CONTENTS 



Page 



Introduction ' 



Purpose and scope 8 



Previous investigations 9 



Preparation and examination of samples 10 



Spore development and morphology H 



Descriptions of megaspores and "large" spores 15 



Genus Triletes 15 



Genus Triletes? 48 



Genus Cystosporites 50 



Genus Spencerisporites 54 



Genus Calamospora 59 



Genus Monoletes 61 



Genus Parasporites 63 



Descriptions of "small" spores 63 



Genus Punctatisporites 63 



Genus Reticulatisporites 64 



Genus Renisporites n. gen 64 



Other microfossils of the plus 65-mesh residues 67 



Sporangial masses of Densosporites 67 



Seed membranes 6/ 



Miscellaneous plant microfossil 



68 



Animal (?) membranes 68 



Location of samples 69 



Spore distribution /J 



Introduction '^ 



Mississippian System 73 



Chester Series '•* 



Pennsylvanian System 



Caseyville Group '' 



Tradewater Group °^ 



Carbondale Group 89 



McLeansboro Group -^ 



Discussion 



Upper Mississippian "^ 



Pennsylvanian 



References 



Plates and Explanations 103 



ILLUSTRATIONS 



Text Figure Page 



1. Orientation of radially symmetrical spores 



2. Orientation of bilaterally symmetrical spores 



3. Scatter diagrams illustrating megaspore shrinkage upon drying 14 



4. Length-breadth measurements of spores of Renisporites conjossus 6:> 



5. Length-breadth proportions of spores of Renisporites conjossus 65 



6. Illinois counties from which macerated coal samples were examined 68 



7. Stratigraphic occurrence of spores in upper Mississippian and lowermost Pennsylvan- 



ian rocks ."*.*'" 



8. Stratigraphic occurrence of seven genera and spores of five sections of Triletes in upper 



Mississippian and Pennsylvanian rocks 



9. Spore distribution chart •• • * ■ 



