The siliciclastic Bajocian–Bathonian Pelion Formation of Tværdal, Geographical Society Ø, East Greenland, is dominated by shallow-marine sandstones, which yielded 22 bivalve taxa representing 18 genera; these are described and figured here. The type species of the subgenus Strimodiolus, Modiolus (Strimodiolus) elongatus Fürsich, 1982, is a junior homonym of Modiola elongata Swainson, 1821 and is replaced by M. (Modiolus) milnelandensis nom. nov. Infaunal taxa dominate in terms of abundance and species richness, and several of the semi-infaunal (e.g., Strimodiolus, Cyrtopinna) and deep-burrowing (Pleuromya) bivalves are preserved in life position, suggesting periodical high sedimentation rates below the fair-weather wave-base during deposition of most of the formation

Here in the first part of this publication we discuss the possibilities for the selection of a GSSP for the Berriasian Stage of the Cretaceous System, based on the established methods for correlation in the Tithonian/Berriasian interval. This will be followed, in the second part, by an account of the stratigraphic evidence that justifies the locality of Tre Maroua (Hautes-Alpes, SE France) as the proposed GSSP. Here we discuss the possibilities for correlation in the historical J/K boundary interval, and the evolution of thinking on the positioning of the boundary over recent generations, and in relation to research in the last ten years. The Tithonian/Berriasian boundary level is accepted as occurring within magnetosubzone M19n.2n. The detailed distribution of calpionellids has been recorded at numerous sites, tied to magnetostratigraphy, and the base of the calpionellid Alpina Zone is taken to define the base of the Berriasian Stage. This is at a level just below the distinctive reversed magnetic subzone M19n.1r (the so-called Brodno reversal). We discuss a wide range of magneto­stratigraphic and biostratigraphic data from key localities globally, in the type Berriasian areas of France and wider regions (Le Chouet, Saint Bertrand, Puerto Escano, Rio Argos, Bosso, Brodno, Kurovice, Theodosia etc.). The characteristic datums that typify the J/K boun­dary interval in Tethys and its extensions are detailed, and the correlative viability of various fossil groups is discussed. The boundary level is correlated to well-known J/K sections globally, and a series of secondary markers and proxies are indicated which assist wider correlation. Particularly significant are the primary basal Berriasian marker, the base of the Alpina Subzone (marked by dominance of small Calpionella alpina, Crassicollaria parvula and Tintinopsella carpathica) and secondary markers bracketing the base of the Calpio­nella Zone, notably the FOs of the calcareous nannofossil species Nannoconus wintereri (just below the boundary) and the FO of Nannoconus steinmannii minor (just above). Notable proxies for the boundary are: 1) the base of the Arctoteuthis tehamaensis Zone in boreal and subboreal regions, 2) the dated base of the Alpina Subzone at 140.22 ±0.14 Ma, which also gives a precise age estimate for the system boundary; and 3) the base of radiolarian “unitary zone” 14, which is situated just above the base of the Alpina Subzone.

The coarse-ribbed and big-sized Arietites solarium (Quenstedt, 1883) is one of the largest-grown and most iconic ammonite taxa in the entire Swabian Lower Jurassic; however, despite previous revisions including the designation of a lectotype, there has been some confusion concerning its correct identification, and its type horizon within the Lower Sinemurian Arietenkalk Formation was not exactly known. Arietites solarium characterises the herein introduced solarium Biohorizon of the upper Bucklandi Zone of the Sinemurian. For nomenclatorial stability, we designate a neotype based on the only surviving specimen of Quenstedtʼs original type series. In addition, we provide a preliminary succession of recognized biohorizons in the Lower Sinemurian of Swabia, which will make correlations with other areas more reliable.

Twenty six samples from the sections at Flodigarry and Digg at Staffin Bay, Isle of Skye, northern Scotland, spanning the stratigraphical interval from the uppermost Oxfordian to the lowermost Kimmeridgian were examined for their calcareous nannofossil content. The study revealed the presence of an assemblage typical of the nannofossil zone NJ15 of the northern European zonation.

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The new monotypic ammonite genus Xenosphinctes (type species: Xenosphinctes berkai n. sp.) is established. It is recorded from the Upper Jurassic, Early Tithonian, Hybonotum Zone, Riedense Subzone, eigeltingense α horizon from the Talmühle, N of Engen, Baden-Württemberg, SW Germany.