EARLY PENNSYLVANIA!! FLORA FROM WEST-CENTRAL ILLINOIS 



The material used in this study comes from the northeastern edge 

 of an outlier of Pennsylvanian strata that is separated from the main 

 area of Pennsylvanian deposits by the erosion of the La Moine River Val- 

 ley (text fig. l). The collecting sites are in northeastern Brown County, 

 Illinois (Rushville, Illinois 15-Min. Quad.; NW^ SW^ NW^ SW^ Sec. 12, 

 and NE&; SE^ NE^ SE^ Sec. 11, T. IN., R. 3 W. ) , on the bluffs of the La 

 Moine River (formerly "Crooked Creek"). One locality is along the road 

 that runs northwest-southeast and parallels the river; the exposure is 

 15 meters northwest of the turn of the road. A second locality is lo- 

 cated in a small ravine about 75 meters west of the first locality. The 

 exposures at both localities are at the same elevation and stratigraphic 

 position. The specimens described in this paper are housed in the col- 

 lections of the Illinois State Museum (ISM). 



Acknowledgments 



We wish to acknowledge the assistance received from the Spencer 



family, who donated specimens to the 



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 ILLINOIS 



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This Reporl 



Text fig. 1 - Map shoving the relation 

 of the Spencer Farm locality to the 

 outcrop area of Pennsylvanian rocks. 



Illinois State Museum and allowed 

 the authors to collect on their 

 farm. 



We wish to thank Dr. Tom L. 

 Phillips of the University of Illi- 

 nois and Dr. Sergius H. Mammay, U.S. 

 Geological Survey, for their en- 

 couragement and for reviewing our 

 manuscript. Dr. Russell A. Peppers, 

 Illinois State Geological Survey, 

 helped with paleobotanical and strat- 

 igraphic problems. Material was 

 loaned by Dr. Dwayne D. Stone, Mari- 

 etta College, Ohio, and by Dr. Herman 

 F. Becker, The New York Botanical 

 Garden. Mr. Rudolf Ewald, Datteln, 

 Germany, helped us with the deriva- 

 tion of the new specific names. Dr. 

 Leo J. Hickey, Smithsonian Institu- 

 tion, kindly supplied us with photo- 

 graphs of some of Lesquereux's type 

 specimens. 



GEOLOGY 



Erosion of the sub-Pennsylvanian 

 limestones in the area of the Spen- 

 cer Farm produced a very irregular 

 surface with relief of at least 12 

 meters. The earliest Pennsylvanian 

 deposits filled low areas only. They 

 are discontinuous and vary greatly 

 in thickness and lithology. The de- 

 posits described in this report rep- 

 resent the early filling of a ravine 

 in the Mississippian limestone and 



