Article: Lower Carboniferous microfloras of Spitsbergen. Part two
Dispersed microspores recovered from the Culm succession (Lower Carboniferous) of Spitsberge are described in detail and an assessment is made of their value in the elucidation of problems of stratigraphies correlation. The majority of the samples studied are from the Billefjorden Sandstones (i.e. the Culm sequence c Central Vestspitsbergen), which consist typically of sandstones, together with subordinate carbonaceous shale and siltstones and minor coal seams. Detailed collections from three of the most complete sections of the Bilk fjorden Sandstones, at Birger Johnsonfjellet, Triungen, and Citadellet, present a comprehensive picture of th microfloral succession. As such, they serve as valuable local reference columns with which numerous additional samples, from a variety of localities and horizons in Spitsbergen and Bjornoya, may be correlated upon micro floral evidence. Two distinct, successive, microfloral assemblages are distinguishable within the otherwis sparsely fossiliferous Billefjorden Sandstones. The presence of numerous species recorded previously from variou horizons of the Russian Lower Carboniferous and of the Mississippian of Canada facilitates internations correlation. In terms of the standard European stages, the age of the Billefjorden Sandstones is shown to rang from Tournaisian to Upper Visean or lowest Namurian; in terms of North American (Mississippian) nomen clature, the series ranges in age from Kinderhook to lower or middle Chester. This paper includes the systematic descriptions of 115 microspore species. One new genus (Radialetes) and thirty-nine new species are proposed Another genus (Diatomozonotriletes) is validated and emended. Three probably new species are described bu not specifically named due to their insufficient representation. The remaining seventy-three species are al referable to previously described types. Consideration is given to relevant problems in dispersed-spore taxonomj botanical relationships, and to differences in microspore composition of various lithological types.