Benthic Foraminifera Biostratigraphy and Sedimentation Fiatures of the Western Sakhalin Upper Eocene

New data on micropaleontological and lithological characteristics of Eocene deposits exposed along the Avgustovka River near the village of Boshnyakovo, Western Sakhalin are presented. For the first time, benthic foraminifera were found in these deposits and it was concluded that they are of middle-late Eocene age. Analysis of the taxonomic composition of the foraminifera assemblage, as well as the material composition of the rocks, allowed us to assume that these strata were formed within a relatively deep-water marine basin, which periodically supplied volcanic material in the form of tuffs.