Search for all types of maps, images, and publications in the United States Geological Survey (USGS) Publications Warehouse. The USGS is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, and the natural hazards that threaten it. The organization has four major science disciplines, concerning biology, geography, geology, and hydrology.

"Established in 1888, The Geological Society of America provides access to elements that are essential to the professional growth of earth scientists at all levels of expertise and from all sectors: academic, government, business, and industry."

GEOLEX is a search tool for lithologic and geochronologic unit names.