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At least 829 records · Page 46Linked to original sources
USGS2017

Groundwater-quality data in 12 GAMA study units: Results from the 2006–10 initial sampling period and the 2008–13 trend sampling period, California GAMA Priority Basin Project

The Priority Basin Project (PBP) of the Groundwater Ambient Monitoring and Assessment (GAMA) program was developed in response to the Groundwater Quality Monitoring Act of 2001 and is being conducted by the U.S. Geological Survey in cooperation with the California State Water Resources Control Board. From 2004 through 2012, the GAMA-PBP collected samples and assessed the quality of groundwater resources that supply public drinking water in 35 study units across the State. Selected sites in each study unit were sampled again approximately 3 years after initial sampling as part of an assessment of temporal trends in water quality by the GAMA-PBP. Twelve of the study units, initially sampled during 2006–11 (initial sampling period) and sampled a second time during 2008–13 (trend sampling period) to assess temporal trends, are the subject of this report. The initial sampling was designed to provide a spatially unbiased assessment of the quality of untreated groundwater used for public water supplies in the 12 study units. In these study units, 550 sampling sites were selected by using a spatially distributed, randomized, grid-based method to provide spatially unbiased representation of the areas assessed (grid sites, also called “status sites”). After the initial sampling period, 76 of the previously sampled status sites (approximately 10 percent in each study unit) were randomly selected for trend sampling (“trend sites”). The 12 study units sampled both during the initial sampling and during the trend sampling period were distributed among 6 hydrogeologic provinces: Coastal (Northern and Southern), Transverse Ranges and Selected Peninsular Ranges, Klamath, Modoc Plateau and Cascades, and Sierra Nevada Hydrogeologic Provinces. For the purposes of this trend report, the six hydrogeologic provinces were grouped into two hydrogeologic regions based on location: Coastal and Mountain. The groundwater samples were analyzed for a number of synthetic organic constituents (volatile organic compounds, pesticides, and pesticide degradates), constituents of special interest (perchlorate and 1,2,3-trichloropropane), and natural inorganic constituents (nutrients, major and minor ions, and trace elements). Isotopic tracers (tritium, carbon-14, and stable isotopes of hydrogen and oxygen in water) also were measured to help identify processes affecting groundwater quality and the sources and ages of the sampled groundwater. More than 200 constituents and water-quality indicators were measured during the trend sampling period. Quality-control samples (blanks, replicates, matrix-spikes, and surrogate compounds) were collected at about one-third of the trend sites, and the results for these samples were used to evaluate the quality of the data for the groundwater samples. On the basis of detections in laboratory and field blank samples collected by GAMA-PBP study units, including the 12 study units presented here, reporting levels for some groundwater results were adjusted in this report. Differences between replicate samples were mostly within acceptable ranges, indicating low variability in analytical results. Matrix-spike recoveries were largely within the acceptable range (70 to 130 percent). This study did not attempt to evaluate the quality of water delivered to consumers. After withdrawal, groundwater used for drinking water typically is treated, disinfected, and blended with other waters to achieve acceptable water quality. The comparison benchmarks used in this report apply to treated water that is served to the consumer, not to untreated groundwater. To provide some context for the results, however, concentrations of constituents measured in these groundwater samples were compared with benchmarks established by the U.S. Environmental Protection Agency and the State of California. Comparisons between data collected for this study and benchmarks for drinking water are for illustrative purposes only and are not indicative of compliance or non-compliance with those benchmarks. Most organic constituents that were detected in groundwater samples from the trend sites were found at concentrations less than health-based benchmarks. One volatile organic compound—perchloroethene—was detected at a concentration greater than the health-based benchmark in samples from one trend site during the initial and trend sampling periods. Chloroform was detected in at least 10 percent of the samples at trend sites in both sampling periods. Methyl tert -butyl ether was detected in samples from more than 10 percent of the trend sites during the initial sampling period. No pesticide or pesticide degradate was detected in greater than 10 percent of the samples from trend sites or at concentrations greater than their health-based benchmarks during either sampling period. Nutrients were not detected at concentrations greater than their health-based benchmarks during either sampling period. Most detections of major ions and trace elements in samples from trend sites were less than health-based benchmarks during both sampling periods. Arsenic and boron each were detected at concentrations greater than the health-based benchmark in samples from four trend sites during the initial and trend sampling periods. Molybdenum was detected in samples from four trend sites at concentrations greater than the health-based benchmark during both sampling periods. Samples from two of these trend sites had similar molybdenum concentrations, and two had substantially different concentrations during the initial and trend sampling periods. Uranium was detected at a concentration greater than the health-based benchmark only at two trend sites.

