From abstract: Paricutin is 320 kilometers west of Mexico City and is reached by air, rail, or paved highway to Uruapan, Michoacan, and thence by 37 kilometers of paved and dirt road to lava-destroyed San Juan Parangaricutiro, 5 kilometers north of the cone.

From introduction: The purpose of this study was to investigate the quantity and quality of [Central Ceara, Brazil] magnesite, and the writer concludes that this group of deposits constitutes one of the major reserves of high-grade magnesite in the Western Hemisphere. The ore could be used in the production of any commercial grade of magnesia with little or no beneficiation. Soil and alluvial overburden is thin between widespread outcrops, so all the deposits could be mined from open pits.

From abstract: This report summarizes the economic possibilities of the tin deposits of the Estado de Durango, Mexico. It describes in detail many deposits in the leading districts, which were examined in 1944, and briefly reviews some reports on undeveloped occurrences in the southern and western parts of the State. The general conclusion is that tin will continue to be produced by hand methods for many years, but probably at a decreasing rate, because the placer grounds which have always produced the greater part of the tin are faced with gradual exhaustion.

Including a list of all known volcanoes and a summary of activity betwen 1760 and 1948.

The following report describes the different volcanoes of the Paricutin Region.

From foreword: This bulletin is the second of the series "Contributions to Geochemistry" which was begun in 1946 with Bulletin 950, "Contributions to Geochemistry, 1942-45". This series is the successor to earlier ones, also published as U. S. Geological Survey Bulletins, "Report of work done in the Division of Chemistry and Physics" (1879-1893), "Contributions to chemistry and mineralogy from the laboratory of the United States Geological Survey" (1900), "Contributions to mineralogy from the United States Geological Survey" (1905), and "Mineralogical Notes" (1911-16).

From abstract: Gypsum-bearing rocks crop out in Gypsum and Yellow Jacket Gulches, on Sheep Mountain, which is about 90 miles northeast of Anchorage, Alaska. The gypsiferous rock occurs in deposits of irregular shape in the greenstone. Both the gypsiferous rock and the greenstone are hydrothermal alteration products of the volcanic rocks of Jurassic age which comprise the bulk of the mountain. Near-surface samples of the gypsiferous rock contained an average of 25 to 30 percent gypsum ; some contained as much as 50 percent. Quartz, alunite, clay, sericite, and pyrite are contaminating constituents of the ore. Six of the largest and most accessible of the gypsum deposits were mapped and calculations show that three of the deposits contain an aggregate of approximately 311,000 short tons of indicated gypsiferous rock and four of the deposits contain 348,000 short tons of inferred gypsiferous rock.

From abstract: The origin of the gneissic rocks on the eastern border of the Idaho batholith in the Bitterroot Range, near Hamilton, Mont., has long been in dispute. Lindgren regarded these rocks as the product of stresses related to a normal fault along the front of the range with an eastward dip of about 150. He thought both the hanging wall and the footwall had moved, with a total displacement along the fault plane of at least 20,000 feet. The faulting was believed to have been so recent as to be a major factor in the present topography. Langton appears to accept the concept of faulting but to regard the gneissic rocks as formed much earlier from a granitic rock that was more silicic and older than the Idaho batholith.

From abstract: Most of the formations in the Wray area are fair foundation materials, although good construction materials are scarce. The gravel of the Grand Island formation and the gravels in the Ogallala formation contain large quantities of clay, silt, sand, and calcium carbonate, and have very few pebbles larger than one-half inch in diameter.

From abstract: Two deposits of high-grade gypsum are located near tidewater at Iyoukeen Cove, on the northeastern part of Chichagof Island, southeastern Alaska. A group of claims, formerly operated by the Pacific Coast Gypsum Co., was acquired by the Kaiser Gypsum Division of Kaiser Industries, Inc., during World War II. Claims at the other deposit are held by Dave Housel of Juneau and Seattle, Washington, in the name of the Gypsum-Camel group.

