Genus Vestigisporites 42 



Genus Wilsonites 42 



Miscellaneous small spores 42 



Description of large spores and megaspores 46 



Genus Monoletes 46 



Genus Spencerisporites 46 



Genus Triletes 46 



Description of other microfossils 46 



Hystrichosphaeridea 46 



Scolecodonts 47 



Incertae sedis 47 



Genus Centonites 47 



Distribution of small spore genera 48 



Spores of the Trivoli Cyclothem 48 



Macoupin County, Illinois 48 



Franklin County, Illinois 49 



Spores of the Fithian Cyclothem, Vermilion County, Illinois 55 



Spores of the Henshaw Formation, Union County, Kentucky 57 



Conclusions 58 



Relation of spore distribution to lithology 59 



Relation of spore recovery to lithology 61 



Summary 62 



Description of geologic sections 67 



References 70 



Plates and explanations 73 



ILLUSTRATIONS 



Text Figure Page 



1. Location of stratigraphic sections sampled in Illinois and Kentucky . . . . 10 



2. Rock stratigraphic and cyclical classification of McLeansboro strata of part of 



Illinois and of equivalent strata of western Kentucky 11 



3. Columinisporites ovalis sp. nov 16 



4. Crassispora plicata sp. nov 17 



5. Laevigatosporites spinosus sp. nov 25 



6. Latipulvinites kosankii sp. nov 26 



7. Punctatisporites brevivermiculatus sp. nov 29 



8. Punctatisporites patulus sp. nov 32 



9. Punctatisporites corona sp. nov 33 



10. Raistrickia kentuckiensis sp. nov 36 



11. Trivolites laevigata sp. nov 41 



12. Centonites symmelricus sp. nov 47 



13. Relative abundance of small spores, by genera, in the Trivoli Cyclothem and 



immediately overlying strata, Macoupin County, Illinois 50 



14. Relative abundance of small spores, by genera, in the Trivoli Cyclothem, 



Franklin County, Illinois 



04 



15. Relative abundance of small spores, by genera, in the Fithian Cyclothem, 



Vermilion County, Illinois 54 



16. Relative abundance of small spores, by genera, in the Henshaw Formation, 



Union County, Kentucky .56 