California↗
USGS1966

Fluvial sediment in the little Arkansas River basin, Kansas

Characteristics and transport of sediment in the Little Arkansas River basin in south-central Kansas were studied to determine if the water from the river could be used as a supplemental source for municipal supply or would provide adequate recharge to aquifers that are sources of municipal and agricultural water supplies. During periods when overland 1low contributed a significant amount to streamflow, the suspended sediment in the Little Arkansas River at Valley Center averaged about 85 percent of clay, about 13 percent of silt, and about 2 percent of sand. The average annual suspended-sediment discharge for the water years 1958, 1959, 1960, and 1961 was about 306,000 tons, and about 80 percent of the load was transported during 133 days of the 1,461-day period. The average daily water discharge of 352 cubic feet per second for the period 1958-61 was more than the long-term (i}9-year) average of 245 cfs; therefore, the average annual sediment load for 1958-61 was probably greater than the average annual load for the same long-term period. Studies of seepage in a part of the channel of Kisiwa Creek indicated that an upstream gravel-pit operation yielded clays which, when deposited in the channel, reduced seepage. A change in plant operation and subsequent runoff that removed the deposited clays restored natural seepage conditions. Experiments by the Wichita Water Department showed that artificial recharge probably cannot be accomplished by using raw turbid water that is injected into wells or by using pits. Recharge by raw turbid water on large permeable areas or by seepage canals may be feasible. Studies of chemical quality of surface water at several sites in the Little Arkansas River basin indicate that Turkey. Creek is a major contributor of chloride and other dissolved solids to the Little Arkansas River and that the dissolved-solids content is probably highest during low-flow periods when suspended-sediment concentration is low. Data collected by the Wichita Water Department indicate that chloride concentrations are diminishing with time at sampled locations. and they receive recharge from rainwater and snowmelt moving through overlying alluvium and from storage in the De Chelly sandstone which encloses the east half of the diatreme. The quality of water from all areas is suitable for domestic use. However, special treatment may be necessary to make the water suitable for pulp processing.

Water Supply Paper↗
USGS2003

Organochlorine pesticides, PCBs, trace elements and metals in western pond turtle eggs from Oregon

With increased concern over the status of reptile populations globally, contaminant studies should be part of species evaluations. We analyzed eggs of western pond turtles from Fern Ridge Reservoir in western Oregon for 20 organochlorine (OC) pesticides or metabolites, 42 congener-specific polychlorinated biphenyls (PCBs), and 16 trace elements or metals. These eggs represent the first of this species analyzed. The OC pesticides and PCB residue concentrations in the western pond turtle eggs were generally low and similar to those found in eggs of snapping turtles from a remote site in Ontario, Canada. Western pond turtle eggs also contained mercury and chromium, which are metals of special concern. Although few reptilian eggs have been analyzed for metals, the 44.9 mug/g dry weight chromium in a western pond turtle egg in this study may be the highest reported in a reptilian egg. We found no significant difference in contaminant concentrations in eggs from nests in Oregon, where all turtle eggs failed to hatch compared to those where some eggs hatched. During this initial project, however, we were unable to assess fully the role of OCs, PCBs and other contaminants in the western pond turtle decline. Factors other than contaminants may be involved. In another study, snapping turtle eggs near the Great Lakes-St. Lawrence River basin were much more contaminated with evidence reported of effects on sex differentiation and reproductive endocrine function. Egg hatchability, the only reproductive parameter monitored, may not be the most sensitive endpoint. Other endpoints, including endocrine function, deformity rates, growth rates, and sex determination need study.