From introduction: This report describes the destructive effect of permafrost on cultivated fields and delineates the parts of the Fairbanks area which are least suitable for agriculture because of the character of the underlying permafrost. Studies by the author indicate that agriculture will be affected by similar permafrost conditions throughout areas on the north side of the Tanana Valley within 100 miles of Fairbanks.

From abstract: The central part of the Commodore fault system is in the western Kentucky fluorspar district, in Crittenden County, about 6 miles northwest of Marion. It has yielded from 30,000 to 40,000 tons of crude fluorspar and nearly 20,000 tons of zinc ore. Limestones, sandstones, and shales of the Meramec, Chester, and Pottsville groups of Carboniferous age crop out as relatively flat-lying beds, except near faults. The rocks are transected by high-angle normal faults. The main faulted zone is the Commodore fault system, which displaces the beds from 1,500 to 2,000 feet. The principal vein minerals are fluorite, calcite, smithsonite, sphalerite, and galena. Fluorite and smithsonite are the chief ore minerals, occurring as lenses along the faults. The mines have been worked since 1892, but most of the workings are caved or filled with water.

Abstract: The Moore Hill fault system in the central part of the Kentucky-Illinois fluorspar field is about 26 miles long. Fluorspar has been produced from a part nearly 5 miles long, and since mining began in 1899 this system has yielded more than 300,000 tons of fluorspar. Lead and zinc sulfides commonly are found in the ore, but only rarely do they occur in sufficient quantity to be worth recovering. The productive part of the fault system was mapped and the properties and principal mines described. The high-angle normal faults of the system cut limestones, sandstones, and shales of Mississippian age. Stratigraphic displacements range from less than a foot to as much as 550 feet. The fluorspar bodies are sporadically distributed in veins of calcite and fluorite along the faults.

From abstract: The Jonesville district is in central Lee County in the extreme southwest corner of Virginia. It includes an area that is 25 miles long from northeast to southwest and averages 6 miles in width. Most of the district lies within a broad lowland named the Powell Valley, but the district includes Wallen Ridge, which bounds Powell Valley on the southeast.

From abstract: This paper describes the geology of a part of the Alaska Range, extending from the Delta River to the international boundary between Alaska and Canada, and of an additional area that includes part of the Wrangell Mountains and the upper Copper River valley.

From introduction: This paper describes the geology of the Prince William Sound region, a part of south-central Alaska. It deals with the rocks of a section of the Coast Ranges that has been studied by various geologists over a period of many years and still offers basic problems that are unsolved. Prince William Sound is well known for its mining activities, but the intention here is to describe the areal and stratigraphic geology of the district rather than its mineral resources and to present a statement that will serve as a report of progress and a basis for more detailed field work.

Abstract: The uranium deposit at the Silver Cliff mine near Lusk, Wyo., consists primarily of uranophane which occurs as fracture fillings and small replacement pockets in faulted and fractured calcareous sandstone of Cambrian(?) age. The country rock in the vicinity of the mine is schist of pre-Cambrian age intruded by pegmatite dikes and is unconformably overlain by almost horizontal sandstone of Cambrian(?) age. The mine is on the southern end of the Lusk Dome, a local structure probably related to the Hartville uplift. In the immediate vicinity of the mine, the dome is cut by the Silver Cliff fault, a north-trending high-angle reverse fault about 1,200 feet in length with a stratigraphic throw of 70 feet. Uranophane, metatorbernite, pitchblende, calcite, native silver, native copper, chalcocite, azurite, malachite, chrysocolla, and cuprite have been deposited in fractured sandstone. The fault was probably mineralized throughout its length, but because of erosion, the mineralized zone is discontinuous. The principal ore body is about 800 feet long. The width and depth of the mineralized zone are not accurately known but are at least 20 feet and 60 feet respectively. The uranium content of material sampled in the mine ranges from 0.001 to 0.23 percent uranium, …

