The Geologic Atlas of the United States is a map folio series produced by the USGS from 1894 to 1945. Each folio includes a topographic and several thematic maps for each quad in the folio along with text pages describing the geology and economic geology for the mapped areas. Only 220 odd folios were produced, so the area covered is very limited.

Lot includes: Colorado Springs Folio Colorado, 1916; Needle Mountains Folio Colorado, 1905; Pikes Peak Folio Colorado, 1894; Silverton Folio Colorado, 1905. Superb collection of early geological maps. The Colorado folios are some of the best in the series.

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Condition: A

Minor flaws and soil on covers only.