Northwest Science↗
USGS1946

The whitefish fishery of Lakes Huron and Michigan with special reference to the deep-trap-net fishery

This study of the whitefish fishery of Lakes Huron and Michigan includes: (1) a review of the available statistics of production, 1879-1942; (2) a detailed analysis of the annual fluctuations in the production and abundance of whitefish and in the intensity of the whitefish fishery in the State of Michigan waters of the lakes, 1929-1942, with special reference to the effects of fishing with deep trap nets; (3) an account of the bathymetric distribution and vertical movements of whitefish and certain other species; and (4) a report of field observations made in 1931 and 1932, as related particularly to the destruction of undersized whitefish by pound nets and deep trap nets. The main body of the manuscript and appendices A, B, and C, completed in March 1942, contain statistics through the year 1939. Since that time, records for the years 1940-1942 have become available. Because these additional data did not alter any of the conclusions of the manuscript but actually strengthened them, it was not deemed justifiable to expend the considerable amount of time and money that would be required to revise the study. The 1940-1942 records are therefore presented in appendix D. From a relatively high production in the earlier years of the period, 1879 to 1942, the yield of whitefish declined to a lower level about which the catch fluctuated until the late 1920's and early 1930's when a general increase in production occurred. This recent increase was higher and the subsequent decline more severe in the Michigan waters of Lake Huron than in other areas.

Lake Huron, Lake Michigan↗
USGS2003

Sediment dynamics drive contaminant dynamics

Many contaminants of greatest concern in San Francisco Bay, including mercury and PCBs, are primarily associated with sediment particles rather than dissolved in water. Therefore, the movement and fate of sediment determines the movement and fate of many contaminants in the Bay. Because of this close association, the RMP monitors and seeks to understand the quantity and movement of sediment suspended in the water. Through study of suspended sediment dynamics, the RMP is developing a better understanding of trends and patterns of contaminants and how the Bay will respond to management actions during the next several decades. Recent RMP efforts to develop predictive models of contaminant fate in the Bay have highlighted the fundamental importance of understanding sediment dynamics. Sediment movement in the Bay is determined by tides, wind, and freshwater inflow. Tides flood and ebb twice a day, wind typically is strongest in the afternoon, and freshwater inflow is greatest during the winter rainy season (see sidebar on next page). To characterize these fluctuations, the U.S. Geological Survey (USGS) began continuous monitoring of suspended sediment concentration in 1991. Continuous suspended sediment concentration monitoring stations were established in each major region of San Francisco Bay (Figure 1), establishing a continuous monitoring network. The sensors at each station measure the amount of material in the water every 15 minutes. Results are available on the internet at . In addition to the network, sensors have been deployed at as many as 14 additional sites in the Bay for periods of several months as part of focused studies of sediment transport in Bay locales of special interest.

California↗
USGS1934

Stream measurement work: Appendix 4 in Nineteenth biennial report of the State Engineer to the governor of Utah: 1933-1934

Stream measurement work under the usual co-operative agreement between the U.S. Geological Survey and the State Engineer continued during the biennium for the purpose of determining the water resources of the State. This work in Utah is part of the general plan for a systematic determination of the water resources of the United States begun by the Geological Survey in 1888. Records of stream flow on a few rivers in the West were taken as part of special studies on irrigation, in which connection gaging stations were established on the Bear, Weber, Provo, and Sevier rivers. The Bear River station at Collinston has been maintained continuously since that date.

