraphic cyclicity. The characteristics that define butter shales include rarity of coarser interbeds, homogenous, fine grain size, and abundance of burial horizons. The overriding control is siliciclastic sediment supply. During third-order transgressions, sediment supply to the basin is too low to produce thick shale-prone intervals. Conversely, during third-order falling stages, sediment supply is generally too high to favor butter shale deposition. Butter shales formed preferentially during a third-order highstand systems tract, and two subtly different variants resulted from the superimposed effects of higher order cycles. Highstands moderated by small-scale transgressions are characterized by lower background sedimentation and fewer, thinner mud deposition events. Superposition of small-scale sea-level fall on highstands produced increased background sedimentation, higher silt, and patchy fossil occurrences. Juxtaposition of various scaled highstand systems tracts provided the optimal butter shale conditions, characterized by elevated mud influx and frequent episodic burial events, leading to abundant, articulated trilobites and associated fauna. In these scenarios, episodic events provide sufficient mud to smother local faunas and create a soft, fine-grained substrate that prohibited recolonization by taxa adapted to firm substrates. Each scenario differs from the others with respect to sedimentology and faunal composition. [ABSTRACT FROM AUTHOR]

A recovery brachiopod fauna occurs in the lower Niuchang Formation (upper Rhuddanian - lower Aeronian, Llandovery) of the Xinglongchang section, Meitan County, northern Guizhou Province, South China. Nine collections were made at the section, all of which are dominated by brachiopods, and three associations are recognized here and their paleoecology is discussed. Paleoenvironmental analysis shows a shallowing upward trend for the lower Niuchang Formation, although a global transgression was happening at that time. The balance between the global transgression and the regional Qianzhong Uplift guaranteed a stable environment for the formation of the Niuchang Formation and the recovery of brachiopods in South China after the end-Ordovician mass extinction. In addition to the traditional methods of principal component analysis and cluster analysis, a relatively new technique to paleontology, 'network analysis', is applied successfully in this study. It is suggested that network analysis could be used as one of the supporting methods in investigating brachiopod paleoecology. [ABSTRACT FROM AUTHOR]

The Kuanyinchiao Formation (Hirnantian, Upper Ordovician), yielding the typical Hirnantia fauna, has commonly been accepted as representing cool-water sediments deposited during the glacial interval in the Hirnantian Global Boundary Stratotype Section and Point (GSSP) region of South China. Recent investigation reveals that the uppermost carbonate-dominated part of this formation yields a warm-water rugose coral fauna with Silurian affinities at many localities of northern Guizhou Province, which substantially differs from the underlying cool-water fauna. This suggests that these carbonates were probably postglacial warm-water sediments, rather than having formed during the Hirnantian glacial interval as previously thought. Such a conclusion is consistent with the evidence from the associated brachiopod fauna, i.e., the Dalmanella testudinaria - Dorytreta longicrura community, which is similarly distinct from the underlying typical Hirnantia fauna. The sedimentological data show warm-water features at the same level (e.g., the presence of oolitic grains), also supporting this new interpretation. [ABSTRACT FROM AUTHOR]

The distribution pattern of early Telychian ( turriculatus-crispus graptolite biozone) red beds in the Eastern Yangtze Platform of South China is reconstructed based on regional geologic data. The red beds are developed in three areas, which are separated by regions without red deposition. The distribution pattern indicates that the Cathaysian Oldland was the provenance of sediment rich in ferric oxides, which are essential for the formation of red beds. Silurian marine siliciclastic red beds, both in China and worldwide, tended to develop during times of relatively low sea level. Coeval hematitic oolites that formed far from the coast may record a change from reducing to oxidizing conditions in the ocean. Furthermore, it is likely that a fall in global sea level, a transition from reducing to oxidizing conditions in the ocean, and a cooling climate, all of which were closely related to the early Telychian Valgu Event, promoted the global development of marine red beds during this period. [ABSTRACT FROM AUTHOR]

