Isocrinid crinoids from the late Cenozoic of Jamaica

Eight species of isocrinines have been documented from the Lower Cretaceous to Pleistocene of Jamaica. New finds include a second specimen of a Miocene species from central north Jamaica, previously regarded as Diplocrinus sp. but reclassified as Teliocrmus? sp. herein. Extant Teliocrinus is limited to the Indian Ocean, although Miocene specimens have been recorded from Japan, indicating a wider distribution during the Neogene. One locality in the early Pleistocene Manchioncal Formation of eastern Jamaica has yielded three species of isocrinine, Cenocrinus asterius (Linné), Diplocrinus maclearanus (Thomson) and Neocrinus decorus Thomson. These occur in association with the bourgueticrinine Democrinus sp. or Monachocrinus sp. These taxa are all extant and suggest a minimum depositional depth for the Manchioneal Formation at this locality of about 180 m. This early Pleistocene fauna represents the most diverse assemblage of fossil crinoids documented from the Antillean region. RÉSUMÉ Huit espèces d'isocrinines de la période du Cretacé infeérieur au Pleéstocene de la Jamatque ont été documentés. Les nouvelles découvertes comprennent un deuxième spécimen d'unc espèce du Miocène du nord central de la Jamaique, auparevant considered comme l'espèce Diplocrinus, mais reclassified en tant que Teliocrinus? aux présentes. Le Teliocrinus existant est limité à l'océan Indien, même si on a relevé des spécimens du Miocene au Japon, ce qui est reVilateur d'une distribution plus répandue au cours du Néogène. Un emplacement de la formation de Manchioneal du Pleéstocene inférieur dans L'est de la Jamalque a livré trois espèces d'isocrinines : le Cenocrinus asterius (Linné), le Diplocrinus maclearanus (Thomson) et le Neocrinus decorus (Thomson). Ceux-ci sont présents en association avec les bourgueticrinines Democrinus ou Monachocrinus. Ces taxons sont tous existants et ils permettent de supposer que la formation de Manchioneal aurait une profondeur minimale de sedimentation d'environ 180 m à cet endroit. Cette faunc du Pleéstocene inférieur représente l'assemblage le plus diversifé de crinoides fossiles documentés dans la région des Antilles. [Traduit par la rédaction

A camerate crinoid from the Upper Silurian (Ludlow) Moydart Formation of Nova Scotia, Canada

Well-preserved fossil echinodcrms are uncommon in the Arisaig Group (early Silurian to early Devonian) of Nova Scotia. Although not preserving sufficient detail to enable specific identification, a crinoid, monobathrid camerate gen. et sp. indet. from the Moydart Formation (late Silurian, late Ludlow), shows the following features: a long, heteromorphic (N212) column of circular section and with convex nodals; a broad, conical dorsal cup with broad, high radials; fixed, uniserial arms which branch twice; 20 long, free arms that are uniserial most proximally, but are otherwise biserial; and numerous, elongate, blade-like pinnules. The column of this species differentiates it from a second taxon commonly preserved perpendicular to bedding in the Moydart Formation. Thus, while one species in this formation is preserved autochthonously in life position, another forms a crinoid lagersiatte and coquinas of more complete specimens, but is, at best, parautochthonous. RÉSUMÉ Les échinodermes fossiles bien conservés sont rares dans le Groupe d'Arisaig (Silurien inférieur au Dévonien inférieur) de la Nouvelle-Écosse. Bien qu'il n'ait pas conservé suffisamment de details pour permettre une identification précise, un erinolde à chambres monobathride de genre et espèce inditérminés provenant de la Formation Moydart (Silurien supérieur, Ludlow supérieur) présente ces caractéristiques : longue colonne hétéromorphe (N212) d'une section circulaire avec nodales convexes; vaste calice dorsal conique avec rayons endosquelertiques élevés et étendus, et bras unisériés à deux niveaux de ramifications; 20 longs bras libres qui sont unisériés proximalcment, mais qui sont bisériés plus loin; ainsi que maintes pinnules oblongues en fer de lance. La colonne de cette espèce la différencie d'un deuxième taxon ordinairement conservé perpendiculairement au litage dans la Formation Moydart. Ainsi, même si une espèce de cette formation est conservée de fa÷on autochtone dans une position vitale, une autre peut être formée de lagersiatte crinoides et de coquillages cunéiformes de specimens plus complets, mais, au mieux, subautochtones. [Traduit par la rédaction

The camerate crinoid Scyphocrinites Zenker in the Upper Silurian or Lower Devonian of New Brunswick, Canada

The mid-Paleozoic Scyphocrinites Zenker has a distal attachment modified into a globular flotation structure and, uniquely for a crinoid, joined the obligate plankton. Such a flotation structure has been found in the Indian Point Formation (Pridolian to Lochkovian) of Flatlands, northern New Brunswick. It is most likely Pridolian (Upper Silurian) based on the primitive morphology. This identification is confirmed by the globular gross morphology, multi-plated calcite structure, age and similarity to coeval fossils from Cornwall, southwestern England

Ichnology of the Palaeogene Richmond Formation of eastern Jamaica - the final chapter?

