Findings from a study of trilobite fossils This publication, Trilobites of the Tremadoc Bjorkasholmen Formation in the Oslo Region, Norway, is Number 47 within the Fossils and Strata series. This publication offers updated descriptions of trilobite fauna of the upper Tremadoc Bjorkasholmen Formation. It also addresses the regional and vertical distribution of the fauna. The international Fossils and Strata series features monographs in palaeontology and biostratigraphy with taxonomic descriptions. The series is owned by and published on behalf of The Lethaia Foundation in cooperation with the Scandinavian countries.