Previous studies of conodonts suggested that the upper member of the Xiushan Formation (late Llandovery) corresponds to the Pterospathodus eopennatus Superbiozone, but no data were obtained from the lower member in the Xiushan area. In this study, the entire Xiushan Formation was resampled from the Datianba section in the Xiushan area of Chongqing City on the Yangtze Platform in South China. In total, 40 samples were collected and processed. Fifteen of these samples contained identifiable conodont specimens. The present study indicates that the lower member and main part of the upper member of the Xiushan Formation correspond to the Pterospathodus eopennatus Superbiozone, while the top of the upper member probably correlates with the Pterospathodus celloni Superbiozone. [ABSTRACT FROM AUTHOR]

The Moose River Basin in Ontario, Canada, contains nearly 1 km of Silurian marine strata, and although it has been studied for more than a century, its precise correlation globally has not been constrained. Herein, a core from the Victor Mine in the Moose River Basin was examined for conodont biostratigraphy and carbonate carbon (δ13Ccarb) isotope chemostratigraphy to provide a detailed chronostratigraphic framework for the Silurian strata (Severn River, Ekwan River, and Attawapiskat formations) in the Moose River Basin. The recovery of Aspelundia expansa, Aspelundia fluegeli fluegeli, Distomodus staurognathoides, Ozarkodina polinclinata estonica, Pterospathodus eopennatus, and Aulacognathus bullatus, as well as the lower Aeronian, upper Aeronian, lower Telychian (Valgu), and ascending limb of the Sheinwoodian (Ireviken) positive carbonate carbon (δ13Ccarb) isotope excursions provide significantly improved chronostratigraphic correlation of Llandovery strata in the Moose River Basin. [ABSTRACT FROM AUTHOR]

Early Devonian graptolites are widely distributed within the 30°N and 30°S parallels of paleolatitude, with only a few known locations outside the 30° parallel. Only three early Devonian graptolite locations, i.e., west Yunnan, southeast Guangxi (in low paleolatitude), and south Xizang (Tibet) (in middle-high paleolatitude), have been reported in China. An Early Devonian graptolite fauna of moderate diversity, including three genera and 14 species, is described from the Qinzhou-Yulin region in southeast Guangxi, China, including Uncinatograptus jadae sp. nov. and Neomonograptus aequabilis latus subsp. nov. Based on these taxa, four biozones, the Uncinatograptus uniformis Biozone, the tentative Uncinatograptus praehercynicus Biozone, the tentative Neomonograptus falcarius Biozone, and the Uncinatograptus yukonensis Biozone, are erected in ascending order. The Lower Devonian graptolite biozonation in Guangxi agrees with the global standard. However, the graptolite biodiversity below the Uncinatograptus yukonensis Biozone in the Qinzhou-Yulin region is lower than those of the other parts of the world. In the present study, the tentatively recognized Neomonograptus falcarius Biozone has only the index species. In the study region, the species Uncinatograptus hercynicus (Perner) is absent. Thus, we tentatively employ the Uncinatograptus praehercynicus Biozone as a possible substitute for the Uncinatograptus hercynicus Biozone. [ABSTRACT FROM AUTHOR]

