GeoRef database, established in 1966 by the American Geosciences Institute(AGI), contains citations and abstracts to more than 3,500 journals in 40 languages as well as new books, maps, conference papers, reports and theses. Covers the geology of North America from 1693 to the present and the geology of the rest of the world from 1933 to the present. The database includes references to all publications of the U.S. Geological Survey. Masters' theses and doctoral dissertations from US and Canadian universities are also covered. Major areas of coverage include 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, surficial geology.