From Abstract: "This report describes the occurrence of the mica and its physical properties among which is an unusually wide range of colors. A table is presented showing the results of power-factor measurements made by the National Bureau of Standards on 196 samples of sheet mica from 109 mica mines and 15 feldspar mines.It is concluded that more systematic planning of mica mining, for the district as a whole. would result in an average yearly production of at least 90,000 pounds of relatively clear sheet and possibly much more."

From introduction: An autunite deposit in the SW 1/4 sec. 25, T. 10 N., R. 13 W. San Bernardino meridian, was visited by F. M. Chace on May 6 and 15, 1950. The deposit is about 100 yards west of a north-south country road and is at an altitude of approximately 2,775 feet. The autunite-bearing tuffaceous sandstone strikes N. 35-40 W. and dips 20 -25 SW. It has been traced about 40 feet along the strike at the base of the outcrop and for about 20 feet up the dip. Insufficient work was done to give an accurate idea of the size of the deposit or to determine if other autunite-bearing beds are present.

From Introduction: The field work that furnished the basis for this report was begun in 1930 and was continued at intervals until 1934. The anticlinal character of the Kettleman Hills is apparent to even the casual observer, but the many structural complications due to an intricate network of minor faults, at least in North Dome and Middle Dome, are much less obvious. Though it is improbable that these faults have any relation to the occurrence of oil, an attempt was made to map them, not only to represent the structure adequately but also because the stratigraphy could not be understood if they were neglected. Faunal zones were particularly useful in mapping. On the other hand, some lithologic units proved to be more persistent than had been expected. The two sets of features-fossils and lithology-served as checks on each other.

Introduction: Part 2 of the Systematic Report continues and concludes the study of the Mollusca from the Miocene and lower Pliocene of Virginia and North Carolina. One hundred and nineteen species, only a fraction of the known fauna, are reviewed and 66 additional species are described and figured. (See faunal chart, pp. 180-183.) The report upon the gastropods suffers from the same shortcomings obvious in the work on the pelecypods. Most of the material is from old collections made before the importance of the exact placing of the fossil locality both areally and vertically was recognized. Many of the citations of outcrops are vague and the sections generalized. Detailed field studies, particularly on the zoning of the Yorktown formation in southern Virginia and northern North Carolina, were begun later by Wendell P. Mansfield, but he died in the summer of 1939 before the completion of the work.

Abstract: A brief sketch of the stratigraphy of the Miocene of Virginia and the Miocene and Pliocene of North Carolina was prepared by Dr. W. C. Mansfield before his death in July 1939. His purpose was "to provide a background of formational nomenclature" for the taxonomic treatment of the molluscan faunas. The physical nature and distribution of the upper Tertiary formations within those States are discussed, characteristic sections given, and diagnostic molluscan species listed. Part 1 of the systematic report covers the Pelecypoda. A monographic treatment is not attempted, but 132 previously known species are considered, and 62 new species and subspecies are described and figured.

From abstract: This report presents an analysis of the statistical records of the Geological Survey regarding the production of lode gold from the Territory of Alaska for the period 1882 to 1937, inclusive. During that time lode gold to the value of $172,368,000 had been mined. The history of the discovery of lode gold and the early developments in lode-gold mining in each of the various districts is outlined briefly, and the production of lode gold in each of the geographic subdivisions is tabulated fully for each year, as far as the records and the practices of the Geological Survey permit.

Abstract: In the accompanying report reference is made to all of the deposits in Alaska in which molybdenum minerals have been definitely recognized and reported. None of the deposits have been mined commercially, and none of them have been prospected thoroughly enough to afford quantitative estimates as to their tenor and potential reserves ; in fact, at only a few of the localities has there been more than surficial testing. Forty-one separate and distinct localities where molybdenum minerals occur are listed, and the available information on factors of geologic significance regarding each occurrence is given. A small-scale map of Alaska on which the various localities are indicated forms part of the bulletin, and in the text are extensive references to the various published reports and records of the Survey upon which the statements are based. In spite of the widespread distribution of molybdenum mineralization in Alaska, the remoteness of many of the localities, their handicap through dearth of transportation facilities and labor supplies, and the already wellsupplied condition of the American market for molybdenum ores discourage the early development of any of the known deposits or search for them in unsurveyed areas. These draw-backs will doubtless become -less important factors …

This report is part of a series describing the structural features, the character of the oil- and gas-producing beds, and the localities where additional oil and gas may be found in parts of Osage County, Oklahoma. This part provides an overview of the discussions in the previous 10 publications and provides a summary of relevant information.