This study provides a taxonomic treatment and comparison of lower Gorstian (Silurian) radiolarians recovered from two sections of the Cape Phillips Formation in the Canadian Arctic that accumulated in two different paleoenvironmental settings. Twilight Creek is more basinal, located ∼100 km from the paleo-shelf margin, whereas Snowblind Creek is located within 1 km of the paleo-shelf break, on Cornwallis Island. The fauna, like other material from the Cape Phillips Formation, is extremely well preserved and was recovered from four samples at two localities, all from the Lobograptus progenitor graptolite Zone, an interval that has few published studies regarding radiolarians. A total of 28 species are recognized, of which two are new and described herein ( Fusalfanus bilateralis n. sp. and Pseudospongoprunum parvispina n. sp.), belonging to the Haplotaeniatidae, Inaniguttidae, 'Sponguridae', Ceratoikiscidae, Entactiniidae, Palaeoscenidiidae, and Secuicollactidae. Based on these new data, the stratigraphic ranges of some taxa are extended. The species concepts of several closely related inaniguttid species are re-evaluated. As a result, Inanihella tarangulica Nazarov and Ormiston, 1984 is transferred to the genus Fusalfanus Furutani, 1990 based on cortical shell structure, and Inanihella duroacus, Inanihella legiuncula, and Inanihella perarmata are synonymized under Fusalfanus tarangulica sensu lato. Aciferopylorum admirandum is transferred to Fusalfanus and considered a junior synonym of Fusalfanus osobudaniensis. The comparative analysis of taxonomic richness and composition reveals that the more distal sample from Bathurst Island exhibits a slight, but statistically significant, higher alpha diversity at the species rank than the more proximal basin/platform samples from Snowblind Creek. Biodiversity indices at the genus rank produced mixed results, indicating that differences between sites are at best slight. There is also a strong taxonomic separation between the fine and coarse size radiolarian fractions recovered during the sieving of each sample. The siliceous sponge spicule assemblages from these faunas show an inverse diversity relationship to the radiolarians in that Snowblind Creek contains greater alpha diversity than Twilight Creek. This study provides the first documentation of facies-controls in Silurian radiolarian diversity and is useful in evaluating the role of taxa used in biostratigraphy. [ABSTRACT FROM AUTHOR]

Nonglacial deposits of Middle Wisconsin age are being discovered with increased frequency across a broad region of southern Ontario, Canada, and provide strong evidence for a time of significant ice withdrawal from the lower Great Lakes region. With each new discovery, a refined understanding of regional climatic and paleoecological environments is emerging. In this paper, we present the results of a sedimentological and paleoecological study of a subtill organic deposit in Zorra Township, southwestern Ontario. The organic deposit, which lies beneath Nissouri Phase Catfish Creek Till (Late Wisconsin), has been dated by accelerator mass spectrometry at between 50.5 and 42.9 14C ka BP. The organic remains are contained within slack water pond deposits infilling a channel incised into till either of Early Wisconsin or Illinoian age. The fossil assemblage appears to be strongly influenced by taphonomic processes, including degradation due to oxidation, bacterial and fungal decay, and glacial overriding. Reworking and (or) recycling and selective sorting as well as long-distance transport has also influenced the composition of the fossil assemblage preserved. Nonetheless, meaningful paleoecological information is still obtained from this record. Collectively, the pollen and plant macrofossils indicate a boreal-type pine-spruce forest with temperatures cooler than present. The absence of arctic tundra plants, as are found in many other deposits of similar age in the lower Great Lakes basin, is notable. A pond or wetland inhabited by shoreline herbs, shrubs, and trees was present at or proximal to the site. The freshwater mollusc and ostracode assemblages are consistent with a shallow water habitat with dense submerged vegetation. The terrestrial mollusc assemblage suggests a taiga or transitional taiga-tundra fauna. Together, these fossil groups provide one of the most comprehensive environmental reconstructions of Middle Wisconsin time (oxygen isotope stage 3 or OIS3) in southern Ontario and serve to build on the ever-increasing database of paleoecological information accumulating for this episode of the late Quaternary. [ABSTRACT FROM AUTHOR]

An echinoderm association is reported from the ?early late Albian Paddy Member of the Peace River Formation of British Columbia, Canada. The association includes Frasericrinus mauricensis gen. et sp. nov., two additional distinctive crinoid column types, a poorly preserved asteroid, and an umbilical fragment of the cephalopod Stelckiceras. This is the first report of a Cretaceous isocrinid from North America. The echinoderm fossils are from the top of a succession of storm-deposited sandstones and mudstones (Boulder Creek Formation) that can be correlated southward into nearshore and terrestrial facies of the Paddy Member of the Peace River Formation. The echinoderm fossils were buried (and probably lived) about 12-14 km from the contemporaneous shoreline in an estimated water depth of 10-20 m. Integration of biostratigraphic and allostratigraphic schemes suggests that the echinoderms are of earliest late Albian age. The association of the echinoderm fauna with ammonites of Boreal affinity indicates deposition in northern waters, although the presence of Tethyan inoceramids in apparently coeval Paddy Member strata 270 km to the east suggests that northward-advancing water from the Gulf of Mexico had reached northwestern Alberta, if not actually merged with the Boreal embayment. The nearshore occurrence of Cretaceous stalked crinoids is indicative of an asynchronous, gradual migration of stalked crinoids to deep-water habitats, to which they are restricted in modern oceans. [ABSTRACT FROM AUTHOR]

