The accompanying map shows the tungsten deposits of the United States (exclusive of Alaska and Hawaii). The relative importance of the deposits, groups, or districts is shown by four symbols, indicating tungsten contents of: (1) greater than 10,000 short tons of tungsten metal, (2) 10,000 to 500 tons, (3) 500 to 10 tons, and (4) less than 10 tons. In assigning size, production plus estimated reserves were taken into account, and also, for some deposits or areas, the presence of tungsten in large quantity but very low concentration.
The map symbols, plotted to the nearest minute, make no distinction between individual deposits and groups of deposits or districts; about 590 map symbols represent several times this number of deposits because many symbols stand for clusters of deposits spaced too closely to show individually at the scale used. All localities are numbered consecutively in each state and are identified in the Locality Index. Unpublished information has been used extensively. The tungsten data for Colorado, Idaho, Montana, New Mexico, South Dakota, Texas, Utah, and Wyoming were compiled by Tweto, and those for the remaining states by Lemmon.
