Because of the extensive, economically important coal deposits of the Pennsylvanian System, more data have been published on the plant microfossils of that period than any other period. Relatively little is known, however, of the palynology of Pennsylvanian rocks other than coal. In light of this, the present study is concerned with the investigation of the small spores of coal as well as marine and nonmarine strata of several upper Pennsylvanian (McLeansboro Group) cyclothems of Illinois and western Kentucky ... The purposes of this study are first, to identify and describe spores and pollen from a wide range of lithologies ... The second aim is to determine the distribution and range of spore-pollen taxa in the various kinds of sediment ... A third purpose of this study is to report the presence in upper Pennsylvanian rocks of bisaccate gymnospermic pollen and prepollen grains which became such a conspicuous element of the plant microfossil assemblages in Permian sediments.