U.S. Geological Survey Library
Users can: search the U.S. Geological Survey Library online catalog; find out about USGS Library services and collections; and read answers to frequently asked questions about availability of USGS publications, field record materials, mapping notes for USGS topographic maps, historical topographic maps, U.S. aerial photographs, geologic maps, wetlands maps, flood maps, and digital map data.USGS National Geologic Map Database
This is a prototype and searchable version of the National Geologic Map Database. The database consists of bibliographic citations for geologic maps of the United States and its territories. Users can search the database by state or territory and also by geologic themes.