From abstract: Tin-bearing veinlets are exposed in a small area near Izenhood Ranch, 22 miles north of Battle Mountain, Nev. They occur in thick rhyolitic flows of Miocene (?) age, and wood tin, found in the gravels of arroyos that head in the surrounding rhyolite, presumably comes from -other veinlets not yet discovered. The exposed veinlets are about 20 feet in maximum length and a quarter of an inch in average thickness. Parallel and reticulating veinlets form lodes 4 to 6 feet thick and 15 or 20 feet long. Virtually no cassiterite is disseminated in the wall rock.

From abstract: Perry and Lewis Counties, east of the Tennessee River, in west-middle Tennessee, are underlain by nearly flat-lying rocks of Paleozoic age, with Mississippian cherty limestones forming the greater part of the surface of the western Highland Rim Plateau ridges. Near the summits of the ridges there is a fairly definite horizon in the chert that contains manganese and iron oxides in varying degrees of concentration. Weathering of the mineralized chert has produced widespread float on the hill slopes and in the beds of small spring branches, and the presence of this float, some of it rich enough for metallurgical manganese ore, has encouraged a search for promising deposits in place. In the present study 52 localities where the mineralized beds crop out or have been prospected were examined.

Abstract: This report summarizes the results of reconnaissance study of quicksilver deposits in the northwestern corner of Nevada, the northeastern corner of California, and Lake County, Oreg. made in August 1940. The Lene Pine district, Nevada, the Silvertown and Red Hawk properties in California, and the Currier and Glass Butte properties in Oregon were included. The first two of these require further development before a definite opinion as to their value can be formed. The Red Hawk mine has yielded high-grade ore, but the ore bodies so far worked are very small and scattered. The small amount of development at the recently opened Currier mine has yielded encouraging results. The deposits in the Glass Buttes are large but of such low grade that thorough sampling would be needed to determine their value. In general the region appears to warrant more attention from quicksilver prospectors than it has yet received.

From abstract: Mica has been mined in New Hampshire since 1803. Production from 1908 through 1939 has aggregated 13,326,990 pounds of sheet and punch mica, an annual average of 416,470 pounds. Since 1931 production has been below this average, because of economic conditions rather than depletions. The mica-bearing pegmatites of the Grafton and Keene districts occur mostly in sillimanite-mica schist adjacent to large areas of biotite gneiss. The pegmatite bodies range from a fraction of an inch to more than 200 feet in thickness; most of them are crosscutting, and about 75 percent strike northeast. Mica occurs sporadically in most of them but where present in commercial quantities it is localized in one or more of the following zones: (1) In quartz-plagioclase-muscovite zones 2 to 10 feet from the walls of large pegmatite bodies, (2) in or near quartz masses that occur mostly near the centers of the bodies, (3) in thin dikes 5 to 15 feet thick or in similar offshoots from larger bodies, (4) within large pegmatite bodies, in more or less tabular streaks or zones composed principally of plagioclase, quartz, and muscovite.

Abstract: The Portage Pass area is in south-central Alaska, and includes part of the narrow neck of land that joins the Kenai Peninsula with the mainland to the north. This region is in general mountainous, elevations ranging from sea level to more than 4,000 feet on the peaks bordering the area. Several glaciers, all of which are apparently receding, extend into the area. Vegetation, chiefly alder and cottonwood on the valley lowlands and some spruce and hemlock on the lower slopes, extends to an elevation of about 1,000 feet, above which the slopes are bare except for occasional clumps of brush. The bedrock of the entire area is slate, argillite, and graywacke, apparently part of the same great series that extends from the Kenai Peninsula into the Prince William Sound region and is at least in part of Cretaceous age. The only igneous rocks recognized in the area are a few acidic dikes and a small diabase dike. Small, irregular quartz veinlets are widespread. The structure is not only complex but, owing to extensive metamorphism, is in many places obscure. A general northeast strike and steep to vertical dips of both bedding and cleavage planes are the rule, but there …

Summary: In May and June 1936 Dr. C. S. Piggot of the Geophysical Laboratory, Carnegie Institution of Washington, took a series of 11 deep-sea cores in the North Atlantic Ocean between the Newfoundland banks and the banks off the Irish coast.

Preface: The author of this paper gives a thorough description of a complex of very unusual igneous rocks and associated hydrothermal deposits.

From foreword: This report on the subsurface geology of Osage County, Okla., describes the structural features, the character of the oil- and gas-producing beds, and the localities where additional oil and gas may be found. It embodies a part of the results of a subsurface geologic investigation of the Osage Indian Reservation, which coincides in area with Osage County.

