A report that contains the records of all the shocks observed or felt on Mount Hamilton and all those reported to the Lick Observatory by letter, as well as newspaper reports of such earthquakes.

A report about recorded shock waves observed or felt on Mount Hamilton, and all those reported to the Lick Observatory by letter, as well as newspaper reports of such earthquakes that occurred in California during that year.

A report about a complex group of mountain ridges in Northern California and Oregon. It discusses the geology of North California.

A paper which records all of the shocks observed or felt on Mount Hamilton, and all of those reported to the Lick Observatory by letter; as well as newspaper reports of such earthquakes as occurred in the state during that year.

A report about volcano response plans. It discusses a four-level color code with successive conditions. For instance, green means no risk while red means an eruption is occurring.

A report about fossils from the Chico-Téjon series of California. These fossils constitute additions to the already known molluscan fauna of an important series of rich strata.

A report about chromite deposits in the Seiad Creek and McGuffy Creek districts and the Ladd mine, Siskiyou County, California, that occur in dunite-peridotite bodies that are part of an ophiolitic sequence in the western Paleozoic and Triassic belt of the Klamath Mountains.

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 Outline of the Report: The Alleghany district, in the southern part of Sierra County, Calif., has long been famous for the high-grade gold ore of its quartz veins. The oldest rocks of the district (pp. 6-17) are of sedimentary and volcanic origin and correspond to part of the Calaveras formation as mapped in the Colfax and Downieville folios of the Geologic Atlas of the United States. These rocks are divided into five formations, of which three-the Blue Canyon, Relief, and Cape Horn formations follow the definitions laid down by Lindgren in the Colfax folio, and two-the Tightner and Kanaka formations-are new units required by the more detailed nature of the present study. It is thought possible that a conglomerate which forms the basal part of the Kanaka formation is of glacial origin. Intrusions of gabbro and more basic rocks, the latter now completely serpentinized, crop out over nearly half the area in which pre-Tertiary rocks are exposed. Small granitic dikes of later age than the basic intrusives are found in the western part of the district. Overlying and largely concealing the older rocks are auriferous gravel of Eocene and Miocene age, andesitic breccia of probable Miocen age, basalt flows …

From abstract: The Santa Monica Mountains lie only a few miles northwest of the city of Los Angeles and comprise one of the prominent structural features that adjoin the Los Angeles Basin, one of the most prolific oil-producing districts of California. Even though the eastern part of these mountains may yield no oil, information concerning the rock types, structural character, and detailed geologic history of this area should be of value to petroleum geologists. The area described in this report, which lies between Topanga Canyon on the west and the Los Angeles River on the east, presents a section of varied rock types including coarsely crystalline plutonic rocks, basic and acidic intrusive and pyroclastic rocks, metamorphic slate and schist, and a wide assortment of sedimentary rocks.

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.

This is a report on the Sunset-Midway oil field in Kern County, California, including the geology and production of oil.

The principal result of the investigations upon which this report is based is the determination within narrow limits of the preglacial depth of the Yosemite Valley and of other facts concerning its preglacial development which permit fairly definite estimates of the proportionate shares of work performed by stream and by glacier. The investigations comprise a detailed survey of the glacial and geomorphologic features of the Yosemite region and an equally intensive study of its rock formations, supplemented by reconnaissance work of both kinds in adjoining parts of the Sierra Nevada.

From abstract: Airborne radioactivity surveys in the Mojave Desert region, Kern, Riverside, and San Bernardino counties were made in five areas recommended as favorable for the occurrence of radioactive raw materials: (1) Rock Corral area, San Bernardino County. (2) Searles Station area, Kern County. (3) Soledad area, Kern County, (4) White Tank area, Riverside and San Bernardino counties. (5) Harvard Hills area, San Bernardino County. Anomalous radiation was detected in all but the Harvard Hills area.

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.

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.

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.

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.

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