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Jeffery T. Silkwood

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The geologic and structure map of Choteau 1 x 2 degreequadrangle (Mudge and others, 1982) was originally converted toa digital format by Jeff Silkwood (U.S. Forest Service andcompleted by the U.S. Geological Survey staff and contractor atthe Spokane Field Office (WA) in 2000 for input into ageographic information system (GIS). The resulting digitalgeologic map (GIS) database can be queried in many ways toproduce a variey of geologic maps. Digital base map data files(topography, roads, towns, rivers and lakes, etc.) are notincluded: they may be obtained from a variety of commercial andgovernment sources. This database is not meant to be used ordisplayed at any scale larger than 1:250,000 (e.g. 1:100,000or 1:24,000....
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The digital ARC/INFO databases included in this directory provide a geologic map GIS database of the Absaroka-Beartooth study area (ABSA), a tract of approximately 1.4 million acres of National Forest land in southwestern Montana. The ABSA is adjacent to the northern part of Yellowstone National Park, and includes southeastern parts of Gallatin National Forest and western parts of the Custer National Forest. The geologic map was originally prepared to accompany a U.S. Geological Survey evaluation of the mineral resource potential within the ABSA. The results of this mineral resource assessment were published as U.S. Geological Survey Open-File Report 93-207 and the geologic map was plate 1 of this report. The enclosed...
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The digital ARC/INFO databases included in this directory provide a geologic map GIS database of the Custer National Forest in the Pryor Mountains of south-central Montana. The geologic map area comprises approximately 122 square miles (316 square kilometers) of National Forest lands, located 40 miles (64 kilometers) south of Billings, Montana. This geologic map was originally prepared to accompany a U.S. Geological Survey evaluation of the mineral resource potential of the Custer National Forest in the Pryor Mountains. The results of this mineral resource assessment were published as U.S. Geological Survey Open-File Report 96-256. This ARC/INFO database was created from figure 2 (p. 4) of that report.
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The geology of western and northern Gallatin National Forest was mapped in two parts as part of an evaluation of its mineral resource potential by the USGS. Previously, the western part was released as Map A and the northern part as Map B of USGS Geologic Investigations Series Map I-2584. These maps were compiled, digitized, and produced using the USGS software program GSMAP. All the original source maps were simplified on mylar overlays, digitized at their original map scales and projections, and then merged into the final maps. After editing, the digital maps were filtered to remove all points not necessary for improving resolution at a scale of 1:126,720 (2 mi per in., the scale used by the USDA Forest Service)....
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The geology of western and northern Gallatin National Forest was mapped in two parts as part of an evaluation of its mineral resource potential by the USGS. Previously, the western part was released as Map A and the northern part as Map B of USGS Geologic Investigations Series Map I-2584. These maps were compiled, digitized, and produced using the USGS software program GSMAP. All the original source maps were simplified on mylar overlays, digitized at their original map scales and projections, and then merged into the final maps. After editing, the digital maps were filtered to remove all points not necessary for improving resolution at a scale of 1:126,720 (2 mi per in., the scale used by the USDA Forest Service)....
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