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Manganese, iron, and barite deposits of the James River-Roanoke River district, Virginia

During the period 1940-1942 the United States Geological Survey made a geologic study of the manganese deposits of the James River-Roanoke River district, in the general vicinity of Lynchburg, Va. (fig. 1), as part of its program of strategic minerals investigations. This work was done by the writer and supervised by D. F. Hewett. John Rodgers and W. R. Wagner assisted during part of the project. In the course of the investigation, the geology was mapped over an area about 60 miles long and several miles wide, from Altavista on the Roanoke River northeast to Howardsville on the James River (fig. 2); and the mineral deposits-principally manganese, iron, and barite-were studied. After completion of the geologic studies, the writer participated in an exploration project conducted by the United States Bureau of Mines in the early summer of 1942 at five manganese deposits in the district. This preliminary report presents the essential information concerning the mineral deposits of the region in advance of the more comprehensive report on the geology and mineral deposits that will be published as a bulletin of the U.S. Geological Survey.

Virginia↗

Review of lignite resources of western Tennessee and the Jackson Purchase area, western Kentucky

Introduction: This review of the lignite deposits of western Tennessee and the Jackson Purchase area in western Kentucky (Fig. 1) is a preliminary report on part of the U.S. Geological Survey's National Coal Resource Assessment of the Gulf Coastal Plain Coal Province. Lignite deposits of western Kentucky and Tennessee are an extension of the Gulf Coastal Plain Coal Province (Cushing and others, 1964), and currently are not economic to mine. These deposits have not been extensively investigated or developed as an energy resource. This review includes a description of the geology of the lignite-bearing units, a discussion of the available coal quality data, and information on organic petrology. Palynological data for lignite samples collected in Kentucky and Tennessee as part of this work are presented in an Appendix.

Open-File Report↗

Information relevant to the U.S. Geological Survey assessment of the Middle Devonian Shale of the Appalachian Basin Province, 2011

The U.S. Geological Survey recently assessed the potential for natural gas resources in the Middle Devonian Marcellus Shale of the Appalachian Basin Province. The Marcellus Shale was assessed as a continuous gas accumulation using a methodology identical to that used in the assessment of shale and other continuous-type assessment units throughout the United States. This preliminary report provides some additional geologic information used in the Marcellus Shale assessment. The Appalachian Basin Province encompasses rocks of the Paleozoic passive margins, the foreland basins, and fold and thrust belts formed during several episodes in the Paleozoic. The Marcellus Shale is one of many marine shales deposited in the area that is now encompassed by the Appalachian Basin Province.

Appalachian Basin Province↗

Memorandum on the hydrology of the Johnson Creek area, Dover-Madbury, New Hampshire

Ground-water conditions in the Johnson Creek area (Dover-Madbury, N.H.) are described on pages 23-26 in "Preliminary report on the ground-water resources of part of the seacoast region of New Hampshire," by Edward Bradley, U.S. Geological Survey open-file report, 1955. A copy of those pages is attached as an appendix to this memorandum. The purpose of the present memorandum is to outline the hydrology of the Johnson Creek as now understood, with particular reference to stream-discharge characteristics and their relation to geologic and ground-water conditions.

New Hampshire↗

Terrain analysis of the lunar equatorial belt

The U. S. Geological Survey began, in November 1963, a terrain analysis of the lunar equatorial belt (10°N-10°S, 60° W15°E), on behalf of the National Aeronautics and Space Administration. The purpose of the study is to establish a quantitative classification system in terms of different degrees of relative resolvable roughness, using the best available earth based techniques, the resolution of which averages one kilometer. Those parts of the lunar surface that have the least resolvable roughness at this scale have the highest statistical probability of containing safe landing areas at the one to ten meter scale for both manned and unmanned spacecraft. This preliminary report is based on eight months work prior to July 1, 1964: an unreviewed manuscript was submitted initially to the National Aeronautics and Space Administration on July 27, 1964. The report does not include any data derived from Ranger VII, and manuscript review subsequent to Ranger VII has not revealed the need for any significant changes in the conclusions. The major results are: 1) a quantitative terrain classification of the equatorial belt, chiefly in the form of a map (Plate 1), but including slope frequency distribution curves for each unit; 2) four larger scale maps (1:1, 000, 000) of the central part of the belt showing the areal distribution pattern of approximately 30, 000 individual slope measurements; 3) a large scale terrain map of the Flamsteed area, studied visually at the Lick 36" refractor, to determine the relative surface roughness below the limit of photographic resolution: 4) a full discussion of all the major techniques employed in the study, i.e. photometric slope measurement, slope measurement by shadow variation high resolution photography, and visual study techniques; 5) an extrapolation of derived roughness information below the of photographic resolution. The extrapolation is based primarily on the behavior of the lunar slope data through a wide range of resolution and on information derived from studies of different terrestrial areas at varying degrees of resolution.

