Abstract: The fluorspar deposits near Meyers Cove, Lemhi County, Idaho, are localized along three groups of shear zones: one group strikes northeast and dips steeply northwestward, another strikes northeast and dips gently northwestward, and the third strikes northwest and dips gently southwestward. The country rocks are tuffs and flows of the Casto volcanics of Permian(?) age and the Challis volcanics of late Oligocene or early Miocene age. The known deposits are in a belt about 3 miles long and 2 miles wide and crop out at altitudes between 5,100 feet and 7,200 feet above sea level. The principal vein minerals are fluorite, chalcedony, and barite. The fluorite occurs as lodes, crusts around fragments of rock, and replacements of fine breccia. The lodes range in size from veinlets to vein zones several hundred feet long and as much as 20 feet wide and contain ore that ranges in grade from 40 percent to 85 percent CaF2; the average grade is about 50 percent CaF2.

From Abstract: Niobium (columbium) and titanium occur in several minerals and rocks of the Magnet Cove and Potash Sulphur Springs areas. Niobium is in demand for use in high-temperature and noncreep steels; titanium metal is becoming an important structural material. The Magnet Cove and Potash Sulphur Springs areas are in central Arkansas between the communities of Malvern and Hot Springs. They are underlain by similar alkalic igneous complexes consisting of nepheline syenite, more basic alkalic rocks, and calcite rock or carbonatite. The igneous rocks transect sedimentary rocks of Paleozoic age and were truncated by erosion of Late Cretaceous age.

From abstract: The chromite deposits of the central part of the Stillwater complex lie in a belt 9 miles long between the valleys of Boulder River and the West Fork of the Stillwater River in Sweet Grass County, Mont. The chromite occurs as layers near the middle part of the ultramafic zone in the lower part of the complex. The layers, originally horizontal, have been tilted so that they dip northeastwards at angles ranging from nearly horizontal to nearly vertical, and are cut by many cross faults, the largest with a horizontal offset of 3,000 feet. Investigations by the United States Geological Survey and the United States Bureau of Mines have shown that in this belt there are 5 sections ranging in length from 850 to 3,800 feet along the strike where the continuity and grade of the chromite can be reasonably inferred.

This report follows the geological field studies of dolomite deposits near Marble Stevens county, Washington.

From abstract: The mapped area of the Henryetta mining district includes about 168 square miles in Okmulgee County in the east-central part of Oklahoma. The rocks in this district consist of sandstone, silty shale, and shale, and are divided into the Senora formation and the overlying Calvin sandstone of Pennsylvanian age.

This report studies the geology of mineral deposits in Mount Harris, Pilot Knob, Elkhead Creek, and Daton Peek quadrangles in northwestern Colorado.

This report follows the geological study of the Crazy Woman Creek area in Johnson County, Wyoming where oil, gas, and coal investigations were made.

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: The High Climb pegmatite, Custer County. S. Dak., belongs to the series of pegmatitic and granitic rocks that characterize the Harney Peak region of the southern Black Hills. It intrudes pre-CamInbriani metamorphic rocks consisting chiefly of quartz-mica schist. Along part of the pegmatite contact the country rock has been altered to a tourmaline-rich schist.

This report investigates the physical stratigraphy of the Permian Phosphoria formation of the central and northern Rocky Mountains.

From abstract: Slope and Bowman Counties, N. Dak., include an area of about 2,450 square miles in the southeastern part of the Fort Union coal region of North Dakota, South Dakota, and Montana. In anticipation of a future increase in the demand for the low-rank coal of this region as a fuel for electric power plants and as a raw material for various chemical synthesizing processes, Slope and Bowman Counties were investigated for deposits of lignite that could be mined by large scale strip mining methods. All the lignite beds of economic importance in this area are in the Fort Union formation, particularly in the Tongue River member. The beds are nearly horizontal, dipping about 25 to 50 feet per mile north and northeast from the Cedar Creek anticline in the southwest corner of the area.

The following report was prepared in cooperation with the Colorado State Geological Survey Board and the Colorado Metal Mining Fund Board. This report concerns work done partly on behalf of the U.S. Atomic Energy Commission and is published with the permission of the Commission.

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 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: The Murray area includes almost the whole drainage basins of Prichard, Eagle, and Beaver Creeks and is underlain by the pre-Cambrian Belt series which is subdivided, from oldest to youngest, as follows: Prichard formation (upper and lower parts), Burke formation, Revett quartzite, St. Regis formation, Wallace formation, and Striped Peak formation. The Belt series in this area is cut by many small monzonite stocks believed to be related to the Cretaceous Idaho batholith. This report describes only the lead-zinc mines. The lead-zinc production around Murray reached its peak in 1911 and 1912 when the Monarch, Edith Murray (Pontiac or Terrible Edith), Bear Top, Paragon, Black Horse, and Silver Strike mines were active. Many of these mines have produced ore intermittently since then, and the Jack Waite mine has been very active since about 1930.

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 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.

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: 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: Thorium has been found since 1949 in at least 33 deposits in an area 6 miles wide and 20 miles long in the Powderhorn district, Gunnison County, Colo. The district is underlain largely by pre-Jurassic metamorphic and igneous rocks, most of which, if not all, are pre-Cambrian in age. These rocks are overlain by sandstone of the Morrison formation of Jurassic age, and by volcanic rocks of the Alboroto group and the Hinsdale formation of Miocene and of Pliocene(?) age, respectively.

From introduction: The purpose of this report is to summarize available information concerning iron-ore resources in the United States in order to provide a general background for understanding and appraising the present status of this basic commodity.

From abstract: A deposit of rare-earth minerals in the Scrub Oaks iron mine, Morris County, N. J., was mapped and sampled in 1955. The rare-earth minerals are mainly in coarse-grained magnetite ore and in pegmatite adjacent to it. Discrete bodies of rare-earth-bearing magnetite ore apparently follow the plunge of the main magnetite ore body at the north end of the mine. Radioactivity of the ore containing rare earths is about 0.2 to 0.6 milliroentgens per hour.