The distribution of Densospores

Abstract

Densospores include species of the miospore genera Cingulizonafes (Dybova & Jachowicz), Crisfafisporites (Potonie & Kremp), Densosporites (Berry) and Radiizonates Staplin & Jansonius from the literature of Europe and North America, and Euryzonotriletes Naumova, Hymenozonotriletes Naumova and Trematozonotrilefes Naumova from the Russian literature. An account is given of the taxonomic position of densospores and of their morphographic variation in different parts of the column. Densospores have been recorded in large numbers, mainly from coal seams, from the Devonian to the Permian of the northern hemisphere. The geographical distribution of these occurrences forms the subject matter of the present paper. In general densospores first occur in abundance in more northerly regions and are displaced gradually southwards during the Carboniferous. They are most common and have the longest ranges, in area of slow subsidence.