A paper that reviews the Helderberg Group and its relation to the Silurian-Devotion boundary.

A report about sandstone in the black hills of Wyoming and South Dakota. It discusses the nonopaque heavy minerals found within it.

The following report describes the examinations of the nonopague heavy minerals in sandstone found in the Black Hills in northeastern Wyoming and western South Dakota. The studies were made to determine if differences in the shapes of the grains and proportions of minerals are sufficiently distinctive to be used in subdividing and correlating formations.

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.

This report presents maps and an annotated bibliography of ancient lake deposits in 11 Western States.

A report about the lower San Pedro Valley in Arizona. This report shows how mapping discrete units of the valley may lead to a broadened understanding of Cenozoic history of intermontane basins in Arizona.

From introduction: "The purpose of this report is to show how mapping of discrete units of the valley fill may lead to a broadened understanding of Cenozoic history of intermontane basins in Arizona. The area described is in the vicinity of Mammoth Arizona where deep dissection has exposed a complex sequence of terrestrial deposits and related rocks."

From introduction: The U.S. Geological Survey has conducted investigations of the geology and coal resources of the area in and adjacent to the Salyers-ville North quadrangle in the Eastern Kentucky coal field (fig. 7). The Salyersville North quadrangle lies between lat. 3745' and 37052'30'' N., and long. 8300' and 83 07'30'' E.; it is a 71/2-minute quadrangle in the southeast quarter of the Dingus 15-minute area which also includes the Dingus, Lenox, and White Oak 7 -minute quadrangles (fig. 8). The present report is the second for the 15-minute Dingus area; a report by Adkison (1957) has been published for the White Oak quadrangle and a third report is in preparation for the Lenox quadrangle. Other published reports for quadrangles in the vicinity are those by Englund (1955) for Cannel City to the west; Bergin (1962) for Seitz to the southwest; and Hauser (1953) for Paintsville to the east.

A report about the Clark Fork quadrangle which is underlain by more than 38,000 feet of low-grade metasedimentary rocks of the Precambrian Belt series. The quadrangle has both metallic and nonmetallic mineral deposits of considerable value.

This report gives a brief geological description of the Clark Fork quadrangle on the Idaho-Montana border.

A report about the Duck Creek Pass quadrangle which forms a large part of the bedrock of western Montana and adjoins other areas in which geologic studies are already completed or in progress.

This report follows geological studies of the Duck Creek Pass quadrangle, Montana during the summers of 1956 and 1957.

From introduction: This study was part of the U.S. Geological Survey's continuing study of the geology and ore deposits of the southern Black Hills, which was stimulated by the discovery of uranium deposits in sandstone in the area in 1951 (Page and Redden, 1952; Bell and Bales, 1955).

This report follows the geochemical study of bedrock soil and vegetation at an outcrop of the Phosphoria Formation of Permian age on Snowdrift Mountain, southeastern Idaho.

From introduction: This report presents a summary of the graptolite faunas of the Basin Ranges as known from the collections of the U.S. Geological Survey and the Departments of Geology of the University of California at Los Angeles and Utah State University. The collections were made in the period 1872-1958, but only a very small number of specimens have been described or illustrated in the 80 or so years elapsed.

From introduction: This report is compiled from fieldwork and available published data on the oxidized zinc deposits of Utah. Most of the deposits were examined by the author during the autumns of 1952-55 as part of a general study of oxidized zinc deposits of the Western States. In addition, several deposits were visited by geologists of the U.S. Geological Survey as a part of mineral investigation studies since 1940. In the process of obtaining this information many mining companies and individuals have been consulted.

A report about 100 square miles of metamorphosed Precambrian sedimentary and volcanic rocks in Wyoming. The district in which they are located is known for its gold, but iron deposits of high economic potential are being developed in the northwest part.

This report studies the Precambrian iron deposits and major geological features near Atlantic City, Fremont County, Wyoming.

A report about selenium and other trace metals in samples from some oxidized sandstone-type uranium deposits that demonstrate that concentrations of as much as 0.1 percent selenium are not uncommon in the immediate vicinity of uranium concentrations.

From abstract: The northern Black Hills bentonite mining district includes parts of Crook County, Wyo., Carter County, Mont., and Butte County, S. Dak. Within this district, many beds of bentonite occur interspersed with sedimentary strata of Cretaceous age that have an average total thickness of about 3,000 feet and consist chiefly of marine shale, marl, and argillaceous sandstone. The bentonite beds occur in formations ranging upward from the Newcastle sandstone to the lower part of the Mitten black shale member of the Pierre shale. Tertiary (?) and Quaternary deposits of gravel, sand, and silt are present on extensive terraces, and deposits of such materials also extend along stream courses in all parts of the district.

From introduction: This report is intended as a descriptive summary. The fieldwork on which it is based was completed in the central Western States in 1952-56, and additional studies were made in the Central and Eastern States before and after the western studies. Research and compilation were completed in 1956-59. Other reports will describe in detail the geology and origin of the oxidized zinc deposits in Colorado, Utah, Nevada, and California. (See also Heyl and Bozion, 1960.)

Introduction: "A program of geological mapping and exploratory core drilling was carried out from 1951 to 1953 by the U.S. Geological Survey on behalf of the U.S. Atomic Energy Commission to determine the areal distribution, thickness, and uranium content of coal in the eastern part of the Red Desert area, Sweetwater County, Wyo. Results of the field an laboratory studies of the distribution of uranium and other trace metals and hypotheses concerning the origin and mode of emplacement of the trace elements in the coal are presented in this report."

A report which includes 200,000 square miles in the southern part of the Williston basin of North Dakota, South Dakota, and Montana. The Devonian rocks consist mostly of marine carbonate, evaporite, and shale beds.

This report studies Devonian rocks in an approximately 200,000-square-mile area between Williston Basin, central Montana, and north-central Wyoming.