Utah↗
USGS1943

Surface water supply of the United States, 1941, Part VIII, Western Gulf of Mexico basins

Th!s volume is one of a series of 14 reports presenting results or measurements of stage and flow made on streams, lakes, and reservoirs in the United States during the water year ending September 30, 1941. The work was begun !n 1888 in connection with special studies relating to irrigation. Measurements or the flow or streams and of the stage and contents of lakes and reservoirs have been made at about 9,120 gaging stations !n the United States and also at many gaging stations !n Alaska and Hawaii. In July 1941, 4,850 gaging stations were being maintained by the Geological Survey and cooperating organizations. Miscellaneous discharge measurements were made at many other points. In the execution of the work many State and private organizations have cooperated, either by furnishing data or by assisting !n collecting data. Cooperation of the first kind is acknowledged in connection with the description of each station affected; cooperation of the second kind is acknowledged on page 11.

Water Supply Paper↗
USGS1979

Geohydrology of the Cheyenne River Indian Reservation, South Dakota

Effective improvement of economic and social conditions of Indians living on the Cheyenne River Indian Reservation has been hampered by lack of adequate and reliable information about the quantity and quality of water supplies available for development. Compounding the problem is the recent fillinf of Oahe Reservoir, which flooded about 105,00 acres of Indian land, and the consequent relocation of many residents. This report summarizes the results of a water-resources study made at the request of the U.S. Bureau of Indian Affairs. It is intended to provide some of the needed information on water supplies that could be used to alleviate the problems mentioned. The cooperation and courtesy extended by many farmers, ranchers, and residents of the area contributed greatly to the success of the study. Special thanks are due to Mr. John Wall, U.S. Public Health Service, Eagle Butte, and to the personnel of the Land Operations and Conservation Unites of the U.S. Bureau of Indian Affairs, Eagle Butte.

South Dakota↗
USGS1997

Full Equations (FEQ) model for the solution of the full, dynamic equations of motion for one-dimensional unsteady flow in open channels and through control structures

The Full EQuations (FEQ) model is a computer program for solution of the full, dynamic equations of motion for one-dimensional unsteady flow in open channels and through control structures. A stream system that is simulated by application of FEQ is subdivided into stream reaches (branches), parts of the stream system for which complete information on flow and depth are not required (dummy branches), and level-pool reservoirs. These components are connected by special features; that is, hydraulic control structures, including junctions, bridges, culverts, dams, waterfalls, spillways, weirs, side weirs, and pumps. The principles of conservation of mass and conservation of momentum are used to calculate the flow and depth throughout the stream system resulting from known initial and boundary conditions by means of an implicit finite-difference approximation at fixed points (computational nodes). The hydraulic characteristics of (1) branches including top width, area, first moment of area with respect to the water surface, conveyance, and flux coefficients and (2) special features (relations between flow and headwater and (or) tail-water elevations, including the operation of variable-geometry structures) are stored in function tables calculated in the companion program, Full EQuations UTiLities (FEQUTL). Function tables containing other information used in unsteady-flow simulation (boundary conditions, tributary inflows or outflows, gate settings, correction factors, characteristics of dummy branches and level-pool reservoirs, and wind speed and direction) are prepared by the user as detailed in this report. In the iterative solution scheme for flow and depth throughout the stream system, an interpolation of the function tables corresponding to the computational nodes throughout the stream system is done in the model. FEQ can be applied in the simulation of a wide range of stream configurations (including loops), lateral-inflow conditions, and special features. The accuracy and convergence of the numerical routines in the model are demonstrated for the case of laboratory measurements of unsteady flow in a sewer pipe. Verification of the routines in the model for field data on the Fox River in northeastern Illinois also is briefly discussed. The basic principles of unsteady-flow modeling and the relation between steady flow and unsteady flow are presented. Assumptions and the limitations of the model also are presented. The schematization of the stream system and the conversion of the physical characteristics of the stream reaches and a wide range of special features into function tables for model applications are described. The modified dynamic-wave equation used in FEQ for unsteady flow in curvilinear channels with drag on minor hydraulic structures and channel constrictions determined from an equivalent energy slope is developed. The matrix equation relating flows and depths at computational nodes throughout the stream system by the continuity (conservation of mass) and modified dynamic-wave equations is illustrated for four sequential examples. The solution of the matrix equation by Newton's method is discussed. Finally, the input for FEQ and the error messages and warnings issued are presented.

