|St. Peter Sandstone, Illinois Basin
A number of maps show the elevation at the top of the St. Peter Sandstone, including those of Cram (1971), Hoholick (1980), Kreutzfeld (1982), and Young (1992a, b). The map of Hoholick (1980) was used in the GIS because it is regionally extensive. We then used a DEM generated from Digital Terrain Elevation Data (National Imagery and Mapping Agency, 2000) to calculate and grid the depth to top of the St. Peter Sandstone (c1stpeter).
Cram, I. H., ed., 1971, Future petroleum provinces of the United States-their geology and potential: American Association of Petroleum Geologists Memoir 15, 691 p.
Hoholick, D. J., 1980, Porosity, grain fabric, water chemistry, cement, and depth of the St. Peter Sandstone in the Illinois Basin: University of Cincinnati, Master's thesis, 72 p.
Kreutzfeld, J. E., 1982, Pore geometry and permeability of the St. Peter Sandstone in the Illinois Basin: University of Toledo, Master's thesis, 353 p.
Young, H. L., 1992a, Summary of ground water hydrology of the Cambrian-Ordovician aquifer system in the northern Midwest, United States: U.S. Geological Survey, Professional Paper 1405-A, 55 p.
___________ 1992b, Hydrogeology of the Cambrian-Ordovician aquifer system in the northern Midwest, United States: U.S. Geological Survey, Professional Paper 1405-B, 99 p.