From introduction: The study of the Crystal Mountain district, Larimer County, Colo., is but one phase of this post-World War II pegmatite program, in part carried out by the Geological Survey on behalf of the Division of Raw Materials of the Atomic Energy Commission.

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.

This report describes the stratigraphy of Pleistocene and Recent deposits in the Denver area, Colorado that was conducted intermittently between 1948-52.

The following report presents a preliminary account of the geology and economic aspects of the uranium deposits in the Eureka Gulch area.

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.

A report about stratigraphic studies of late Quaternary deposits in the Rocky Mountain region which reveal a widespread uncomformity separating deposits that differ lithologically. The deposits overlying the unconformity contain modern fauna that do not occur in older deposits.

A report about the economic geology of four mines located in the Helvetia mining district in the Santa Rita Mountains in south central Arizona. The sedimentary rocks in Helvetia range from Cambrain to Cretaceous.

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.

A report about minerals fuels and geologies located in parts of the Routt and Moffat counties, Colorado.

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

A report about the geology of the the Crazy Woman Creek area in Wyoming. Rocks of every system except the Silurian and Devonian are present in the area.

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: Radioactive material in apparently significant amounts was recognized in heavy-mineral concentrates from the gravels of four streams that head in Ear Mountain, Alaska, when collections of the United States Geological Survey were examined for radioactivity in the winter of 1944-45. This area, on the north side of the Seward Peninsula, attracted attention in 1901-02 when cassiterite was discovered in the streams. Subsequent attempts were made to develop copper- and tin-bearing lode deposits.

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.

A report about the Sugar Loaf and St. Kevin mining districts located in Colorado. Most of the bedrock consists of pre-Cambian schist, gneiss, granite, and pegmatite.

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.

This report analyzes surficial deposits in the Louisville quadrangle, Colorado, that are divided into three main groups--pre-Wisconsin, Wisconsin, and Recent.

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.

A report about phosphates found in the Permian Phosphoria formation of the Rocky Mountains. This area constitutes one of the worlds largest reserves of phosphate.