Language: One English and one French contribution, both with trilingual abstracts in English, French, and German
This volume contains two papers:
Revision of upper Toarcian ammonites (Lytoceratidae, Graphoceratidae and Hammatoceratidae) from the Minette ironstones, southern Luxembourg
The authors present here a comprehensive taxonomic study covering the ammonites of the Toarcian part of the Minete ironstones. This study is based on 365 ammonite specimens from the collections of the National Museum of Natural History in Luxembourg, originating mostly from historical collections of the 19th century, and including material studied and published by E.W. Benecke and P.L. Maubeuge amongst others. Nine genera and 39 species are described, with a predominance of Dumortieriinae. A minor part of the fauna includes Grammoceratinae and Alocolytoceratinae, as well as Hammatoceratinae. Detailed descriptions and new illustrations are given for the type material of Dumortieria kochi (Benecke, 1905), Coteswoldia angulata (Maubeuge, 1950), Walkericeras pseudolotharingicum (Maubeuge, 1950), W. pseudoarcuatum (Maubeuge, 1950), W. hinsbergi (Benecke, 1905), W. pseudograndjeani (Maubeuge, 1950), W. dudelangense (Maubeuge, 1950), Pleydellia falcifer Maubeuge, 1950, P. pseudoaalense Maubeuge, 1950, P. funcki Maubeuge, 1950, P. arkelli Maubeuge, 1950, P. buckmani Maubeuge, 1947, P. spathi Maubeuge, 1947. The species Walkericeras lugdunensis, used as a marker of the Lugdunensis Subzone (Aalensis Zone), is considered herein a subjective junior synonym of Walkericas pseudolotharingicum Maubeuge, 1950, and hence the Pseudolotharingicum Subzone is proposed to replace the former Lugdunensis Subzone. The stratigraphical range of the studied assemblage includes the Pseudoradiosa and Aalensis zones of the Upper Toarcian, confirming thus that a large part of the Minete rocks are of Toarcian but not Aalenian age, as previously demonstrated by the works of P.L. Maubeuge, contrary to the views expressed by workers from the 19th and first half of the 20th century.
Graphoceratidés (Ammonitina) de l'Aalénien moyen (Jurassique) de Rumelange-Hutberg (Grand-Duché de Luxembourg)
The study of the ammonites belonging to the family Graphoceratidae from the Hutberg site nearby Rumelange (basin of Esch-sur-Alzete) has allowed an update on the palaeontology and stratigraphy of the upper part of the Luxembourgian Minete formation (Aalenian). 23 species are described, of which 16 are new for the Grand-duchy, and their stratigraphic position in the international reference scale is indicated. The presence of the Murchisonae and Bradfordensis zones and the Haugi, Obtusiformis, Murchisonae, Bradfordensis and Gigantea subzones is evidenced demonstrating the importance of the Hutberg site as a reference geosite for the norther margin of the Paris Basin.