Solitudinella hollardi n. gen., n. sp. (Brachiopoda, Lissatrypidae) dans le Praguien du Maroc pré-saharien

In the Ma'der (pre-Sahara of Morocco), the horizon of the marls and marly-limestones or the top of the Ihandar Formation (Pragian) has yielded numerous lissatrypid brachiopods. The study of their external and internal characters reveals differences from previously described lissatrypid genera and species and justifies the establishment of a new genus and a new species

<i>Dayia shirleyi</i> ALVAREZ & RACHEBOEUF, 1986, un brachiopode silurien dans les "Schistes de Mondrepuis" à Muno (sud de la Belgique)

At Muno, on the northern border of the Givonne Anticlinorium, numerous Dayia shirleyi ALVAREZ & RACHEBOEUF, 1986 occur in the lower part of the "Shales of Mondrepuis" overlying the "Conglomerate of Pepin", base of the Gedinnian. The presence of this brachiopod indicates that the lower part of the Lower Gedinnian at Muno is of Silurian (Prídolí) age

The last Frasnian Atrypida (Brachiopoda) in southern Belgium

The last representatives of the order Atrypida on the southern flank of the Dinant Synclinorium (Vaulx-Nismes area) in Belgium belong to Costatrypa, Spinatrypa, Spinatrypina (?Spinatrypina), Spinatrypina (Exatrypa), Iowatrypa, ?Waiotrypa, Desquamatia (Desquamatia) and Desquamatia (?Seratrypa). Among the thirteen described taxa, five are new: Spinatrypa tumuli sp. n., Iowatrypa circuitionis sp. n., ?Waiotrypa pluvia sp. n., Desquamatia (Desquamatia) quieta sp. n. and Desquamatia (?Seratrypa) derelicta sp. n. Supposed lissatrypid `Glassia drevermanni' Maillieux, 1936 from the late Frasnian Matagne shales is assigned to the Rhynchonellida. On the southern flank of the Dinant Synclinorium and in the Philippeville Massif, the Atrypida become extinct in the Palmatolepis rhenana Zone, significantly below the Frasnian-Famennian (F-F) boundary. Their extinction coincides with the first appearance of the green and black shales of the late Frasnian Matagne Formation, recording a transgressive-hypoxic event. Based on conodont data, this event takes place earlier on the southern flank of the Dinant Synclinorium than in the Philippeville Massif

Atrypidae (Brachiopoda) de la Formation de Fromelennes (fin du Givetien) et de la partie inférieure de la Formation de Nismes (début du Frasnien) aux bords sud et sud-est du Synclinorium de Dinant (Belgique)

The authors describe the Atrypidae from the lower and upper (Fort Hulobiet Member) members of the Fromelennes Formation and from the lower part (Pont d'Avignon and Sourd d'Ave Members) of the Nismes Formation. Four species are new: Desquamatia (Independatrypa) coenaubertorum n. sp., D. (Seratrypa) orbiculata n. sp., D. (S?) suppinguis n. sp. and D. (Neatrypa) gosseleti n. sp.; two are assigned to D. (Seratrypa) pectinata COPPER. P., 1967 and D. (Neatrypa) europaea STRUVE. W., 1964. Rare or poorly preserved specimens are provisionally designated as D. (Seratrypa) cf. pectinata, D. (S.) sp. R, D. (Neatrypa) sp.S and Spinatrypina sp. The specimens have been collected for the most part from five outcrops located at the southern and south-eastern borders of the Dinant Synclinorium. The succession of the atrypid zones at the base of the Nismes Formation in these different outcrops shows, from south to north-east, the diachronism which has been already pointed out formerly, of the base of the unit

Le genre Paraspirifer Wedekind, R., 1926 dans le Dévonien moyen de la partie orientale de l’Amerique du Nord

The authors describe seven species of the genus Paraspirifer WEDEKIND, R., 1926 on the basis of more than one hundred specimens from twenty-three localities in North America. Three of these species are new: P. conradi n. sp., P. halli n. sp. and P. clarkei n. sp. Two others are provisionally named P. cf. halli and P. sp. A. A Neotype is proposed for P. acuminatus (CONRAD, T.A., 1839) and the Lectotype of P. brownockeri (STEWART, G.A., 1927) is designated. The problems concerning the species Terebratula acuminatissima DE CASTELNAU, F., 1843 and Delthyris prora CONRAD, T.A., 1842 are briefly discussed. The genus Paraspirifer is confined to an area of ± 6.500.000 km2 in eastern North America. In New York, the biostratigraphic range-zone for the genus is from the upper Onondaga Limestone (Moorehouse Member) to the middle Marcellus Shale (Solsville Member) and, in Ohio and Ontario, from the upper part of the Columbus Limestone (Zones F — H) to the Silica Shale. In Indiana and Kentucky, the genus occurs in the upper Jeffersonville Limestone (P. acuminatus sensu lato Zone) and, in Illinois and Missouri, in the Grand Tower Limestone

