The NSS Bulletin - ISSN 1090-6924
Volume 48 Number 1: 1-7 - June 1986
A publication of the National Speleological Society

Stratigraphic Sections in the Ste. Genevieve Formation (Middle Mississippian) Exposed in Garrison Chapel Karst Area Caverns-Western Monroe County, Indiana
Garre A. Conner

Abstract

The Ste. Genevieve Formation and related strata in the Blue River Group comprise more than 250 feet of Middle Mississippian carbonate deposition across the Indiana flank of the Eastern Interior Basin in Valmeyeran seaways. Karst outcrop and cavern exposures of these strata occur in the strike-oriented Crawford Upland physiography. Karst valleys are a striking topographic feature along the margin of this rugged escarpment of Chester clastic strata.

Twenty-five miles of surveyed subterranean passages lie beneath the Garrison Chapel karst area occupying a western portion of a karst valley in the headlands of Indian Creek; an area of fifteen square miles. Descriptions of drainage and cavern systems extending from sinkholes to springs have been the focus of more previous investigations.

The bedrock floor of this karst valley is locally accordant with a continuous horizon of lithographic limestone ranging nine to fifteen feet in thickness; within the lower Levias Member as indicated by structure mapping at five measured cavern sections. This lithographic unit is a decisive structural reference for mapping thickness and countinuity variation in algal, breccia, and sandy facies in the overling Paoli and Popcorn Beds and the subjacent Rosiclare Member.

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