Synopsis: The Lassen Peak, Volcanic Ridge, which connects the northern end of the Sierra Nevada in California with the Coast Range and separates the upper portion of the Sacramento Valley from the great interior basin, is composed chiefly of lavas from many volcanic reuptions.

Stratigraphy, structure, and economic geology of parts of Monterey, San Luis Obispo, and San Benito Counties.

From preface: This report satisfies the demand of the public for reliable information and to gather data which should be of use in planning further geologic work in Nevada.

From introduction: This report determines the geographic distribution and thickness of the bituminous shale, or oil shale, or tar shale of the Green River formation of the Uinta Basin in Colorado and Utah.

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

Introduction: In the following pages a number of selected analyses or tests of the oil and gas from this field are given, with such descriptions of the analytical methods used as are necessary to an understanding of the results.

From abstract: Bulletin W is about the deformation of the Mesozoic Franciscan Complex of the Eastern Santa Maria basin in California. Bulletin X is about the regional thermal maturity of the surface rocks of the mentioned basin as well as the Santa Barbara-Ventura basin area in California.

From introduction: This report describes the geology of the area only to the extent necessary for preliminary evaluation of the possibilities for the disposal of liquid radioactive waste by injection through deep wells. Their value will increase with development of extensive commercial production of atomic power and attendant creation of radioactive waste from the processing of spent fuel elements. The disposal of liquid waste in deep reservoirs is only one of several possibilities that must be considered.

From abstract: A complex Neogene history characterizes the offshore Santa Maria basin and the northwest margin of the western Transverse Ranges, California. This history includes the transition from subduction to a transtensional and then transpressional plate boundary, including about 900 of clockwise rotation of the western Transverse Ranges. This report uses seismic reflection data to document the geometry of structures that accommodated this deformation and offshore well data to date and correlate the sediments which were affected by the different tectonic episodes.

From introduction: This report describes the deposits of analcite in the Green River formation, to compare them with other similar deposits, and to present them with other similar deposits, and to present the observations and inferences that led him to explain them as alteration products of volcanic ash that fell into an ancient saline lake. The report also records the occurrence of several thin beds of sepiolite, or meerschaum, in the Green River formation and presents new data on the molds of saline minerals of the Green River formation whose determination affects directly the interpretation of the analcite and sepiolite deposits.

From introduction: The district discussed in this report embraces the entire northern peninsula of Michigan and the parts of northern Wisconsin and northeastern Minnesota that were covered by a re-advance of the Superior lobe of the Labrador ice sheet late in the Wisconsin stage of glaciation.

From abstract: The region described in this report includes a foothill belt of the San Emigdio and Tehachapi Mountains along the southern border of San Joaquin Valley. The belt displays portions of the rugged granitic cores of the mountains and also rocks of Eocene, Oligocene, Miocene, Pliocene, and Pleistocene age. Although there is thus a complete representation of the geologic series from the Eocene to the Pleistocene, some portions of the different series are wanting because of major faults and overlaps. The thickness of the Tertiary rocks (Eocene to Pliocene) varies considerably but has a maximum of about 29,000 feet. Miocene and Pliocene rocks cover most of the area investigated.

Abstract: Structural and petrologic studies in the Berry Creek quadrangle at the north end of the western metamorphic belt of the Sierra Nevada have yielded new information that helps in distinguishing between the chemically similar Paleozoic and Mesozoic rocks. The distinguishing features are structural and textural and result from different degrees of deformation. Most Paleozoic rocks are strongly deformed and thoroughly recrystallized. Phenocrysts in metavolcanic rocks are granulated and drawn out into lenses that have sutured outlines. In contrast, the phenocrysts in the Mesozoic metavolcanic rocks show well-preserved straight crystal faces, are only slightly or not at all granulated, and contain fewer mineral inclusions than do those in the Paleozoic rocks. The groundmass in the Paleozoic rocks is recrystallized to a fairly coarse grained albite-epidote-amphibole-chlorite rock, whereas in the Mesozoic rocks the groundmass is a very fine grained feltlike mesh with only spotty occurrence of well-recrystallized finegrained albite-epidote-chlorite-actinolite rock. Primary minerals, such as augite, are locally preserved in the Mesozoic rocks but are altered to a mixture of amphibole, chlorite, and epidote in the Paleozoic rocks. In the contact aureoles of the plutons, and within the Big Bend fault zone, which crosses the area parallel to the structural trends, all …