From abstract: Carnotite-bearing sandstone and claystone have been found in the Chadron formation of the White River group of Oligocene age in the southern part of the Slim Buttes area, Harding County, S. Dak. The carnotite is an efflorescent yellow coating on lenticular silicified sandstone. Locally, the mineralized sandstone contains 0.23 percent uranium. The uranium and vanadium ions are believed to have been derived from the overlying mildly radioactive tuffaceous rocks of the Arikaree formation of Miocene age. Analyses of water from 26 springs issuing from the Chadron and Arikaree formations along the margins of Slim Buttes show uranium contents of as much as 200 parts per billion. Meteoric water percolating through tuffaceous rocks is thought to have brought uranium and other ions into environments in the Chadron formation that were physically and chemically favorable for the deposition of carnotite.

Abstract: Most of the uranium deposits in the Uravan and Gateway mining districts are in the persistent upper sandstone stratum of the Salt Wash member of the Morrison formation. Areas in which this stratum is predominantly lenticular have been differentiated from areas in which the stratum is predominantly nonlenticular. The most favorable ground for uranium deposits is in areas of lenticular sandstone where the stratum is underlain by continuous altered greenish-gray mudstone. Ore is localized in scour-and-fill sandstone beds within favorable areas of lenticular sandstone. Regional control of the movement of ore-bearing solutions in the principal ore-bearing sandstone zone is indicated by belts of discontinuously altered mudstone transitional in a northerly and southerly direction from an area of unaltered mudstone to areas of continuously altered mudstone ; and an area of unaltered mudstone in which no ore deposits are found and an increase in size, number, and grade of ore deposits from areas of discontinuously altered to continuously altered mudstone. Discrete regional patterns of ore deposits and altered mudstone are associated with Tertiary structures; where these structures and favorable host rocks occur in juxtaposition, regional controls appear to have localized ore deposits.

From introduction: The need for fluorspar in the manufacture of open-hearth steel, hydrofluoric acid, aluminum, certain insecticides, refrigerants and airconditioning compounds, welding rods, 100-octane gasoline, and many other products necessary to the prosecution of World War II resulted in unprecedented demands for this commodity. To help increase production to meet these demands, the War Production Board in 1942 asked the United States Geological Survey to plan a comprehensive study of the fluorspar deposits in the United States. This study has been carried on in many parts of the country in cooperation with geologists and engineers of State and Federal agencies and with local producers.

From introduction: Geochemical studies of zinc-bearing peats in western New York State show them to be related genetically to underlying mineralized beds of the Lockport dolomite of Niagaran age. (...) Intermittent field work was begun in the area by the United States Geological Survey in September 1946; after some interruptions, field work was completed in June 1948. In 1950, 1,900 feet of diamond drilling was completed in the area.

From abstract: The Jarvis Creek coal field lies on the north side of the Alaska Range, between latitudes 63 35' and 63*45' N., and longitudes 145*40' and 145*50' W. It is 3 to 6 miles east of the Richardson Highway. The coal field is about 16 square miles in area, the major part of which is a rolling plateau that slopes gently northward and is bounded on the east, south. and west by bluffs facing Jarvis Creek, Ruby Creek, and the Delta River.

From abstract: The Happy Jack mine is in the White Canyon area, San Juan County, Utah. Production is from high-grade uranium deposits in the Shinarump conglomerate of Triassic age. The Shinarump strata range from 161/2 to 40 feet in thickness and the lower part of these beds fills an eastward-trending channel that is more than 750 feet wide and 10 feet deep.

From abstract: The Front Range of Colorado is composed chiefly of schists of the Idaho Springs formation of pre-Cambrian age which have been intruded by a variety of granitic batholiths. In the Crystal Mountain district the Mount Olympus granite, a satellite of Fuller's Longs Peak batholith, forms sills and essentially concordant multiple intrusions in quartz-mica schist that dips southward at moderate to steep angles. A great number of pegmatites accompanied and followed the intrusion of the sills and formed concordant and discordant bodies in schist and granite.