Open-File Report↗

Plant and miscellaneous microfossils of the Pierre Shale

This preliminary report summarizes part of a Survey program to study, in detail, the stratigraphy and paleontology of a nearly complete sequence of Pierre Shale near Redbird, Wyoming. The physical stratigraphy and correlations are being analyzed by James Gill and W. A. Cobban. Various groups of invertebrate fossils are under study by Mr. Cobban, N. F. Sohl, and James Mello. Plant microfossils are the responsibility of Estella Leopold, assisted by Bernadine Tschudy.

Open-File Report↗

Microearthquake activity in the vicinity of Wooded Island, Hanford region, Washington

The U.S. Geological Survey (U.S.G.S.) began to monitor microearthquake activity in the region of the Atomic Energy Commission's Hanford Reservation in south-central Washington in March 1969. The Division of Reactor Development and Technology (DRDT), of the Atomic Energy Commission (AEC), supported the operation of a network of 6 (later 7) short-period, high-gain seismograph stations (Figure 1) through June 1970. Then the Chemical Processing Division (CPD) of the AEC assumed support of the original 7-station network and added 9 additional stations (Figure 1). Some preliminary results from the 7-station network covering the period 23 March 1969 to 31 December 1969 were released in the U.S.G.S. open-file4report "Geologic Investigation of Faulting in the Hanford Region, Washington", by James W. Bingham, Clark J. Landquist, and Elmer H. Baltz. Preliminary reports on the results from the seismograph network for 1970 have been submitted to the AEC. This report covers a specific zone of microearthquake activity located near Wooded Island in the Columbia River, which flows along the east side of the Hanford Reservation (Figure 1). The data cover the period 23 March 1969 to 28 February 1971.

Washington↗

Preliminary catalog of pictures taken on the lunar surface during the Apollo 17 mission

This is a catalog of all pictures taken from the lunar module or the lunar surface during the Apollo 17 lunar stay with electric Hasselblad cameras on 70 mm film. Pictures taken from lunar orbit are not listed in the tabulations. The tabulations are arranged for the following specific uses: 1) given the number of a particular frame, find its location in the sequence of lunar surface activity, the station from which it was taken and the subject matter of the picture (table 3). 2-) given a particular location or activity within the sequence of lunar surface activity, find the pictures taken at that time and their subject matter (table 2). 3) Information concerning coverage with the 500 mm camera is given in figures 1 and 2. Film usage statistics are contained in table 1. 4) given a specific frame number, find the serial number of the camera with which it was taken (table 4). Returned sample information contained in the listings was compiled by various members of the Apollo Lunar Geology Investigation Team. Detailed information concerning the samples is given in "Documentation and Environments of the Apollo 17 Samples--a Preliminary Report," U.S. Geological Survey Interagency Report 71, by the Apollo Lunar GeologyInvestigation Team. The catalog was generated by correlation of individual pictures with transcripts of verbal data and notes taken by members of the Apollo Lunar Geology Investigation Team during the Apollo 17 mission. This correlation is a complex task and is still in progress. Errors in the tabulations are therefore inevitable, but it is anticipated that these will not materially affect interpretation of geologic data from the mission.

Open-File Report↗

Comparison of sediment transport formulas and computation of sediment discharges for the North Fork Toutle and Toutle rivers, near Mount St. Helens, Washington

This preliminary report presents results of computations using twelve different sediment discharge formulas along with data from two data collection sites in the Toutle River basin. Output from six bed material discharge formulas and six bedload discharge formulas was considered. The results of the computations are presented graphically for comparison purposes only. In addition to output from the formulas, the results from suspended-sediment samples and several bedload measurements using a Helley-Smith type bedload sampler are presented. No interpretation of the output is provided. (USGS)

Open-File Report↗

An interpretation of the 1997 airborne electromagnetic (AEM) survey, Fort Huachuca vicinity, Cochise County, Arizona