Previously unrecorded ichnotaxa from the Palaeogene Richmond Formation of eastern Jamaica, namely Cos-morhaphe cf. gracilis, Helminthoida crassa, Paleodictyon? isp. and Taenidium cameronensis, are described. The ichnotaxa are assigned to a previously defined deep-water Scolicia ichnocoenosis characteristic of turbidilic strata. The general exclusion of graphoglyptids in these strata is believed to reflect a combination of the relatively shallow-water depths in which the turbidilic strata accumulated, the abundant organic matter available for biological consumption, and the existence of fluctuating dysaerobic/anoxic and oxygenated conditions at, or immediately below, the sediment-water interface. RÉSUMÉ Les ichnofossiles auparavant non enregistrés provenant de la Formation paleogène de Richmond de Test de la Jamaique, soil Cosmorhaphe cf. gracilis, Helminthoida crassa, Paleodictyon? isp. et Taenidium cameronensis, sont décrits. Ces ichnofossiles sont assigned à l’assemblage d'eau profonde Scolicia anterieurement défini, caractérislique des strates de turbidites. L'absence générate de graphoglyplides dans ces couches est considérée comme refletant une combinaison de la faible profondeur relative à laquelle les strates de turbidites se sont accumulées, l'abondance de matière organique disponible pour la consommation biologique et l’existence de conditions anoxiques et oxygénées fluctuantes è l'interface eau-sédiment ou immédiatement en-dessous. [Traduit par la rédaction

On Oanducystis (col.) Stukalina (Crinoidea) from the Craighead Limestone Formation, Girvan district, Ayrshire

Only two nominal species of crinoid, the diplobathrid camerates Diabolocrinus craigheadensis Ramsbottom and Diabolocrinus globularis (Nicholson & Etheridge), have been described from the Ordovician (Chatfieldian; Sandbian) Craighead Limestone Formation, Craighead quarry, near Girvan, Ayrshire. In contrast, columnal morphotaxa are represented by over 20 taxa including those in open nomenclature. Two thecae from Craighead quarry and referred to Diabolocrinus sp. or spp. preserve features of the stem facet that are similar to specimens referred to Oanducystis (col.) spp. from the same locality. These columnal morphotaxa are synonymised with Diabolocrinus and left in open nomenclature. However, Diabolocrinus is limited to Laurentia, whereas the remaining morphospecies of Oanducystis (col.) Stukalina are limited to Kazakhstan and Estonia

Fossil assemblages and biostratigraphy of metamorphic rocks of the Nevado-Filábride Complex from the Águilas tectonic arc (SE Spain)

Abundant marine macrofossils are present in graphitic marbles and calc-silicate schists belonging to the Veleta nappe of the Nevado-Filábrides Complex (Internal Zones o the Betic Cordillera, SE Spain), in whet is called the Águilas tectonic arc. These fossil assemblages are dominated by crinoids, followed by minir cephalopods, brachipods, rugose corals, and putative sections of trilobites. In addition to these confidently identified groups, there are other sossil represented, but deformation and extensive recrystallization have destroyed anatomical characterers, hampering their taxonomic identification. Among the crinoids, the columnal parataxa Pentagonopentagonalis (col.) and Bystrowicrinus (col.) have been recognized. Planispiral cephalopods, assigned to either primitive ammonoids attributable to the order Agoniatitid (one of them being a possible member of the family Mimosphinatidae, or coiled nautilids, as well as orthoconid sections of possible orthoceratids of bactritids are present. Finally, there are rugose corals attributable to the family Phillipsastreidae, possibly Peeckiell. Among the remains with obscure taxonomic assignment, we recognize possible laminar calcareous algae and benthic foraminifers. Tinally, irregular, massive structures showing a rough laminar organization and longitudinal tubes with rounded sectiona are found in some black marble beds. These can be identified either as possible chaetetids or bryozoans. The report of these taxa has limited the rocks studied to the Emsian, late Early Devonian

Episkeletozoans and bioerosional ichnotaxa on isolated bones of Late Cretaceous mosasaurs and cheloniid turtles from the Maastricht area, the Netherlands

Isolated bones of three taxa of marine reptiles (Mosasaurus hoffmannii Mantell, Plioplatecarpus marshi Dollo and Allopleuron hofmanni (Gray)) from various levels within the Maastricht Formation (upper Maastrichtian) at the former ENCI-HeidelbergCement Group quarry (Maastricht, the Netherlands) exhibit bioerosional traces and encrustation. Episkeletozoans include dimyid, ostreid and monopleurid bivalves, at least three species of cheilostome and cyclostome bryozoans and two adnate calcareous foraminifera. The bones show biting traces (Gnathichnus pentax Bromley, Linichnus cf. serratus Jacobsen & Bromley and Machichnus isp.), as well as borings. The latter may be referred to Karethraichnus lakkos Zonneveld, Bartels, Gunnell & McHugh, which is here considered to be a junior synonym of Gastrochaenolites isp

Instrumentation for Millimeter-wave Magnetoelectrodynamic Investigations of Low-Dimensional Conductors and Superconductors

We describe instrumentation for conducting high sensitivity millimeter-wave cavity perturbation measurements over a broad frequency range (40-200 GHz) and in the presence of strong magnetic fields (up to 33 tesla). A Millimeter-wave Vector Network Analyzer (MVNA) acts as a continuously tunable microwave source and phase sensitive detector (8-350 GHz), enabling simultaneous measurements of the complex cavity parameters (resonance frequency and Q-value) at a rapid repetition rate (approx. 10 kHz). We discuss the principal of operation of the MVNA and the construction of a probe for coupling the MVNA to various cylindrical resonator configurations which can easily be inserted into a high field magnet cryostat. We also present several experimental results which demonstrate the potential of the instrument for studies of low-dimensional conducting systems.Comment: 20 pages including fig