Seamless Data Distribution System
http://www.webgis.com/usgsseam.html

USGS


This site from the USGS and the EROS Data Center (EDC) presents the Seamless Data Distribution System (SDDS). The site is the ultimate location for exploration and data retrieval from both the United States and international locations. The site features free data downloads, user defined datasets and area, data acquisition from different government hosts, and elevation point and profile tools.

This resource is referenced here:
Subject: Geoscience:Geology
Resource Type: Audio/Visual:Images/Illustrations, Maps, Datasets and Tools:Tools, Datasets
Data Derived: Data Derived
Data Source: Observational Data
Science Background Required: Basic scientific background required