Executive Summary -- In March of 1997, an airborne electromagnetic (AEM) survey of the Fort Huachuca Military Reservation and immediate surrounds (location map, http://geopubs.wr.usgs.gov/open-file/of99-007-b/index.jpg) was conducted. This survey was sponsored by the U.S. Army and contracted through the Geologic Division of the U.S. Geological Survey (USGS). Data were gathered by Geoterrex-Dighem Ltd. of Ottawa, Canada. The survey aircraft is surrounded by a coil through which a large current pulse is passed. This pulse induces currents in the Earth which are recorded by a set of three mutually perpendicular coils towed in a 'bird' about 100 m behind and below the aircraft. The bird also records the Earth's magnetic field. The system samples the Earth response to the electromagnetic pulse about every 16 m along the aircraft flight path. For this survey, the bulk of the flightpaths were spaced about 400 m apart and oriented in a northeast-southwest direction extending from bedrock over the Huachuca Mountains to bedrock over the Tombstone Hills. A preliminary report on the unprocessed data collected in the field was delivered to the U.S. Army by USGS in July 1997 (USGS Open-File Report 97?457). The final data were delivered in March, 1998 by the contractor to USGS and thence to the U.S. Army. The present report represents the final interpretive report from USGS. The objectives of the survey were to: 1) define the structure of the San Pedro basin in the Sierra Vista-Fort Huachuca-Huachuca City area, including the depth and shape of the basin, and to delineate large faults that may be active within the basin fill and therefore important in the hydrologic regime; 2) define near surface and subsurface areas that contain a large volume fraction of silt and clay in the basin fill and which both reduce the volume of available storage for water and reduce the permeability of the aquifer; and 3) to evaluate the use of the time domain electromagnetic method in the southwest desert setting as a means of mapping depth to water. Chapter one, written by M.E. Gettings, reports the results of the analysis of the aeromagnetic anomaly data. Depths to magnetic rocks computed from these data are in good agreement with depths from gravity anomaly models (Gettings and Houser, in prep.) and confirm and refine the location of the bedrock highs which reach to within 200 m of the surface in several parts of the study area. The highly faulted and generally shallow character of the basin within the study area deduced from the gravity studies is also evident in the aeromagnetic data. The caldera ring fault delimiting the buried structural southwest edge of the Tombstone caldera is expressed in the magnetic data and deeper intrusives extending outside the caldera to the southwest are inferred. Several magnetic bodies occur at shallow depths within the Precambrian granite of the Huachuca Mountains along the eastern foothills of the mountains. These are inferred to be Tertiary intrusives but remain to be confirmed by field work if any of their uppermost dikes or apotheses are exposed. Faults delineating the east-west trending bedrock high beneath the city of Sierra Vista appear to be shallow and should be investigated for surface expressions. Chapter two, written by Jeff Wynn, analyzes and interprets the conductivity depth transforms (CDTs) and provides a general evaluation of the data quality. He concludes that there is a good general correlation between the uppermost conductor seen in the CDTs and water table depth in many cases. Detailed comparisons between the ground-based vertical electric soundings (VES) and the CDTs are reported in this chapter. The two sets of data compare well in general for most sounding sites where the VES data are not noisy.

Arizona↗

An interpretation of the 1997 airborne electromagnetic (AEM) survey, Fort Huachuca vicinity, Cochise County, Arizona

In March of 1997, an airborne electromagnetic (AEM) survey of the Fort Huachuca Military Reservation and immediate surrounds was conducted. This survey was sponsored by the U.S. Army and contracted through the Geologic Division of the U.S. Geological Survey (USGS). Data were gathered by Geoterrex-Dighem Ltd. of Ottawa, Canada. The survey aircraft is surrounded by a coil through which a large current pulse is passed. This pulse induces currents in the Earth which are recorded by a set of three mutually perpendicular coils towed in a "bird" about 100 m behind and below the aircraft. The bird also records the Earth's magnetic field. The system samples the Earth response to the electromagnetic pulse about every 16 m along the aircraft flight path. For this survey, the bulk of the flightpaths were spaced about 400 m apart and oriented in a northeast-southwest direction extending from bedrock over the Huachuca Mountains to bedrock over the Tombstone Hills. A preliminary report on the unprocessed data collected in the field was delivered to the U.S. Army by USGS in July 1997 (USGS Open-File Report 97–457). The final data were delivered in March, 1998 by the contractor to USGS and thence to the U.S. Army. The present report represents the final interpretive report from USGS. The objectives of the survey were to: 1) define the structure of the San Pedro basin in the Sierra Vista-Fort Huachuca-Huachuca City area, including the depth and shape of the basin, and to delineate large faults that may be active within the basin fill and therefore important in the hydrologic regime; 2) define near surface and subsurface areas that contain a large volume fraction of silt and clay in the basin fill and which both reduce the volume of available storage for water and reduce the permeability of the aquifer; and 3) to evaluate the use of the time domain electromagnetic method in the southwest desert setting as a means of mapping depth to water.

