Abstract
Early Eocene microfossils from carbonate-cemented volcanic ashes (cementstones) of the Greifswalder Oie island, southern Baltic Sea, have been investigated. In addition to numerous siliceous microfossils such as diatoms, silicoflagellates and sponge spicules, a monospecific foraminiferal assemblage ( Ammobaculites oieensis sp. nov.) is recorded and documented here in detail. The new species is characterised by an agglutinated wall structure consisting of volcanic ash shards and quartz and feldspar grains, as well as by its size and number of chambers, and by an initially planispiral test shape that becomes uniserial.