|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|
The 'Geologic and structure map of the Choteau 1 x 2 degree quadrangle, Montana: a digital database' report (chot250k.pdf) contains a detailed description of each attribute code and a reference to the associated map symbols on the map source materials. The GIS includes a geologic line work arc attribute table, chot250k.aat, that relates to the chot250k.con (contact look-up table), chot250k.st2 (structure look-up table), chot250k.lgu (linear geologic units table), and the chot250k.ref (source reference look-up table) files; and a rock unit polygon attribute table, chot250k.pat, that relates to the chot250k.ru (rock unit look-up table) and chot250k.ref (source reference look-up table) files; and a point attribute table, chot250kp.pat, that relates to the chot250p.sym (symbol description look-up table) and the chot250p.ref (source reference look-up table).