Water-Resources Investigations Report↗
USGS2007

Possible ancient giant basin and related water enrichment in the Arabia Terra province, Mars

A circular albedo feature in the Arabia Terra province was first hypothesized as an ancient impact basin using Viking-era information. To test this unpublished hypothesis, we have analyzed the Viking era-information together with layers of new data derived from the Mars Global Surveyor (MGS) and Mars Odyssey (MO) missions. Our analysis indicates that Arabia Terra is an ancient geologic province of Mars with many distinct characteristics, including predominantly Noachian materials, a unique part of the highland-lowland boundary, a prominent paleotectonic history, the largest region of fretted terrain on the planet, outflow channels with no obvious origins, extensive exposures of eroded layered sedimentary deposits, and notable structural, albedo, thermal inertia, gravity, magnetic, and elemental signatures. The province also is marked by special impact crater morphologies, which suggest a persistent volatile-rich substrate. No one characteristic provides definitive answers to the dominant event(s) that shaped this unique province. Collectively the characteristics reported here support the following hypothesized sequence of events in Arabia Terra: (1) an enormous basin, possibly of impact origin, formed early in martian history when the magnetic dynamo was active and the lithosphere was relatively thin, (2) sediments and other materials were deposited in the basin during high erosion rates while maintaining isostatic equilibrium, (3) sediments became water enriched during the Noachian Period, and (4) basin materials were uplifted in response to the growth of the Tharsis Bulge, resulting in differential erosion exposing ancient stratigraphic sequences. Parts of the ancient basin remain water-enriched to the present day. ?? 2007 Elsevier Inc. All rights reserved.

Icarus↗
USGS2011

The story of the Hawaiian Volcano Observatory -- A remarkable first 100 years of tracking eruptions and earthquakes

The year 2012 marks the centennial of the Hawaiian Volcano Observatory (HVO). With the support and cooperation of visionaries, financiers, scientists, and other individuals and organizations, HVO has successfully achieved 100 years of continuous monitoring of Hawaiian volcanoes. As we celebrate this milestone anniversary, we express our sincere mahalo—thanks—to the people who have contributed to and participated in HVO’s mission during this past century. First and foremost, we owe a debt of gratitude to the late Thomas A. Jaggar, Jr., the geologist whose vision and efforts led to the founding of HVO. We also acknowledge the pioneering contributions of the late Frank A. Perret, who began the continuous monitoring of Kīlauea in 1911, setting the stage for Jaggar, who took over the work in 1912. Initial support for HVO was provided by the Massachusetts Institute of Technology (MIT) and the Carnegie Geophysical Laboratory, which financed the initial cache of volcano monitoring instruments and Perret’s work in 1911. The Hawaiian Volcano Research Association, a group of Honolulu businessmen organized by Lorrin A. Thurston, also provided essential funding for HVO’s daily operations starting in mid-1912 and continuing for several decades. Since HVO’s beginning, the University of Hawaiʻi (UH), called the College of Hawaii until 1920, has been an advocate of HVO’s scientific studies. We have benefited from collaborations with UH scientists at both the Hilo and Mänoa campuses and look forward to future cooperative efforts to better understand how Hawaiian volcanoes work. The U.S. Geological Survey (USGS) has operated HVO continuously since 1947. Before then, HVO was under the administration of various Federal agencies—the U.S. Weather Bureau, at the time part of the Department of Agriculture, from 1919 to 1924; the USGS, which first managed HVO from 1924 to 1935; and the National Park Service from 1935 to 1947. For 76 of its first 100 years, HVO has been part of the USGS, the Nation’s premier Earth science agency. It currently operates under the direction of the USGS Volcano Science Center, which now supports five volcano observatories covering six U.S. areas—Hawaiʻi (HVO), Alaska and the Northern Mariana Islands (Alaska Volcano Observatory), Washington and Oregon (Cascades Volcano Observatory), California (California Volcano Observatory), and the Yellowstone region (Yellowstone Volcano Observatory). Although the National Park Service (NPS) managed HVO for only 12 years, HVO has enjoyed a close working relationship with Hawaiʻi Volcanoes National Park (named Hawaii National Park until 1961) since the park’s founding in 1916. Today, as in past years, the USGS and NPS work together to ensure the safety and education of park visitors. We are grateful to all park employees, particularly Superintendent Cindy Orlando and Chief Ranger Talmadge Magno and their predecessors, for their continuing support of HVO’s mission. HVO also works closely with the Hawaiʻi County Civil Defense. During volcanic and earthquake crises, we have appreciated the support of civil defense staff, especially that of Harry Kim and Quince Mento, who administered the agency during highly stressful episodes of Kīlauea's ongoing eruption. Our work in remote areas on Hawaiʻi’s active volcanoes is possible only with the able assistance of Hawaiʻi County and private pilots who have safely flown HVO staff to eruption sites through the decades. A special mahalo goes to David Okita, who has been HVO’s principal helicopter pilot for more than two decades. Many commercial and Civil Air Patrol pilots have also assisted HVO by reporting their observations during various eruptive events. Hawaiʻi’s news media—print, television, radio, and online sources—do an excellent job of distributing volcano and earthquake information to the public. Their assistance is invaluable to HVO, especially during times of crisis. HVO’s efforts to provide timely and accurate scientific information about Hawaiian volcanoes and earthquakes succeed only because of you, our receptive and keenly aware public. By following the activity of Hawaiʻi’s active volcanoes through our daily eruption updates posted on the HVO website, viewing HVO webcam images, reading our weekly “Volcano Watch” articles, and attending our public lectures, you help us to ensure that you can live safely with Hawaiʻi’s dynamic volcanoes. To everyone who has shared in HVO’s reaching this milestone—100 years of continuous volcano monitoring—we extend our deepest gratitude. Mahalo nui loa!

