This dataset contains a digital version of the Geologic Map of the
United States, originally published at a scale of 1:2,500,000 (King and
Beikman, 1974b). It excludes Alaska and Hawaii. In addition to the
graphical formats, the map key is included in ASCII text.
A geographic information system (GIS) allows combining and overlaying of
layers for analysis of spatial relations not readily apparent in the
standard paper publication. This disc contains only
geology. However, digital data on geology, geophysics, and geochemistry
can be combined to create useful derivative products-- for example, see
Phillips and others (1993).