Arizona↗

Deposits of Claiborne and Jackson age in Georgia

In 1911 the Geological Survey of Georgia published as Bulletin 26 a "Preliminary report on the geology of the Coastal Plain of Georgia," by Otto Veatch and Lloyd William Stephenson, prepared in cooperation with the United States Geological Survey under the supervision of T. Wayland Vaughan, a geologist in charge of Coastal Plain investigations, who contributed the determinations of the invertebrate fossils of the Tertiary and Quaternary formations. Although this report constituted a decided advance in our knowledge of the geology of the Coastal Plain of Georgia, it was admittedly of reconnaissance character, and corrections and additions to it were to be expected. During the last few years field work has been prosecuted vigorously in the Coastal Plain of Georgia, and the additional information thus accumulated throws light upon certain problems of stratigraphy left unsolved by Veatch and Stephenson and alters considerably some of their correlations. The object of the present paper is to present the new evidence regarding the age and correlation of the Eocene formations of Georgia and to revise in accordance with present knowledge the descriptions of the deposits of Claiborne and Jackson age.

Georgia↗

An Eocene flora from trans-Pecos Texas

During the fall of 1916 I received a small collection of fossil plants which had been obtained during a geologic reconnaissance of the trans-Pecos region of Texas, by Charles Lawrence Baker. A preliminary report was sent to Mr. Baker in November of that year and was quoted in his discussion of the geology of that region. I have since made a careful study of the collection, and although it contains only a few species the occurrence of fossil plans in this region is worthy of more definite and detailed record, especially as these plants enabled me to assign a definite age to the beginning of the igneous activity of the region and to establish correlations between the floras of the Mississippi embayment and the Rocky Mountain Region.

Professional Paper↗

Palynology of selected coal beds in the proposed Pennsylvanian System stratotype in West Virginia

The usefulness of Pennsylvanian palynomorphs, spores, and pollen grains, as an aid in coal-correlation investigations in the Appalachians, has been known for many years. However, much of this and subsequent information was scattered in the literature or was not from the proposed stratotype area of West Virginia. Investigation of coals from sections of the proposed Pennsylvanian System stratotype provided the opportunity to examine changes in palynomorph content through a number of coals from the New River Formation to the basal part of the Monongahela Formation. The rank of most coals of the Pocahontas and New River Formations of West Virginia does not permit extraction of palynomorphs with current laboratory maceration techniques. Because of this, the data of some possibly equivalent lower rank Pennsylvanian coals from adjacent parts of southern Ohio and eastern Kentucky have been included. The coals examined from the Kanawha Formation, Charleston Sandstone, and Monongahela Formations of West Virginia have yielded abundant and well-preserved palynomorphs. Attention has been focused on the Charleston Sandstone, which is a massive, complex unit lacking marine fossils and composed primarily of sandstone. The coal is a significant resource in Pennsylvanian rocks, and the correlation of coals is an important consideration in the area of the stratotype in West Virginia and in adjacent States. As a result of this preliminary examination, the approximate range zones of some important taxa have been established. These range zones together with abundance data are used to correlate the coals. The range zones of some important taxa from Lower to Upper Pennsylvanian coals are: Densosporites irregularis Hacquebard and Barss, Stenozonotriletes lycosporoides (Butterworth and Williams) Smith and Butterworth, Schulzospora rara Kosanke, Laevigatosporites spp., Radiizonates spp., Torispora securis Balme, Zosterosporites triangularis Kosanke, Thymospora pseudothiessenii (Kosanke) Wilson and Venkatachala, Schopfites dimorphus Kosanke, and Thymospora thiessenii (Kosanke) Wilson and Venkatachala. Some of the range zones are relatively short and extremely useful for correlation studies. For example, in the Charleston Sandstone, T. pseudothiessenii (Kosanke) Wilson and Venkatachala is present in the Upper No.5 Block coal (upper bench) and the No.6 Block coal, whereas Schopfites dimorphus Kosanke is restricted to the No.6 Block coal. Thymospora thiessenii (Kosanke) Wilson and Venkatachala is not restricted to the Pittsburgh No.8 coal, but it is the only coal known in which this taxon is so dominant (more than 70 percent of the palynomorph assemblage). This preliminary report has provided a framework for the correlation of a selected number of coals occurring in Ohio and eastern Kentucky with those of the proposed Pennsylvanian System stratotype of West Virginia. In other studies, additional samples from the stratotype would be examined for ultimate correlation with rocks of Pennsylvania and in adjacent States and elsewhere.

