Scope and Purpose of Work: The quadrangle was mapped as part of the U.S. Geological Survey program of classifying and evaluating lands in the Public Domain. Mineral rights for coal had been retained in parts or all of Tps. 2 and 3 N., Rs. 77, 78, and 79 W. These areas are in part underlain by sedimentary rocks of Late Cretaceous(?) and early Tertiary age (Middle Park Formation), and in North Park these rocks are called the Coalmont Formation and contain coal. The chief purpose of the work was to map and study any coal beds found and to make a detailed geologic map that can be used as part of a geological atlas of the United States.

Analysis of geologic, hydrologic, and geophysical data obtained in and around Yellow Creek core hole No. 1, Rio Blanco County, Colorado, indicate a 1,615-foot section of oil shale was penetrated by the hole. Geophysical log data indicate the presence of 25 gallons per ton shale for a thickness of 500 feet may be marginal. The richest section of oil shale is indicated to be centered around a depth of 2,260 feet. Within the oil shale the interval 1,182 to 1,737 feet is indicated to be relatively structurally incompetent and probably permeable. Extension of available regional hydrologic data indicate the oil shale section is probably water bearing and may yield as much as 1,000 gallons per minute. Hydrologic testing in the hole is recommended.

From introduction: This is one of a series of three reports on airborne radioactivity surveys in the United States. The reports contain the 185 airborne anomaly maps issued by the U. S. Atomic Energy Commission as a result of the AEC's aerial surveying program conducted from March 1952 to June 1956; two ground reconnaissance maps of Utah also are included. Most of the reconnaissance was done in the western United States.

From Abstract: "For about 1500 spectral lines of diatomic molecules observed by coherent radiation techniques, measured frequencies, assigned quantum numbers, and newly computed intensities are given."

Abstract: This report is a synthesis of published and unpublished data on the rocks of the Anadarko basin.

From Introduction: "Detailed reports on various phases of the oil-shale mining research program have been published by the Bureau of Mines as Reports of Investigations, and numerous articles prepared by the mine staff have been published in the technical press. Summarizes of some of these publications are included in this report with other information not previously published."

From abstract: Deposits of oxidized zinc ore are widely distributed in the western part of Colorado in the Rocky Mountains west of the Front Range and in the uplifted plateaus that border the main area of the Colorado Plateau. The principal production and reserves are restricted to several mining districts--Leadville. Aspen, Monarch, Spring Creek. Horseshoe, Tomichi, Tincup, and Rico--in all of which limestone and dolomites of Paleozoic age are the main host rocks. One deposit, that of the Sedalia mine near Salida has produced commercial quantities of oxidized zinc-copper ore from noncarbonate host rocks, but other known deposits in noncarbonate rocks are mostly low grade.

From purpose of the report: A detailed office study of modern topographic and geologic maps and aerial photographs of Yampa Canyon and its environs in the Uinta Mountains.

Discussing the geologic setting of the Foothills Mine, Idledale District, Jefferson County, Colorado

Report issued by the Bureau of Mines over the Iron Mountain magnetite deposits. As stated in the introduction, "magnetic, gravity, and geologic surveys were made to permit an estimate of the extent and magnitude of the Iron Mountain, Colorado, titaniferous magnetite deposit" (p. 1). This report includes tables, maps, and illustrations.

A report about the known facts about the minerals that make up the rocks, soils, and ore deposits of Colorado.

"A summary of the first 100 years of published knowledge, including the chief occurrences of 445 mineral species."

Report issued by the Bureau of Mines over heavy sandstone deposits in the Four-State area of the U.S. Details of the geology and an estimate of resources are presented. This report includes tables, maps, and illustrations.

Report issued by the U.S. Bureau of Mines discussing sinking and excavation of large-diameter access shafts. As stated in the introduction, "this information circular describes the application of modern methods and equipment in sinking a vertical, 916-foot-deep by 16-foot-diameter, concrete-lined access shaft for the Harold D. Roberts tunnel near Montezuma, Colo." (p. 1). This report includes maps, tables, illustrations, and photographs.

From introduction: The greatest known potential oil resource in the world occurs in the oil shale of the Green River formation, and the richest and thickest deposits occur within the area of this report. The purpose of this investigation was to obtain data on the stratigraphic distribution and areal extent of the oil-shale beds and to estimate the potential oil resources in the area.

Report issued by the U.S. Bureau of Mines discussing uranium mining costs and methods on the Colorado Plateau. Costs of labor, transportation, and explosives, as well as mining methods and practices used, are presented. This report includes maps, tables, illustrations, and photographs.

From introduction: The study is essentially an economic evaluation of the construction and operation of nuclear power plants at several designated military installations where increased power generating capabilities of 5 to 40 mwe may be required by the Government during the period 1963 through 1970.

From abstract: The Little Cone quadrangle includes an area of about 59 square miles in eastern San Miguel County in southwestern Colorado. The quadrangle contains features characteristic of both the Colorado Plateaus physiographic province and the San Juan Mountains, and it has been affected by geologic events and processes of two different geologic environments.

From abstract: The fluorspar deposits in the Northgate district, Jackson County, Colo., are among the largest in Western United States. The mines were operated intermittently during the 1920's and again during World War II, but production during these early periods of operation was not large. Mining was begun on a larger scale in 1951, and the district has assumed a prominent position among the fluorspar producers in the United States. Within the Northgate district, Precambrian metamorphic and igneous rocks crop out largely in the Medicine Bow Mountains, and later sedimentary rocks underlie North Park and fill old stream valleys in the mountains.

Report issued by the Bureau of Mines over studies conducted on Larimer County pegmatite deposits. Descriptions of the deposits are presented. This report includes tables, maps, photographs, and illustrations.