|Description||The paper version of The geology of the Challis 1°x2° quadrangle, was compiled by Fred Fisher, Dave McIntyre and Kate Johnson in 1992. The geology was compiled on a 1:250,000 scale topographic base map. TechniGraphic System, Inc. of Fort Collins Color|
|Originators||Fisher, F. S.; McIntyre, D. H.; and Johnson, K. M.|
|Publication||U.S. Geological Survey Miscellaneous Investigations Series Map I-1819|
Polygons are given a general type and formation name; arcs are given a general type, dikes are also assigned a unit symbol. Points are given a general type. These values are currently listed in files *.tbl accompanying the ArcInfo interchange files.