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

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

From abstract: This report describes four species of Ostreidae from the Upper Cretaceous of the Gulf region. The zones that the species characterize lie either in the upper part of the Austin chalk or in beds of upper Austin age.

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 …

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.

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 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.

From abstract: Cassiterite and spodumene, of possible economic importance, occur in a belt, 24.5 miles long and 1.8 miles in maximum width, extending southwestward from Lincolnton to Grover, N. C. This belt is in the Piedmont province, an upland with an average altitude of 1,000 feet, and is readily accessible by rail and highway. The region is underlain by crystalline limestone, quartzite, schists, gneisses, and granite. The rocks strike northeast and, in most of the belt, dip steeply northwest. Most of them are deeply weathered.

From abstract: Cassiterite was discovered along Irish Creek in the Blue Ridge in the northern part of Rockbridge County, Va., in 1846, but active prospecting and development work were not begun until 1884. The production has been small, probably less than 1,000 tons of ore, and has come chiefly from workings on Panther Run, a small tributary near the headwaters of Irish Creek.

Abstract: The Three Kids manganese district, in Clark County, Nev., has produced between 15,000 and 20,000 tons of ore, which contained between 30 and 40 percent manganese, 1.5 percent iron, and 12 percent silica. It is estimated that the reserves in the district aggregate about 5,500,000 tons of ore averaging about 10 percent manganese. Of this amount about 800,000 tons contains more than 20 percent manganese and 4,700,000 tons contains from 5 to 20 percent manganese. The manganese ore is a sedimentary deposit and consists of wad interbedded with lake or playa sediments belonging to the Muddy Creek formation of Pliocene (?) age. Where the manganese content is as high as 30 percent, the wad forms thick massive beds separated by thin almost barren partings. Where the content is low, the wad forms very thin lenses or small irregular blebs scattered through sandstone, or a cement for the sand grains. The zone of manganiferous beds ranges from about 10 to 75 feet in aggregate thickness, but at most places the thickness is between 25 and 40 feet.

Abstract: At Snipe Bay, on the outer coast of Baranof Island, about 46 miles southeast of Sitka in southeastern Alaska, is a nickelcopper deposit that consists of a mass of basic rock intruded into quartzite and quartz schist. Neither the size nor the grade of the deposit is adequately known. Natural exposures and those in a few prospect openings indicate that to an assumed depth of about 130 feet below the lowest point on the outcrop there is a reserve of about 430,000 tons of low-grade nickelbearing material, which, to judge from available assays and from comparison with similar material from other places, probably does not contain more than 0.3 percent each of nickel and copper. The deposit thus appears too small and of too low grade to permit the recovery of the nickel and copper except at a considerable financial loss; but as the location is favorable for largescale, low-cost development, further prospecting may be justified, in the hope that a moderate amount of surface stripping, plus a few diamond-drill holes, might indicate that the deposit is larger, and possibly of higher grade, than it is safe to infer from the available data.

From abstract: The Stampede Creek area lies about 120 miles southwest of Fairbanks, Alaska. It is most readily accessible by air during the summer and by tractor road during the winter. Since 1936 approximately 2,400 tons of shipping-grade antimony ore and concentrates, containing about 1,300 tons of metallic antimony, have been produced at the Stampede mine. The mine was closed down in the spring of 1941, principally because of the high cost of transportation. The area is underlain largely by metamorphosed rocks of the Birch Creek schist. The schist has been warped and crumpled into many broad, open folds which strike northeast and also plunge to the northeast. The Stampede mine is in the schistose quartzite member of the Birch Creek schist.

From abstract: The nickel-copper deposit near the north end of Admiralty Island, about 18 miles in an airline west of Juneau, in southeastern Alaska, consists of a basic sill which averages somewhat more than 100 feet in thickness. The sill, which dips eastward, is intrusive into a thick sequence of phyllite and various types of schist. The rock of the sill consists principally of the silicate minerals labradorite and olivine, but it also contains magnetite and the sulfides pyrrhotite, pentlandite, and chalcopyrite. It assays, on the average, about 0.34 percent nickel and 0.35 copper, which are doubtless mostly in the pentlandite and chalcopyrite respectively but are probably constituents of other minerals also. A significant proportion of nickel and copper is probably contained in the olivine and perhaps in the pyrrhotite.

From abstract: Deposits of vanadium-bearing sandstone are widely distributed in western Colorado and eastern Utah and have been the principal domestic source of vanadium, uranium, and radium. Except during a few years when operations were relatively small, deposits at one or more places in this region have been intensively mined since 1909. Production has increased considerably each year since 1937.

From abstract: The Coso quicksilver district, which is in the Coso Range, Inyo County, Calif., produced 231 flasks of quicksilver between 1935 and 1939. The quicksilver mineral, cinnabar, was not recognized in the district until 1929, although the hot springs near the deposits have been known since about 1875...The granitic rock on which much of the sinter rests is considerably altered. The cinnabar was deposited as films and grains in open spaces in the sinter, during one stage in a sequence of hot spring activities that still continues. The amount of sinter in the district is estimated to be about 1,800,000 tons. Although the greater part of this does not contain much cinnabar, the total quantity of such material is large enough to be of interest as a low-grade ore.

From abstract: The manganese deposits of the Artillery Mountains region lie within an area of about 25 square miles between the Artillery and Rawhide Mountains, on the west side of the Bill Williams River in west-central Arizona. The richest croppings are on the northeast side of this area, among the foothills of the Artillery Mountains. They are 6 to 10 miles from Alamo. The nearest shipping points are Congress, about 50 miles to the east, and Aguila, about 50 miles to the southeast. The principal manganese deposits are part of a sequence of alluvial fan and playa material, probably of early Pliocene age, which were laid down in a fault basin. They are overlain by later Pliocene (?) basalt flows and sediments and by Quaternary basalt and alluvium. The Pliocene (?) rocks are folded into a shallow composite syncline that occupies the valley between the Artillery and Rawhide Mountains, and the folded rocks along either side of the valley, together with the overlying Quaternary basalt, are broken by faults that have produced a group of horsts, grabens, and step-fault blocks.

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.