Professional Paper↗

Stratigraphic sections of the Phosphoria formation in Wyoming, 1947-48

As part of a comprehensive investigation of the phosphate deposits of the western field begun in 1947, the U. S. Geological Survey has measured and sampled the Permian Phosphoria formation at many localities in Wyoming and adjacent states. Because these data will not be fully synthesized for many years, segments of the data, accompanied by little or no interpretation, will be published as preliminary reports as they are assembled. This report, which contains abstracts of some of the sections measured in western Wyoming (pl. 1), is one of this series. The field and laboratory procedures adopted in these investigations are described rather fully in a companion report (McKelvey and others, 1952a). Many people have taken part in this investigation. R. M. Campbell, R. A. Gulbrandsen, R. A. Harris, D. M. Larrabee, F. W. O'Malley, O. A. Payne, R. S. Sears, R. P. Sheldon, and R. A. Smart participated in the description of the strata and the collection of the samples referred to in this report. D. B. Dimick, H. A. Larsen, and T. K. Rigby assisted in the preparation of exposures and the crushing and splitting of samples in the field. The laboratory preparation of samples for chemical analysis was done in Denver, Colo., under the direction of W. P. Huleatt. Most of the P 2 O 5 and acid-insoluble analyses were made for the Survey by the U. S. Bureau of Mines at the Northwest Electrodevelopment Laboratory, Albany, Oreg., under the direction of S. M. Shelton and M. L. Wright. Most of the Al 2 O 3 , Fe 2 O 3 , and loss-on-ignition analyses were made by the Trace Elements Section laboratory of the Survey in Washington, D. C., under the direction of J. C. Rabbitt by chemists I. Barlow, A. Caemmerer, J. Greene, F. S. Grimadli, N. Guttag, H. Levine, H. Mela, Jr., and R. G. Milkey, and most of the spectrographic reports were prepared in this laboratory by C. L. Waring. The samples from one locality (Coal Canyon) were analyzed for P 2 O 5 , Al 2 O 3 , Fe 2 O 3 , V 2 O 5 , F, loss on ignition, and acid insoluble in the Chemical Laboratory of the Tennessee Valley Authority at Wilson Dam, Alabama, and spectrographically by D. M. Mortimer, of the Bureau of Mines at Albany. Compilation of the data has been largely by R. P. Sheldon and F. D. Frieske under the supervision of R. W. Swanson. Organization of the tabular data has been largely by Anita Cozzetto.