Carbon isotopes are analyzed for the first time from the Ordovician-Silurian boundary interval in the Williston and Hudson Bay basins of Manitoba, revealing a prominent positive excursion. The nature of this excursion and its co-occurrence with the appearance of the Ozarkodina hassi Conodont Zone and a distinctive coral-dominated macrofauna indicate that this is the upper portion ( Metabolograptus persculptus Graptolite Zone) of the globally recognized Hirnantian isotopic carbon excursion (HICE). As a result, the Ordovician-Silurian boundary is placed at a higher position than previously thought, at the disconformable Stonewall - Fisher Branch formational boundary in the Williston Basin, and probably the Port Nelson - Severn River formational boundary in the Hudson Bay Basin. Disconformities within sections suggest periods of nondeposition due to subaerial exposure as sea level fluctuated during the Late Ordovician glaciation. Latest Ordovician (Hirnantian) deposition was far more widespread on the Laurentian craton than realized previously. Age determination and correlation having unprecedented precision are attainable within and between the Williston and Hudson Bay basins, and beyond. [ABSTRACT FROM AUTHOR]

Mayachernes maatiatus, a new genus and species of pseudoscorpion of the family Chernetidae (Arachnida: Pseudoscorpionida), is described from the Miocene Chiapas - Amber Lagerstätte, south of Mexico. This new fossil species represents an adult male specimen with hard-soft tissues preserved in great detail. It differs from all other living chernetids by a combination of diagnostic characters. Anatomical data were collected using high-resolution microscopy with regular to infrared-reflected light. Mayachernes maatiatus is the first newly described fossil species of pseudoscorpion from the Chiapas amber. This taxon also adds to knowledge of the Chernetidae diversity in the southernmost part of North America at the Neogene. [ABSTRACT FROM AUTHOR]

Microconchids have been described from the classic Pennsylvanian locality at Joggins, Nova Scotia. These encrusting tentaculitoid tubeworms have previously been mentioned and described from Joggins under the polychaete genus Spirorbis. Detailed morphological and microstructural investigation revealed that they belong to the species Microconchus carbonarius Murchison, confirming the previous tentative assignment (as Spirorbis carbonarius) made by Sir J. William Dawson in the nineteenth century. The occurrence of the same species in Upper Carboniferous deposits of England provides evidence supporting a connection between England and Nova Scotia in the Late Carboniferous (Pennsylvanian). Migration of the species could have been possible via brackish seas connecting both areas during maximum sea level during the Pennsylvanian. The species inhabited retrograding poorly drained coastal plain and open-water brackish environments, encrusting bivalve shells and plant remains in both sandstone and limestone deposits. Their high density (up to 19 individuals/cm2) may have resulted from their aggregative behaviour, high fecundity, and a lack of any competition with other skeleton-bearing encrusters. The large number (34%) of regenerated tubes indicates that microconchids were often preyed upon by associated animals, most probably fishes, which could graze on their dense encrusting aggregations. [ABSTRACT FROM AUTHOR]

Totolapa is one of the amber Lagerstätten from Chiapas, southwestern Mexico, which include the Simojovel and Huitiupán deposits. Despite the remarkable paleobiological heritage of Chiapas amber biota, the fossil record of ants from Totolapa has so far not been well studied. Based on exceptionally preserved specimens, four ant genera from the Totolapa amber deposits are reported in this paper, including Forelius, Azteca, Tapinoma, and Camponotus (Hymenoptera, Formicidae). Whereas the genera Azteca, Tapinoma, and Camponotus are previously known from amber quarries of Simojovel, this paper represents the first record of the presence of Forelius in Chiapas amber. [ABSTRACT FROM AUTHOR]