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: The Geysers-Clear Lake geothermal area lies within the central belt of the Franciscan assemblage in northern California. The structure of this terrane is characterized by northeast-dipping imbricate thrust slices that have been warped and cut by steeply dipping strike-slip and normal faults. Introduction of magma into the crust beneath the Geysers-Clear Lake area can be related to eastsoutheast extension accompanying northward propagation of the San Andreas transform system between the Clear Lake region and Cape Mendocino within the last 3 million years. The initiation of strike-slip faulting during this time terminated subduction of elements of the Farallon plate beneath North America as strike-slip motion was taken up along the Pacific-North American plate boundary. The mechanism for magma generation appears to require a heat source in the mantle that mixed mantle-derived melts with various crustal rocks. These crustal rocks may have included the Franciscan central and coastal belts, ophiolite, Great Valley sequence, and possibly middle and late Tertiary rocks subducted before initiation of strike-slip faulting.

From abstract: A composite section of the Silurian, Devonian, and Mississippian formations in the Funeral Mountains between Death Valley and Amargosa Valley is about 4,700 feet thick. The formations are in the top of a concordant, complexly faulted sequence that is about 25,000 feet thick from the highest part of the Precambrian to the Upper Mississippian. The Silurian and younger formations consist of marine dolomite and limestone that contain some regionally characteristic cherty and siliceous clastic beds as well as widely spaced fossiliferous zones.

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 Fort Piute Wilderness Study Area (CDCA-267) is in northeastern San Bernardino County, California, near the boundary between California and Nevada. Mineral surveys were requested for 31,371 acres of the Fort Piute Wilderness Study Area. In this report the area studied is referred to as "the study area". Examination of mines and prospects in the area was accomplished by the U.S. Bureau of Mines in 1981 and 1982. Field investigations of the area were carried out by the U.S. Geological Survey in 1983 and 1985. No mines or prospects, few mining claims, and no identified resources are located within the wilderness study area. Moderate and low potential for gold resources appears limited to outcrops of gneiss and granite exposed along the eastern side of the Piute Range. Available information indicates that there is no potential for energy resources, including oil and gas, uranium, or geothermal, in the study area.

From abstract: At the request of the U.S. Bureau of Land Management, approximately 85,100 acres of the Whipple Mountains Wilderness Study Area (CDCA-312) and 1,380 acres of the Whipple Mountains Addition Wilderness Study Area (AZ-050-010) were evaluated for identified mineral resources (known) and mineral resource potential (undiscovered). In this report, the Whipple Mountains and Whipple Mountains Addition Wilderness Study Areas are referred to as simply "the study area."

From abstract: A reconnaissance to determine the uranium content of granitic rocks in the western states was made during parts of October and November 1951. The paucity of our knowledge of the granitic rocks that are most likely to contain significant quantities of uranium has prevented all but a very general isolation of areas or types of granitic rocks for reconnaissance examination.

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 abstract: The investigation in the Rock Corral area was undertaken to determine the relationship between 1) the anomalously high radioactivity recorded during an airborne survey and 2) the distribution and mineralogic mode of occurrence of radioactive material.

From abstract: The stratigraphic nomenclature of the central Santa Monica Mountains is revised to conform with present knowledge of the age, distribution, and stratigraphic relations of about 35 bedrock units. The revision is based on 1:12,000-scale mapping of the entire stratigraphic sequence and its facies, the position and stage assignment of abundant fossils, and contact relations.

From introduction: This report presents a summary of the graptolite faunas of the Basin Ranges as known from the collections of the U.S. Geological Survey and the Departments of Geology of the University of California at Los Angeles and Utah State University. The collections were made in the period 1872-1958, but only a very small number of specimens have been described or illustrated in the 80 or so years elapsed.