ProQuest Government Periodicals Index is your key to unlocking the wealth of material published by the United States federal government. As a publisher of information relating to diverse subjects business, agriculture, national security, the environment, nutrition, transportation and more. The federal government offers numerous magazines and newsletters with substantial research value. Government Periodicals Index helps researchers access this type of information through detailed indexing. Coverage includes: Areal geology; Economic geology; Engineering geology; Environmental geology; Extraterrestrial geology; Geochemistry; Geochronology; Geophysics; Hydrogeology and hydrology; Marine geology and oceanography' Mathematical geology; Mineralogy and Crystallography; Paleontology; Petrology; Seismology; Stratigraphy; Structural geology; and Surficial geology.