Generalized Geologic Map of the Conterminous United States
http://pubs.usgs.gov/atlas/geologic/

USGS


This site from the USGS features a geologic map of the United States using data prepared for publication in the National Atlas of the United States. There are explanations, documentations, and PDF files presenting the geologic map and a map unit chart, plus archives of ArcInfo files in several formats.

This resource is referenced here:
Subject: Geoscience:Geology
Resource Type: Audio/Visual:Maps, Datasets and Tools:Datasets
Special Interest: GIS
Data Derived: Data Derived
Data Source: Observational Data
Science Background Required: Basic scientific background required
Topics: Earth surface