Ediacaran strata in the Conception and St. John's groups that are exposed in the Catalina Dome, eastern Newfoundland, comprise a succession that is thinner but otherwise broadly similar to that known from the well-studied outcrops near Mistaken Point in southern Avalon Peninsula and Spaniard's Bay in northern Avalon. In all of these areas, strata consist of turbidites deposited in deep-water basin-plain and slope environments, but important differences help to constrain interpretations of basin history and Ediacaran paleobiology of eastern Newfoundland. A turbidite paleocurrent shift from easterly to southerly is consistent with the existing two-phase tectonic model for basin evolution previously proposed for the Avalon Peninsula. In the Catalina Dome, however, this shift occurred stratigraphically higher than at Mistaken Point but lower than at Spaniards Bay in the Avalon Peninsula. Probable seismoturbidites are common in the lower part of the Catalina succession, suggesting particularly active tectonism. Except in the very lowest 20 m of the succession (Drook and lowermost Mistaken Point formations) in which ash is absent, volcanic ash beds are both more common and more volumetrically significant throughout the succession than farther to the south and east, which suggests that deposition occurred closer to the volcanic arc. Volcanic ash beds persist higher stratigraphically, occurring within the Fermeuse Formation, which here contains diverse rangeomorph fossils in contrast with the low-diversity assemblage of Ediacaran discs prevalent in the Fermeuse Formation of the Avalon Peninsula. This distribution strongly reaffirms the importance of taphonomy in controlling the composition of deep-water Ediacaran assemblages. [ABSTRACT FROM AUTHOR]

One of the most distinctive components of the Late Triassic warm-water biota are alatoform, reclining bivalves of the genus Wallowaconcha. Wallowaconcha raylenea was first described from shallow-water, fine-grained Upper Triassic carbonate rocks of the Wallowa terrane, northeastern Oregon, and later found in coeval limestone in the Yukon. Fossils of the family Wallowaconchidae are easily recognized and readily distinguished from other fossil groups by their large size (over a metre in length), alatoform morphology, and especially the chambered wing-like extensions likely associated with photosymbiosis. Several different taxa of Norian age inhabited lagoon and reef-related settings on four separate terranes of western North America (Antimonio terrane, Sonora, Mexico; Wallowa terrane, northeastern Oregon; Stikine terrane in the Yukon; Chulitna terrane of Alaska), which during Triassic time existed as volcanic islands in the eastern Panthalassa Ocean. Outside eastern Panthalassa in the eastern Tethys, two other species of Wallowaconcha come from distant localities in Asia and Arabia. We here report for the first time, in presumed Rhaetian limestone of the upper part of the Parson Bay Formation, Vancouver Island, newly discovered examples of Wallowaconcha. They are from Wrangellia and, based on size and shape of the chambers, are assignable to W. raylenea but unlike other examples they appear to be Rhaetian in age. This species of giant bivalve inhabited warm-water locales outboard of North America during the Late Triassic, and its presence provides possible paleobiogeographic links of Wrangellia with both Stikinia and the Wallowa terrane. [ABSTRACT FROM AUTHOR]

A single specimen of decapod crustacean, preserved in ventral view and compressed, represents a new genus and species of eryonid lobster, Wrangelleryon perates . The discovery in Lower Jurassic (Hettangian) sediments of the Sandilands Formation in British Columbia represents the first occurrence of Eryonidae in North America and reinforces a global distribution of the family in the Jurassic. The occurrence in British Columbia on the Wrangellia terrane supports the lower latitude setting in which the species lived. [ABSTRACT FROM AUTHOR]

Enigmatic millimetre-scale micro-concretions with pseudocrystal faces and dominated by green clay minerals occur in unfossiliferous siliciclastic mudstone of the Lower Ordovician (479.0-466.0 Ma) Tonggao Formation, South China. The fossil-free mudstone unit is associated with local biodiversity decline. The mineralogy and mineral chemistry of these concretions were unknown previously, and this study comprises a preliminary investigation. The concretions are dominated by Fe-rich phyllosilicate minerals including glauconite and clinochlore, with minor quartz and traces of magnetite. The textural relations between the micro-concretions and the surrounding matrix, and the preservation of original mudstone laminations within the concretions, point to an origin during early diagenesis. The mineralogy and chemistry of these concretions are consistent with an origin in a restricted, hypersaline, relatively deep-water environment, in accordance with stratigraphical and paleonotological data. These micro-concretions provide clues for a stressed environment with poor water circulation and anomalies of salinity and oxygen. [ABSTRACT FROM AUTHOR]

