Structure of the Illinois Basin The Illinois Basin is located between Illinois, Indiana, and Kentucky and has an oval structural depression in southeastern Illinois. The Illinois basin is classified as an intracratonic basin (Bois and Pelet 1982). The Illinois basin began as a rift complex that eventually failed, the New Madrid fault is associated with this rift (Hasenmueller and Comer 1994). The depositional thickness of the New Albany Shale was strongly influenced by regional deformation in southeastern Illinois (Lineback 1980). The Illinois Basin is separated from the Michigan Basin by the Kankakee Arc, which lies primarily in Indiana (Nelson 1995). To the southeast is the Cincinnati Arch (Nelson 1995). In central and southern Illinois the primary structural feature is the Eastern Interior Basin, which is a geosyncline (Hasenmueller and Comer 1994). The LaSalle anticlinal belt extends more than 200 miles from above LaSalle Illinois to beyond the eastern border of the state of Illinois (Hasenmueller and Comer 1994). The fault can be found throughout the basin and includes the New Madrid Complex (Hasenmueller and Comer 1994). Within the New Madrid complex is the Rough Creek Graben, which extends into the Reelfoot rift (Hasenmueller and Comer 1994). The Fluorspar area fault complex contains the northwest-striking Tolu arc (Buschbach and Kolata 1991). The interpretation of the fault type has some discrepancies (Trace 1974). Some interpretations show it as a high-angle normal fault, while others interpret it as a high-angle inversion and slip (Trace 1974). The Cottage Grove fault system is located in southern Illinois and has many different structures associated with it which include normal, reverse, strike-s...... center of paper......, V. 52 , P. 1291 -1303.Lineback, J.A., 1980, Coordinated Study of Devonian Black Shale in the Illinois Basin: Illinois, Indiana, and Western Kentucky: Morgantown Energy Technology Center, U.S. Department of Energy, Contract/Grant Report 1981 -1, 36 p. Lineback, J.A., 1966, Deep-water sediments adjacent to the Borden Siltstone delta (Mississippian) in southern Illinois: Champaign, Illinois State Geological Survey, Circular 401, 48 p.Nelson. N., 1995, Structural Characteristics in Illinois: Illinois State Geological Survey, Bulletin 100. Stevenson, D.L., and Dickerson, D.R., 1969, Organic Geochemistry of the New Albany Shale in Illinois: Illinois State Geological Survey Illinois Petroleum 90, p. 11.Werner-Zwanziger, U., 2005, Thermal maturity of type II kerogen from the New Albany Shale analyzed by 13C CP/MAS NMR: Solid State Nuclear Magnetic Resonance, see 27 p. 140-148