From introduction: This bulletin, which is published in two parts, contains the complete results of all spirit leveling done in South Carolina by the Geological Survey of the United States Department of the Interior, including those heretofore published.' The 34th parallel of latitude, passing through Columbia, serves to divide the State into two sections, each of which is represented by one of the parts of the bulletin. Part 1 deals with the section lying north of the 34th parallel, designated as northern South Carolina, and part 2 deals with the section lying south of that parallel, designated as southern South Carolina. In each part descriptions of the points for which figures of elevation have been determined are listed according to the quadrangles in which the points occur, and the quadrangles are arranged in alphabetic order.

From introduction: This report details the results of a geological survey of the Libby Quadrangle, Montana.

Abstract: The manganese deposits of the Paymaster district, in Imperial County, Calif., extend along steeply inclined normal fault fissures which cut Tertiary (?) volcanic breccia and fanglomerate. The ore deposits are in part open-space fillings composed largely of psilomelane, and in part fault breccia replaced by psilomelane, pyrolusite, and manganite. Calcite and rock fragments are the chief impurities. High-grade ore now exposed averages about 40 percent manganese, and contains much barium. About 3,000 tons of ore averaging 42 percent manganese was produced from the district by hand-sorting in 1917-18. It is estimated that nearly the same amount could be produced again, largely from present workings. In addition, a few tens of thousands of tons of milling ore, estimated to contain between 10 and 30 percent of manganese, are believed to exist in veins one to three feet wide within one or two hundred feet of the surface.

Abstract: Based on the records of several hundred deep wells, contour maps have been prepared showing the monoclinal structure of part of western New York, and isopach lines have been drawn showing the westward convergence of the rocks. The mode of occurrence of natural gas in the Medina group is briefly discussed. The location of the gas fields has not been determined by structural traps, but rather stratigraphy and lithology are the controlling factors in trapping the gas, which occurs in porous lenses and streaks of sandstone sealed within impermeable beds. This mode of occurrences of the Medina gas makes the search for new fields in western New York more hazardous than in most natural gas regions. As structure has not formed traps for the gas there is no surface guide to favorable sites for testing, and new fields are found by haphazard drilling. It would be helpful, however, when wells are sunk, to study the lithology of the gas-bearing zone by an examination of the drill cuttings and core samples of the sand and to have electrical logs made of the wells to obtain measurements of permeability and porosity. Such tests may indicate the direction of greatest porosity in …

From introduction: The sampling on which the estimates of ore reserves in this report are partly based was done by Lasky and Roberts. The text was written by Lasky, who, except where otherwise noted, is responsible for any descriptions, comments, and conclusions concerning the area beyond the limits of the Hanna holdings, as well as for all statements concerning reserves and recommendations for future prospecting.

From abstract: The Santa Clara coal district is 7 to 10 kilometers west of Tonichi, a small town on the Rio Yaqui, in southeastern Sonora, Mexico. Tonichi was the terminus of a branch railroad from Corral until May 1945, when the end of the line was removed. The coal deposits were developed by the Southern Pacific Railroad from the 1890's until about 1911, when the mines were abandoned, partly because the coal was found unsuitable for use in locomotives. Other coal deposits, near Los Bronces and San Javier, west of the Santa Clara district, were mined for a number of years to provide coal for a silver smelter at San Javier which was abandoned sometime during the 1920's. Since 1942 the Santa Clara deposits have been reopened; through 1945 about 50,000 tons of coal had been shipped, at first to the Boleo copper smelter at Santa Rosalia, Baja California, and more recently to Guadalajara, Jalisco, for the manufacture of calcium carbide.

From introduction: This is one of a series of detailed studies of the antimony deposits of Mexico, which were investigated by the United States Geological Survey and the Instituto de Geologia de Mexico. The investigation was part of a cooperative program sponsored by the Interdepartmental Committee for Scientific and Cultural Cooperation, under the auspices of the Department of State.

From abstract: On the west coast of Chichagof Island, southeastern Alaska, are three nickel-copper deposits that consist of norite containing the sulfide minerals pyrrhotite, pentlandite, and chalcopyrite. The deposits are within less than a mile of each other and are, by water, 160 miles southwest of Juneau and 70 miles northwest of Sitka. The norite is part of a stock, about 5 square miles of which is above sea level. Other rocks of the stock are amphibolite, amphibolitic norite, gabbro, diorite, quartz diorite, monzonite, granite, pegmatites, quartz veins, and schist inclusions. The stock is intrusive into a Lower Cretaceous (?) graywacke formation and an Upper Triassic (?) greenstone formation, both of which are now metamorphosed to schist.