Palaeontological exploration of the Bonnet Plume Basin in northwestern Yukon Territory, Canada, has revealed a Late Paleocene to Early Eocene macrofloral assemblage from a channel fill deposit. The flora is typified by cosmopolitan taxa and dominated by deciduous angiosperms, with the notable presence of , , and . Floras with a similar composition are known from Late Cretaceous through Early Eocene deposits in Alaska and the Canadian Arctic Archipelago, where they have been interpreted as evidence for warm, equable temperatures. This collection represents the most diverse known Paleogene plant macrofossil assemblage from the Yukon Territory and helps to expand our knowledge of ancient high-latitude floras. [ABSTRACT FROM AUTHOR]

n. sp. is described from the upper part of the York River Formation (Gaspé Sandstones Group), lower Eifelian (brachiopod Zone), Rimouski County (Quebec, Canada). This new species is considered part of a new lineage of characterized by the presence of interstitial corallites. This study reveals for the first time that the granules on the lower (proximal) side are distributed irregularly, their density being higher in the central area of this side than at the periphery. The unusual association of the tabulate coral ( Pachyprocteria) with the 'worm' is pointed out. The record of the new species adds to the known paleogeographic distribution of Pachyprocteria in North America (Laurussia). [ABSTRACT FROM AUTHOR]

Ordovician graptolite faunal compositions between the Laurentia and Baltica margins of the Iapetus Ocean differ considerably in the upper Darriwilian (Da 3 - Da 4; upper Middle Ordovician). Detailed investigation of a number of sections in the Table Head and Goose Tickle groups in western Newfoundland and the Elnes Formation of Norway provides important new faunal data for the interval from the Biozone to the Biozone. The and biozones are introduced for the Table Head and Goose Tickle groups and can be recognized widely in North America. The characteristic, but poorly correlatable, shallow-water endemic faunas of the platform regions (Atlantic and Pacific faunal realms) grade into the cosmopolitan oceanic graptolite faunas (isograptid biofacies) and provide a means to precisely correlate cold-water and warm-water endemic graptolite faunas through transitional zones. The faunal differences between western Newfoundland and Scandinavia are less pronounced than hitherto assumed, and many faunal elements can now be recognized in both regions, allowing for a more precise biostratigraphic correlation. The paleobiogeographic differentiation of both regions has been based on few, but usually extremely common faunal elements, masking the presence of important biostratigraphic marker species. [ABSTRACT FROM AUTHOR]

During the middle Albian, a southward incursion of the Boreal Ocean flooded northern Alberta and adjacent British Columbia, forming a large embayment known as the Hulcross Sea. Marine mudstones of the Hulcross Formation and Harmon Member of the Peace River Formation record transgression, whereas sandstones of the Cadotte Member of the Peace River Formation record shoreline regression to the north. Abundant hummocky and swaley lamination in the Cadotte sandstone attest to the influence of storms on a shallow shelf. The Cadotte sandstone undergoes a lateral facies change from mud-free shoreface sandstone in the south to heterolithic offshore facies in the north. An articulated crinoid was found within a hummocky sandstone bed about 15 km seaward (north) of the shoreface-shelf facies transition. The articulated state of the crinoid indicates that it was buried very rapidly, and never exhumed. The arms through 20 mm of the column are preserved, but because the details of the aboral cup are not well preserved, this specimen must be left in open nomenclature. The elliptical columnals with a concave latus in the distal portion of the preserved column ally this specimen to the Bourgueticrinida, although with details of the aboral cup lacking and other characters atypical for Mesozoic bourgueticrinids, the Canadian specimen is placed in Bathycrinidae indeterminate. The oldest previously recorded bathycrinids were from the Upper Cretaceous (Maastrichtian), thus this report extends their range to the Lower Cretaceous (Albian). [ABSTRACT FROM AUTHOR]