Wyoming↗

Stratigraphic sections of the Phosphoria formation in Utah, 1947-48

As part of a comprehensive investigation of the phosphate deposits of the western field begun in 1947, the U. S. Geological survey has measured an sampled the full thickness of the Permian Phosphoria formation and its partial correlative, the Park City formation, at many localities in Utah and other western states. Although these data will not be fully analyzed for several years, segments of the data, accompanied by little or no interpretation, will be published as preliminary reports. This report, which contains abstracts of many of the sections measured in northeastern Utah (pl. 1), is one of this series. The field and laboratory procedures adopted in these investigations are described rather fully in a companion report (McKelvey and others, 1952). A large number of people have taken part in this investigation. J. B. Collins, R. A. Gulbrandsen, R. A. Hoppin, J. A. Noel, F. W. O'Malley, O. A. Payne, J. F. Rominger, R. P. Sheldon, J. E. Smedley, and R. G. Waring participated in the description of strata and collection of samples referred to in this report. D. B. Dimick, H. A. Larsen, and T. K. Rigby assisted in the preparation of trenches and the crushing and splitting of samples in the field. The laboratory preparation of samples for chemical analysis was done in Denver, Colo., under the direction of W. P. Huleatt. Most of the chemical analyses reported herein were made for the Survey by the U. S. Bureau of Mines at the Northwest Electrodevelopment Laboratory, Albany, Oreg., under the direction of S. M. Shelton and M. L. Wright. All the samples from one locality (Brazer Canyon) were analyzed in the Chemical Laboratory of the Tennessee Valley Authority at Wilson Dam, Ala. Some of the Al 2 O 3 , Fe 2 O 3 , and loss-on-ignition analyses were made in the Trace Elements Section laboratory of the Survey in Washington, D. C., under the direction of J. C. Rabbitt by chemists I. Barlow, A Caemmerer, J. Greene, N. Guttag, and E. H. Humphrey. The spectrographic analyses were made by D. M. Mortimer, of the Bureau of Mines in Albany. Compilation of the data has been largely by R. P. Sheldon and F. D. Frieske under the supervision of R. W. Swanson. Organization of the tabular data has been largely by Anita Cozzetto.

Utah↗

Stratigraphic sections of the Phosphoria in Montana, 1947-48

The U. S. Geological Survey has recently measured and sampled the Phosphoria formation at many localities in Montana and other western states. These data will not be fully synthesized and analyzed for several years, but segments of the data, accompanied by little or no interpretation, will be published as preliminary reports as they are assembled. This report, which contains abstracts of many of the sections measured in southwestern Montana (pl. 1), is one of this series. The field and laboratory procedures adopted in these investigations are described rather fully in a companion report (McKelvey and others, 1952). Many people have taken part in this investigation. The program of which this work is a part was organized by V. E. McKelvey. J. G. Evans, J. E. Joyce, J. A. Kelleher, R. L. Konizeski, J. A. Mann, R. L. Parker, J. E Smedley, L. A. Thomas, and W. H. Wilson participated in the description of strata and collection of samples referred to in this report. The laboratory preparation of samples for chemical analysis was done in Denver, Colo., under the direction of W. P. Huleatt. All the P 2 O 5 , F, V 2 O 5 , and acid-insoluble analyses were made for the Survey by the U. S. Bureau of Mines at the Northwest Electrodevelopment Laboratory, Albany, Oreg., under the direction of S. M. Shelton and M. L. Wright. The Al 2 O 3 , Fe 2 O 3 , and loss-on-ignition analyses were about equally distributed between the Bureau of Mines and the Trace Elements Section laboratory of the Survey in Washington, D. C., under the direction of J. C. Rabbit by chemists I. Barlow, A. Caemmerer, J. Greene, N. Guttag, and E. H. Humphrey. The spectrographic analyses were made by D. M. Mortimer, of the Bureau Mines in Albany, and the oil-shale analyses were made by the Bureau of Mines Petroleum and Oil-Shale Experiment Station at Laramie, Wyo. Compilation of the data has been largely by R. P. Sheldon and F. D. Frieske. Organization of the tabular data has been largely by Anita Cozzetto.

Montana↗

Stratigraphic sections of the Phosphoria formation in Idaho, 1947-48, Part III

.The U.S. Geological Survey has measured and sampled the Phosphoria formation at many localities in Idaho and other western states. These data will not be fully synthesized and analyzed for several years but segments of the data, accompanied by little or no interpretation, are published as preliminary reports as they are assembled. This report, which contains abstracts of many of the sections in southeastern Idaho (fig. 1), is one of this series and is the third report of data gathered in Idaho during 1947 and 1948. The field and laboratory procedures adopted in these investigations are described rather fully in a companion report (McKelvey and others, 1953). Many people have taken part in this investigation, which was organized and supervised by V. E. McKelvey. D. A. Bostwick, R. M. Campbell, R. A. Gulbrandsen, R. A. Harris, R. L. Parker, R. A. Smart, J. E. Smedley, R. H. Thurston, and R. G. Waring participated in the description of strata and collection of samples referred to in this report. D. B. Dimick, Jack George, W. S. Hunziker, J. E. Jones, H. A. Larsen, and T. K. Rigby assisted in the preparation of trenches and collection, crushing, and splitting of samples in the field. The laboratory preparation of samples for chemical analysis was done in Denver, Colo., under the direction of W. P. Huleatt.

Idaho↗