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Paleozoic Formations of the Mosquito Range, Colorado

Description: From introduction: From the time of the publication of the Leadville monograph 2 by the United States Geological Survey, in 1886, the general geology and stratigraphy of the Mosquito Range around the Leadville and Alma districts have been known. In the recent resurvey of the area, however, it has been found necessary to undertake much more detailed studies of most of the formations. In particular, the sediments of Pennsylvanian age and the overlying red beds have received considerable attention and thought. This study was necessary to determine the amount of displacement along some of the notable faults and the depth to older strata that had contained valuable ore deposits in the larger mining districts. In some places the outcrops appear to have been improperly correlated in the older reports. These were given additional study, and considerable revision of stratigraphic sections has been necessary.
Date: 1934
Creator: Johnson, J. Harlan
Partner: UNT Libraries Government Documents Department

A Lower Lance Florule from Harding County, South Dakota

Description: From page 127: For the last few years Mr. Henry E. Lee, of Rapid City, S.Dak., has been sending me selected material from the lower part of the Lance formation of Harding County, S.Dak., the exact locality being what is locally known as the Jump Off, an erosion basin of the headwaters of the South Fork of the Grand River, 10 miles north of the East Short Pine Hills. 1 The matrix is a soft gray friable sandstone, and consequently only the coarser, more resistant plants are preserved. In view of the coarseness of the matrix the preservation is excellent, although usually the finer details of venation are obscure. In the sands overlying the plant beds are thin seams of impure lignite.
Date: 1934
Creator: Berry, Edward Wilber
Partner: UNT Libraries Government Documents Department

Geology of the Marathon Region, Texas

Description: From abstract: This report describes the geology of the Marathon region, in trans-Pecos Texas. The Marathon region lies on the edge of the Mexican Highlands province, where that province merges into the Great Plains on the east. Structurally, the region is a broad dome of Cretaceous rocks, from whose central part the Cretaceous cover has been stripped away, leaving an area of low country in the center, the Marathon Basin. Here strongly folded Palcozoic rocks are exposed. The Monument Spring and Marathon quadrangles, described in detail in this report, extend across the basin area.
Date: 1937
Creator: King, Philip Burke
Partner: UNT Libraries Government Documents Department

Geomorphology of the North Flank of the Uinta Mountains

Description: From introduction: The geologic record of the Tertiary period in the Green River Basin of southwestern Wyoming consists, in a broad way, of two quite different parts. The history of the first part, lasting through the Eocene epoch and perhaps on into the early Oligocene, was recorded in a thick series of sedimentary rocks of fluviatile and lacustrine origin. The history of the second part was recorded chiefly by successive stages of stream planation and stream trenching, but also in part by fluviatile sedimentation and, in certain localities, by glacial deposits. The first part of the record is virtually continuous, though its interpretation is by no means simple and obvious. The second part of the record is distinctly fragmentary, and the evidence the fragments provide is difficult to evaluate and to integrate.
Date: 1936
Creator: Bradley, Wilmot H.
Partner: UNT Libraries Government Documents Department

The Recognizable Species of the Green River Flora

Description: Abstract: The identification of new collections of fossil plants from the Green River formation of middle Eocene age made it necessary to reexamine the megascopic types of the Green River flora. This study resulted in the reassignment of some species and the rejection of such species as were based on fragmentary, indefinable specimens. The recent collections yielded 22 new species. Exclusive of the microscopic forms of thallophytes and pollens, the flora now numbers 135 megascopic species that are considered to be recognizable and distinctive. The new elements found in the flora do not alter the previously expressed opinion that the megascopic Green River flora lived in a warm-temperate well-watered environment.
Date: 1934
Creator: Brown, Roland W.
Partner: UNT Libraries Government Documents Department

Miocene Plants from Idaho

Description: Abstract: The author describes 75 species of plants from the Miocene of about 30 localities in Idaho. These plants represent 40 genera in 28 families and 17 orders, and the most common types are species of Acer, Quercus, Populus, Betula, and Laurus. There are 2 ferns, 3 monocotyledons, and 70 dicotyledons, 18 of which are no longer present in the northwestern United States. There are some xerophytic types, but the majority are mesophytic, possibly indicating a mixture from different altitudes. The beds are correlated with the Latah formation and considered to be of upper Miocene age.
Date: 1934
Creator: Berry, Edward Wilber
Partner: UNT Libraries Government Documents Department

Halloysite and Allophane

Description: From abstract: This paper is a continuation of the study of the kaolin minerals, in the first part of which, published in 1931, the kaolin minerals kaolinite, dickite, and nacrite were described. In that paper the application of chemical, optical, X-ray, and dehydration methods to the investigation of clay materials were discussed. The present study shows that halloysite is a fourth mineral of the kaolin group, closely related to but distinct from kaolinite. The chemical, optical, X-ray, and dehydration properties of a representative group of halloysites are recorded, all these being new data determined by the authors on separate portions of single samples whose purity has been carefully tested.
Date: 1934
Creator: Ross, Clarence S. & Kerr, Paul F.
Partner: UNT Libraries Government Documents Department

A Flora of Pottsville Age from the Mosquito Range, Colorado

Description: From introduction: This paper describes a small fossil flora from the vicinity of Leadville, central Colorado. The beds from which the flora was collected have long been referred to as the "Weber formation ", though with considerable doubt on the part of many geologists that all the beds so named in Colorado are correlative with the Weber quartzite of northeastern Utah. In current usage these Colorado beds are designated the " Weber (?) formation."
Date: 1934
Creator: Read, Charles B
Partner: UNT Libraries Government Documents Department