Redescription des genres Septatrypa KOZLOWSKI, 1929 et Dubaria TERMIER, 1936 (Brachiopoda, Atrypida, Lissatrypidae)

The serial sections carried out on specimens of Septatrypa secreta KOZLOWSKI, 1929 and Dubaria lantenoisi TERMIER, 1936 show that the former of these species has a structure of the type "septalium" in the brachial valve. This "septalium" arises from the presence of an apical thickening which joins the median septum and the posterior and external part of the socket plates. This observation confirms the opinion of the authors who consider these two genera - of which the above species are the type species - to be distinct. The lectotype of Dubaria lantenoisi is designated. Some controversial genera of Septatrypinae are briefly discussed

Frasnian gypidulid Brachiopods from the Holy Cross Mountains (Poland), Comparative stratigraphic analysis with the Dinant Synclinorium (Belgium)

The authors describe the Frasnian gypidulid brachiopods from the Holy Cross Mountains (Poland) with special emphasis on their stratigraphic distribution. Among the five taxa distinguished, Physemella christinae is new, two are identified as Metabolipa cf. greindli (MAILLIEUX, 1909) and Neometabolipa duponti GODEFROID, 1974 and two others are provisionally named Novozemelia? sp. W and Neometabolipa ? sp. G. The Polish gypidulids reveal close affinities to those of the Dinant Synclinorium (Belgium) and the recognized successional replacement of characteristic genera and species in the latter area appears to be a supraregional pattern. A preliminary three-step sequence of gypidulid faunas (in ascending order: Novozemelia ?, Metabolipa and Neometabolipa) is outlined for the Frasnian of both regions. Its importance for correlations and age-inferences in conodont-poor, reef-related facies is clearly demonstrated by the examples from the Holy Cross Mountains

Exploring Biorthonormal Transformations of Pair-Correlation Functions in Atomic Structure Variational Calculations

Multiconfiguration expansions frequently target valence correlation and correlation between valence electrons and the outermost core electrons. Correlation within the core is often neglected. A large orbital basis is needed to saturate both the valence and core-valence correlation effects. This in turn leads to huge numbers of CSFs, many of which are unimportant. To avoid the problems inherent to the use of a single common orthonormal orbital basis for all correlation effects in the MCHF method, we propose to optimize independent MCHF pair-correlation functions (PCFs), bringing their own orthonormal one-electron basis. Each PCF is generated by allowing single- and double- excitations from a multireference (MR) function. This computational scheme has the advantage of using targeted and optimally localized orbital sets for each PCF. These pair-correlation functions are coupled together and with each component of the MR space through a low dimension generalized eigenvalue problem. Nonorthogonal orbital sets being involved, the interaction and overlap matrices are built using biorthonormal transformation of the coupled basis sets followed by a counter-transformation of the PCF expansions. Applied to the ground state of beryllium, the new method gives total energies that are lower than the ones from traditional CAS-MCHF calculations using large orbital active sets. It is fair to say that we now have the possibility to account for, in a balanced way, correlation deep down in the atomic core in variational calculations

Les Gypidulinae des niveaux recifaux du Frasnien de Frasnes et de Boussu-en-Fagne

The author revises the gypidulinids of the Frasnian reefs of Frasnes and Boussu-en-Fagne. He establishes Metabolipa n. gen., Neometabolipa n. gen. and Pbysemella n. gen. as well as the species Neometabolipa delhayei n. sp., N. duponti n. sp. and Pbysemella maillieuxi n. sp. He redescribes the species Pentamerus Greindli MAILLIEUX, E., 1909 and P. Broecki MAILLIEUX, E., 1909 respectively assigned to the genera Metabolipa and Neometabolipa. He recognizes in each reef a characteristic association of genera and species

Le genre Brachyspirifer Wedekind, R., 1926, dans le Siegenien, l’Emsien et le Couvinien du bord méridional du Synclinorium de Dinant

The author describes fourteen species and subspecies of the genusBrachyspirifer WEDEKIND, R., 1926 collected in the Siegenian, Emsianand Couvinian formations of the southern side of the Dinant synclinorium.Three species, B. minatus n. sp., B. mixtus n. sp. et B. niger n. sp. are new;five others are provisionally designed B. cf. crassicosta crassicosta,B. groupe crassicosta, B. cf. sphaeroides, B. cf. carinatus rhenanus and B.cf. ignoratus. A biostratigraphic zonation based on the vertical extensionof those species and subspecies is proposed and compared with that usedin the « Rhenische Schiefergebirge »