Hawai'i↗
USGS1977

Mineral resources of the Tracy Arm-Fords Terror Wilderness Study Area and vicinity, Alaska

The Wilderness Study Area consists of about 322,300 hectares (1,250 square miles or 796,400 acres) on the southwest side of the Coast Range in southeastern Alaska about 72 km (45 miles) southeast of Juneau, Alaska (fig. 1). An additional 142,800 hectares (550 square miles or 352,900 acres) lying in part between the study area and the International Boundary and in part contiguous to the southwest of the study area were studied because of their importance to the evaluation of the study area itself. Unless otherwise specified, the term Study Area as used in this report includes both the formally designated study area and these contiguous areas. The general area is one of spectacular scenery, with fiords, forests, glacier-covered peaks to 2,470 m (8,095 feet) high, tidewater glaciers, icebergs, and some broad river valleys. No roads or maintained trails or permanent residents are present, and access is only by specially arranged water or air transport. Present human use of the area is related to recreation or mineral-resource exploration.

Alaska↗
USGS1965

Hydrology of subsurface waste disposal, National Reactor Testing Station, Idaho: Annual progress report for 1964

The principal purpose of the past research program on geohydrology at the NRTS has been to acquire information on the physical and geochemical environment of the station. This requires a knowledge of the composition and structure of the earth materials underlying the plain, the inventory of the water resources, the dynamics of natural and man-produced changes in the hydrologic regimen, details of the hydrologic cycle, and relevant geochemical processes. The Geological Survey in the course of its early studies by Nace and others (IDO 22033-34-USGS) obtained, compiled, and analyzed a considerable amount of basic geologic and hydrologic information on these subjects. These basic goals were expanded and carried forward to guide the continuing research work. Jones (IDO 22042-USGS) emphasized the use of borehole geophysics and specialized down-hole techniques. Olmsted (IDO 22043-USGS) made a preliminary appraisal of the nature and distribution of the quality of ground water beneath the Station. Their work has been continued and elaborated upon by Morris and others (IDO 22044-USGS, 46-USGS) and the present report with greater emphasis on the regional geology and hydrology. This involved some procurement of needed information but, for the most part, involved a continued evaluation and refinement of data and results that had been acquired in the past. The Geological Survey also encouraged a more comprehensive study of the regional geologic structure including the use of aeromagnetic, gravity, and seismic geophysical techniques and cosponsored a seminar on it in 1964. Along with this investigation and study of the regional geology and of hydrologic principles operative in the basalt environment, and made possible because of it, research continues on the-hydrologic aspects of the disposal of low-level aqueous waste to the environment.

