The principles to regionalise the Ordovician confacies and tectonic structures in the East Baltic area are defined. The three confacies belts and four tectonics structures have been distinguished in the East Baltic Ordovician Basin. The 44 graptolites, including 19 dendroid and 25 graptoloid species and subspecies, have been palaeontologically investigated. The nematophorous genus of Rhabdinopora by E. Eichwald (1855) is rehabilitated. A new subgenus Rhabdinopora (Dictyograptus) is investigated. The zonal graptolites scale is improved. The stratigraphy of the East Baltic Ordovician basin is based on the research done on graptolite, conodont and ostracod zones, as well the other fauna groups based on lithostratigraphical and ecoctratigraphical studies.