There are almost no fossil remains of good preservation in the Jurassic marine sediments of the Upper Priamurye. However, the assembled collection makes it possible to describe some groups of fauna monographically. The present work describes the representatives of the genus Retroceramus collected in the Oshurkovskaya Formation. The age of this formation is established on the basis of the study of the whole complex of fauna collected in it and, first of all, belemnites as Middle Jurassic (Aalenian-Baiosian). The fauna described here was studied under the direction of V. I. Bodylevsky ...

Mesozoic sediments in the Upper Priamurye were first established by F. B. Schmidt in 1859. In 1887-1890, these sediments were subdivided into Lower and Middle Jurassic by L. Bacevich. Based on the first collected complex of fossil marine fauna, the age of the host sediments was dated to the Lower-Middle Jurassic by A. I. Khlaponin.V. 3. Skorokhodom in 1941 Mesozoic formations of the Upper Priamurye were dissected into two complexes: marine Jurassic sediments (Bureya Formation) and freshwater-continental Cretaceous sediments (Nikan Formation) ...