From introduction: This report discusses the general geology of the Upper Mississippi Valley zinc-lead district, the distribution of ore deposits, and some relations of the ore deposits to the major geologic features.

From introduction: The principal objective of the program is to make detailed geologic maps of the areas in which important phosphate deposits in the Phorphoria formation occur. It is hoped that the maps will serve both as an aid in selecting possible sites for mining and as a basis for calculating reserves.

From abstract: Devils Tower is a steep-sided mass of igneous rock that rises above the surrounding hills and the valley of the Belle Fourche River in Crook County, Wyo. It is composed of a crystalline rock, classified as phonolite porphyry, that when fresh is gray but which weathers to green or brown. Vertical joints divide the rock mass into polygonal columns that extend from just above the base to the top of the Tower.

From introduction: The exploration project at Christmas was carried on cooperatively by the Geological Survey and U. S. Bureau of Mines. Mr. 0. M. Bishop, Engineer for the Bureau of Mines, examined the property and in his report of June 6, 1942 recommended that six holes be drilled from the 800 level of the mine. The Bureau of Mines began drilling in September 1942, and the Survey investigations began a month later. Since any ore bodies discovered below the 800 level would be inaccessible until a deeper level could be developed, the Bureau and Survey decided to explore from higher levels where resulting benefits could be more quickly realized. Drilling from the upper levels was begun early in 1943.

Abstract: This report abstracts the published information on geologic occurrence and distribution of perlite in the United States. Perlite is important in the growing light-weight aggregates industry. The geology and petrology of perlite are described and brief mention is made of mining, milling, processing, economic factors, and reserve figures where known. A table of analyses of the rhyolitic, latitic, and dacitic perlite, welded tuff, pitchstone, and obsidian is included mainly to show the water content. The index map shows known deposits and the geology of areas in which possible deposits may be found. The locations of processing plants are indicated to show their economic relationship to the deposits and to markets.

From introduction: The Stanford-Hobson area project was undertaken by the United States Geological Survey, in cooperation with the United States Bureau of Reclamation, as part of a program for the geologic mapping and investigation of mineral resources in the Missouri River basin. The field work that is the basis of the ensuing report consisted of mapping the geology and determining stratigraphic relationships in sufficient detail to evaluate the mineral resources, especially the oil and gas possibilities in the area.

From introduction: This reconnaissance study was undertaken to determine the major geologic features of the western part of Mineral County, Mont., principally in the drainage basin of the St. Regis River.

From abstract: At the request of the Council of the San Carlos Apache Tribe the U. S. Geological Survey entered into a cooperative agreement calling for a brief reconnaissance study to determine, as far as practical, the mineral potential of the San Carlos Indian Reservation. Five months of field work was done during the winter and spring of 1952-53. About 30 percent of the reservation is covered by alluvial deposits of late Tertiary, Pleistocene, and Recent age, and another 60 percent is covered by volcanic rocks of Tertiary and perhaps Pleistocene age. These rocks are younger than the major epochs of metallization in southeastern Arizona. The remainder of the area is underlain by pre-Cambrian and Paleozoic sedimentary rocks, pre-Cambrian granite, and pre-Devonian diabase.

From abstract: This report is one of a series of publications by the United States Geological Survey on the Appalachian coal, oil, and gas fields. The area described occupies 227 square miles in Allegheny, Butler, and Westmoreland Counties, in western Pennsylvania, immediately north of Pittsburgh.

From abstract: The Girdwood district has been known for about 35 years to contain placer gold, but the source of the gold in veins was not discovered until about 1909. When the Alaska Railroad was completed through Girdwood it was hoped that the improved transportation facilities would enable the lode mines to operate at a profit and also to furnish tonnage to the railroad. Production from the quartz veins, however, has been negligible, although one placer mine has been operating steadily for several years.

"To the end of 1930 Alaska, according to the records of the Geological Survey, had produced placer gold to the value of $258,962,000 from mines widely scattered throughout its length and breadth. The distribution of the placers from which the gold was recovered has been stated in more or less detail in the annual summaries published by the Geological Survey on the mineral industry of Alaska and also in its more complete reports on many of the individual mining districts. Although these summaries and reports have furnished information regarding the larger regions, they have not always given specific details regarding the smaller districts. Furthermore, there has been no recent attempt to assemble and publish in one place the scattered statistics regarding the placer-gold production by years and by regions and districts. The purpose of the present report is to set forth in condensed but comprehensive form a summary of the placer-gold production of Alaska so far as it can be determined from the available official records."

From abstract: The Curry district lies on the south flank of the Alaska Range, on the southeast side of Mount McKinley. Most of it is west of the Alaska Railroad. The eastern portion can be easily reached from several points along the railroad route, but the western portion is much more difficult of access, owing to the numerous glacial streams and the rugged topography. The relief of the area is great, the elevation ranging from 500 feet along the Chulitna River to 20,300 feet at Mount McKinley. The Chulitna River, a tributary of the Susitna River, drains the larger part of the area described. It flows in a broad valley in the eastern part of the district, and here the maximum relief is about 3,000 feet. The western part of the district is very rugged, with numerous peaks over 6,000 feet in elevation which have sheer slopes and almost unscalable pinnacles. Winding down through this maze of rugged mountains are four major valley glaciers-Eldridge, Buckskin, Ruth, and Tokichitna-and many tributary and smaller glaciers. Practically the entire district, with the exception of the higher peaks and ridges, has been glaciated. Timber grows along the main streams and extends to an elevation …