Idaho↗
USGS1916

Guidebook of the western United States: Part C - The Santa Fe route, with a side trip to Grand Canyon of the Colorado

The United States of America comprise an area so vast in extent and so diverse in natural features as well as in characters due to human agency that the American citizen who knows thoroughly his own country must have traveled widely and observed wisely. To 'know America first' is a patriotic obligation, but to meet this obligation the railroad traveler needs to have his eyes directed toward the more important or essential things within his field of vision and then to have much that he sees explained by what is unseen in the swift passage of the train. Indeed, many things that attract his attention are inexplicable except as the story of the past is available to enable him to interpret the present. Herein lie the value and the charm of history, whether human or geologic. The present stimulus given to travel in the home country will encourage many thousands of Americans to study geography at first hand. To make this study most profitable the traveler needs a handbook that will answer the questions that come to his mind so readily along the way. Furthermore, the aim of such a guide should be to stimulate the eye in the selection of the essentials in the scene that so rapidly unfolds itself in the crossing of the continent. In recognition of the opportunity afforded in 1915 to render service of this kind to an unusually large number of American citizens, as well as to visitors from other countries, the United States Geological Survey has prepared a series of guidebooks covering four of the older railroad routes west of the Mississippi. These books are educational in purpose, but the method adopted is to entertain the traveler by making more interesting what he sees from the car window. The plan of the series is to present authoritative information that may enable the reader to realize adequately the scenic and material resources of the region he is traversing, to comprehend correctly the basis of its development, and above all to appreciate keenly the real value of the country he looks out upon, not as so many square miles of territory represented on the map in a railroad folder by meaningless spaces, but rather as land - real estate, if you please - varying widely in present appearance because differing largely in its history and characterized by even greater variation in values because possessing diversified natural resources. One region may be such as to afford a livelihood for only a pastoral people; another may present opportunity for intensive agriculture; still another may contain hidden stores of mineral wealth that may attract large industrial development; and taken together these varied resources afford the promise of long-continued prosperity for this or that State. Items of interest in civic development or references to significant epochs in the record of discovery and settlement may be interspersed with explanations of mountain and valley or statements of geologic history. In a broad way, the story of the West is a unit, and every chapter should be told in order to meet fully the needs of the tourist who aims to understand all that he sees. To such a traveler-reader this series of guidebooks is addressed. To this interpretation of our own country the United States Geological Survey brings the accumulated data of decades of pioneering investigation, and the present contribution is only one type of return to the public which has supported this scientific work under the Federal Government. In preparing the description of the country traversed by the Santa Fe Route the geographic and geologic information already published as well as unpublished material in the possession of the Geological Survey has been utilized, but to supplement this material Mr. Darton made a field examination of the entire route in 1914. Information has been furnished by Erasmus Haworth, J. E. Todd, and R. T. Hill, as well as by others whose writings are listed in the bibliography at the end of the text. Cooperation has been rendered by the United States Reclamation Service and by bureaus of the Department of Agriculture. Railroad officials and other citizens have also generously given their aid, and other members of the Survey have freely cooperated in the work. For the purpose of furnishing the traveler with a graphic presentation of each part of his route, the accompanying maps, 25 sheets in all, have been prepared, with a degree of accuracy probably never bsfore attained in a guidebook, aiid their arrangement has been planned to meet the convenience of the reader. The special topographic surveys necessary to complete these maps of the route were made by W. O. Tufts.

Bulletin↗