The upper boundary of the chekurovskii formation in the stratoregion (Lena river lower reaches): litho– and biostratigraphic criteria

New paleontological and lithological data characterizing the upper boundary of the Chekurovskii Formation are considered for the stratoregion located in the lower reaches of the Lena River, northern Siberia. We propose to accept this boundary at the bottom of a sandy bed with pebbles, considering the latter to be basal sandstones of an overlying transgressive sequence. Taking into account ammonite records, we can conclude that the boundary corresponds to a level within the Upper Bathonian Catacadoceras barnstoni Zone. The predominantly silt–sized sediments lying above (uppermost Bathonian? – Lower Callovian) can be treated an analogue of a lower part of the Innokent’evka Formation recognized in adjacent facial region.

Callovian and Oxfordian (Jurassic) teuthids (Coleoidea, Cephalopoda) from Chile

Coleoid specimens from the Jurassic of northern Chile are included in two different species ofTrachyteuthis, i.e.,T. covacevichiFuchs and Schultze, 2008 andT. chilensisn. sp., and in a new genus and a new species,Pseudoteudopsis perezin. gen. n. sp. The specimens described and figured are from two different areas in northern Chile. Those referred toPseudoteudopsis perezin. gen. n. sp. came from a locality north of Calama and are associated with ammonites indicating the lower Callovian uppermostbodenbenderito lowermostproximumzones (≈gracilisStandard Zone) of the Andean ammonite zonation. Those described asT. covacevichiandT. chilensisn. sp. came from the Cordillera de Domeyko, northeast of Taltal, and are associated with ammonites indicating the middle OxfordiantransversariumZone.