Abstract: During the spring of 1932 an opportunity was offered by the United States Navy for a geologist to accompany an expedition organized to make a reconnaissance of the western part of Alaska Peninsula and the Aleutian Islands. This expedition visited several localities the geology of which was little known. It was found, as had already been expected, that the islands west of Unimak Pass are composed mainly of basic volcanic lavas and fragmental materials, into which have later been injected dikes, sills, and considerable masses of intrusive rocks, some of which are of acidic types and of granitic texture. These westward islands are bordered both to the north and south by depressions 2,000 fathoms or more in depth, and the islands have apparently been built up from that depth by the ejection and extrusion of volcanic materials since early Tertiary time. No rocks of proved pre-Tertiary age were seen, and the only sedimentary materials present may well have been derived from the erosion of the volcanic islands after they were built up above sea level. On the Alaska Peninsula pre-Tertiary sediments through which the volcanic materials broke to the surface are abundantly present. There is evidence that all the …

From abstract: The Santa Rita mining area (pl. 1), covering 35 square miles of semiarid mountainous land, lies within the Silver City 30-minute quadrangle, Grant County, N. Mex., and includes the most productive part of the Central or Hanover mining district. Ore was produced in this district as early as 1804 and production continued intermittently for a century before the developments were undertaken that led to large-scale copper mining, which began in 1912. The output of zinc, lead, and iron increased markedly about the same time.

From abstract: The report describes the geology and coal deposits of the southwestern part of the San Juan Basin, N.Mex. The field lies northeast of the town of Gallup, on the Atchison, Topeka & Santa Fe Railway, and is an irregular tract of about 630 square miles in central and west-central McKinley County; it includes the southeast corner of the Navajo Indian Reservation.

From introduction: The present report describes the general geology and the economic resources of the [Mount Taylor Coal] field. The area adjoining this on the west was mapped by Sears; the area adjoining on the north was mapped by Dane.

From abstract: This report describes the geology and coal deposits of an area including about 1,000 square miles in southeastern San Juan, northwestern Sandoval, and northeastern McKinley Counties, in northwestern New Mexico.

From abstract: The Kantishna mining district is about 90 miles west of McKinley Park station on the Alaska Railroad. The part of the district covered by this report comprises an area of about 72 square miles in the form of a strip 6 miles wide and 13 miles long. The bedrock is mainly a metamorphic series of rocks which within the area has been differentiated into a quartz-muscovite schist and a calcareous faces that ranges from limestone to chlorite schist. A few small dikes of quartz porphyry and diabase intrude the schist. The general structure trends N. 700 E., and from an axis that extends from Eldorado Creek northeastward to Spruce Peak the schistosity dips to the northwest and southeast. It is along this axis that the heaviest mineralization has occurred.

From abstract: This report summarizes the results of a reexamination, in 1930, of the Contact mining district, in Elko County, northern Nevada. A report published as a result of a visit in 1910 summarizes the major features of the geology of the district, and the principal new data in the present paper pertain to mining development occasioned by the completion of a railroad through the camp in 1925.

From abstract: The Rosebud coal field, named from Rosebud Creek and the village of Rosebud, includes an area of about 1,050 square miles and forms a very small part of the subbituminous and lignite coal fields of eastern Montana and Wyoming and the western part of the Dakotas. It is an irregularly bounded tract lying south of the Yellowstone River in eastern Rosebud County and western Custer County and measures 50 miles from east to west and 28 miles from north to south. It adjoins the Forsyth coal field, on the west, the Ashland coal field, on the south, and the Miles City coal field, in part, on the north.

From abstract: The Richey-Lambert coal field is an area of about 900 square miles in Richland and Dawson Counties, eastern Montana, along the divide between the Missouri and Yellowstone Rivers. In this region only flat-lying continental rocks occur near the surface. About 300 feet of the Lebo shale member and about 930 feet of the coal-bearing Tongue River member of the Fort Union formation, of Eocene age, are exposed in the area. Deposits of terrace gravel at two levels in the field are tentatively correlated with the gravel on the Cypress Hills, Saskatchewan, which has been assigned to the Oligocene by the Canada Geological Survey, and with the Flaxville gravel, of upper Miocene or Pliocene age.

From abstract: This paper gives the results of a resurvey of certain areas in Montana to which renewed interest has been directed by the development recently of a market for crude phosphate rock in British Columbia, nearby.

From introduction: This report describes the mineral resources of the western part of the Arkansas coal field and considers the features of geologic structure and stratigraphy that are essential to an understanding of the nature of occurrence of the mineral resources. The area is an irregular-shaped tract of about 1,100 square miles in Scott, Sebastian, Crawford, Franklin, and Logan Counties, in west-central Arkansas.

From abstract: This report describes a rectangular area of about 2,600 square miles in Chouteau, Hill, and Liberty Counties, Mont., adjacent to the international boundary. The area is a portion of the Missouri Plateau, a section of the Great Plains province, and lies between the Highwood Mountains, Bearpaw Mountains, and Sweetgrass Hills, of north-central Montana. The southern part of the area is drained by the Missouri River and its tributary Marias River, but the northern part is drained by the Milk River. These streams are trenched in narrow valleys several hundred feet deep. The land surface between them is a rolling plain interrupted by very broad, shallow valleys that probably were eroded during the Pleistocene epoch by large streams whose courses were doubtless diverted from time to time by the continental glaciers. These valleys are now occupied only by very small creeks.