Studies on the Alkalinity of Some Silicate Minerals

Description: Abstract: By grinding minerals under water it has been found that they yield relative and reproducible measurements of the hydrogenion concentration resulting from their hydrolysis. Many silicate minerals and two glasses have been studied in this way by a colorimetric method of determining hydrogen-ion concentration, and some of them have been studied more quantitatively by means of the hydrogen electrode. The results of these tests are a rough index of the weathering qualities of different silicate minerals. The effect of silicate minerals on underground waters and upon geochemical changes is discussed.
Date: 1934
Creator: Stevens, R. E.
Partner: UNT Libraries Government Documents Department

The Flora of the New Albany Shale: Part 1. Diichnia Kentuckiensis, a New Representative of the Calamopityeae

Description: Abstract: A new genus of the Cycadofilicales, Diichnia, is described from the New Albany shale, of late Devonian age, in central Kentucky. The one known species, which is based on stem material showing internal structure, belongs in the family Calamopityeae. Foundation for the generic segregation is seen in the double leaf truce of the genotype, D. kentuckiensis, in contrast with the originally single trace in other known representatives of the family.
Date: 1936
Creator: Read, Charles B.
Partner: UNT Libraries Government Documents Department

Pre-Cambrian Rocks of the Lake Superior Region: A Review of Newly Discovered Geologic Features, with a Revised Geologic Map

Description: From abstract: Detailed knowledge of the geology of the pre-Cambrian rocks of the Lake Superior region has been greatly augmented since the publication of Monograph 52 by the United States Geological Survey in 1911. The authors have attempted in the present report to assemble as much of this new information as possible, and to give the reader a birdseye view of the geology as seen in the light of all studies made there up to the present time. Detailed descriptions are not presented, and the emphasis is placed upon the major problems of correlation. A revised map of the region, with cross sections, accompanies the report, bringing up to date a knowledge of the areal geology of the region, which otherwise could be gained only by consulting some 150 maps contained in almost as many separate local reports, many of which are unpublished.
Date: 1935
Creator: Leith, C. K.; Lund, Richard Jacob & Leith, Andrew
Partner: UNT Libraries Government Documents Department

The Significance of Geologic Conditions in Naval Petroleum Reserves No. 3, Wyoming

Description: From Introduction: The work on which this report is based consisted of detailed field and office studies which occupied the greater part of the summer of 1927. During this period mapping was done with plane table and telescopic alidade on a scale of 1 inch to 1,000 feet, and wells, faults, and outcrops within the productive part of the Teapot field were located in detail.
Date: 1931
Creator: Thom, W. T., Jr. & Spieker, Edmund M.
Partner: UNT Libraries Government Documents Department

Geologic History of the Yosemite Valley

Description: 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.
Date: 1930
Creator: Matthes, Franc╠žois E.
Partner: UNT Libraries Government Documents Department

Geologic History of the Yosemite Valley

Description: 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.
Date: 1930
Creator: Matthes, Franc╠žois E.
Partner: UNT Libraries Government Documents Department

Gold Quartz Veins of the Alleghany District, California

Description: 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 of probable Pleistocene age, and minor amounts of Pleistocene and Recent gravel.
Date: 1932
Creator: Ferguson, Henry G. & Gannett, Roger W.
Partner: UNT Libraries Government Documents Department

Miocene Foraminifera of the Coastal Plain of the Eastern United States

Description: From introduction: In the following report the species of Foraminifera found in the Miocene of the Coastal Plain region of the eastern United States from Florida to Maryland are described and recorded. Numerous papers have been published on this region, some of which, however, are largely lists. Where the original material on which a paper was based has not been available for the present study, the records have been omitted, as it is very difficult to place the species in their proper position without seeing the actual specimens.
Date: 1933
Creator: Cushman, Joseph A. & Cahill, Edgar D.
Partner: UNT Libraries Government Documents Department

Origin of the Anhydrite Cap Rock of American Salt Domes

Description: From abstract: The thesis of this paper is that the anhydrite cap rock of salt domes originated by the residual accumulation and consolidation, on top of a salt stock, of sedimentary anhydrite freed from the salt by solution of the top of the stock. This hypothesis is compared with that of origin from a bed of sedimentary anhydrite supposed to have overlain the salt of the salt stock in depth and to have been forced up on top of the stock as it rose. The strongest basis for the hypothesis of residual accumulation is the presence, between the anhydrite cap rock and the top of the salt stock on many salt domes, of a flat solution surface, the "salt table," decapitating anhydrite-bearing folds in the salt. The paper considers other general geologic evidence and internal petrographic evidence with a view to ascertaining to what extent they confirm or at least fit this interpretation.
Date: 1933
Creator: Goldman, Marcus I.
Partner: UNT Libraries Government Documents Department

Lithologic Studies of Fine-Grained Upper Cretaceous Sedimentary Rocks of the Black Hills Region

Description: More than nine-tenths of the Upper Cretaceous rocks in northeastern Wyoming are fine-grained shales, mudstones, and calcareous marls. A comparative study of the mineralogy, chemical and mechanical composition, density and porosity, fissility, and lamination of samples of these rocks discloses several relations that throw light on the geologic history and structural deformation of the region, and perhaps on its oil and gas possibilities.
Date: 1930
Creator: Rubey, William Walden
Partner: UNT Libraries Government Documents Department

Geology of the Eastern Part of the Santa Monica Mountains, Los Angeles County, California

Description: 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.
Date: 1930
Creator: Hoots, H. W.
Partner: UNT Libraries Government Documents Department

Geology of the Big Snowy Mountains, Montana

Description: From introduction: The main purpose of the field investigations on which this paper is based was to determine the structure of the mountains. The geologic formations were therefore studied, and sufficient data were obtained to construct a combined areal and structural map.
Date: 1931
Creator: Reeves, Frank
Partner: UNT Libraries Government Documents Department