Acknowledgments

A word of appreciation is due to the following colleagues at the Illinois State Geological Survey for their assistance with this document. Bryan G. Huff provided oil production figures. Wayne F. Meents provided unpublished structure maps, well records, and geophysical data. Paul C. Heigold interpreted new seismic profiles and gave new insights on interpreting previously published geophysical data. Richard H. Howard supplied numerous structure maps, including a set of maps contoured on the Ste. Genevieve Limestone and covering most of southern Illinois. Elwood Atherton, Thomas C. Buschbach, Paul C. Heigold, Richard H. Howard, Dennis R. Kolata, Michael L. Sargent, and Janis D. Treworgy all reviewed the manuscript and maps at various stages of completion and offered countless helpful comments and suggestions. Merle Williams (independent petroleum geologist) supplied unpublished seismic and borehole data that pointed to new interpretations of several structures, notably the Ancona Anticline and Du Quoin Monocline.