Geodatabase of the datasets that represent the three subareas of the Silurian-Devonian aquifer, Illinois, Indiana, Iowa, Kentucky, Michigan, Missouri, Ohio, Tennessee, and Wisconsin

These data were released prior to the October 1, 2016 effective date for the USGS’s policy dictating the review, approval, and release of scientific data as referenced in USGS Survey Manual Chapter 502.8 Fundamental Science Practices: Review and Approval of Scientific Data for Release. This geodatabase includes spatial datasets that represent the Silurian-Devonian aquifers in the States of Illinois, Indiana, Iowa, Kentucky, Michigan, Missouri, Ohio, Tennessee, and Wisconsin. Included are: (1) polygon extents; datasets that represent the aquifer system extent, and the entire extent subdivided into subareas, (2) raster datasets for the altitude of the top and bottom surfaces of the entire aquifer (where data are available), and (3) [...]