A report which describes the hydrothermal alteration of numerous outcrop samples collected in the vicinity of Mount Hood, as well as drill cuttings from 13 of the geothermal drill holes for which we were able to obtain sample splits.

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 describing the geology of a few counties in Oregon. Strata is exposed that ranges in age from pre-Tertiary to Quaternary.

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 abstract: Jurassic ammonites of late Bathonian to middle Callovian Age have been found in 12,000-13,000 feet (3,660-3,960 m) of strata exposed in the area near and south of Izee and Seneca in east-central Oregon. Ammonites of early Callovian Age and possibly also late Bathonian Age occur in several hundred feet of black shale exposed along Dennett Creek near Mineral, Idaho. Early Callovian ammonites also occur in similar black shale exposed on the Oregon side of Snake River Canyon about 32 miles (52 km) south of the northeast corner of Oregon.

From introduction: This report is based on a hasty reconnaissance made during the summer of 1910 and on several explorations made by the writer in the years 1900 to 1905.

From introduction: The aim of the present paper is to put on record such observations relating to the general geology of the region traversed as it is thought may be of interest, more particularly to the people of Idaho and Oregon, and also in certain instances serve to supplement the report referred to on artesian conditions.

From introduction: The two papers published here refer practically to the whole region included in the National Park. The one. Part I, treats primarily of the geology, the development of the great volcano, Mount Mazama, and its collapse, which gave birth to Crater Lake; the other, Part II, deals with the petrography, and gives a special description of the various rocks occurring in the park.

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: This report presents the results of a rather complete reconnaissance of the Baker quadrangle, Oregon, carried out during brief studies of some mining districts in and near the area.

From introduction: The observations recorded in this paper were made during a rapid reconnaissance from east to west through the central part of Oregon in the summer of 1903, and are in continuation of similar work in the same general region previously done by the author, reports concerning which have been published.

From abstract: The copper deposits near Keating, Oreg., in the southwestern foothills of the Wallowa Mountains, form part of a series distributed along a belt over 75 miles long. The belt containing copper deposits extends from a point west of North Powder to and beyond the Snake River at Homestead.

From introduction: This report embodies the results of investigations of three gold mining districts in Josephine and Curry Counties, southwestern Oregon.

From Introduction: "The Opalite quicksilver district includes two deposits with a considerable past production, one deposit with a small production, and one unproved prospect. These deposits are located along the circumference of a semicircular area that extends from a short distance west of McDermitt, Nev., for about 20 miles along the Oregon-Nevada State boundary. (See fig. 34). The area thus includes parts of Humboldt County, Nev., and Malheur County, Oreg.; almost the entire production has been derived from the portion in Oregon."

From abstract: This report presents the results of a reconnaissance of most of the mining districts of Oregon east of the Cascade Range, with the exception of the districts in the Sumpter quadrangle. The districts described are distributed through an area roughly coincident with the Blue Mountains, which extend over much of the northeast quarter of the State.

From Abstract: Two areas and their included mineral deposits, situated in Josephine County, southwestern Oregon, are described in this report. They lie within the Klamath Mountains, a region which is made up for the most part of rugged ridges trending in various directions but which, when viewed from higher summits, resembles a dissected plateau and is known as the Klamath peneplain. Rocks of both igneous and sedimentary origin are abundant in the districts described. The marine sedimentary rocks of the areas comprise a thick series of Carboniferous strata, with some interbedded volcanic rocks, and portions of the Galice formation, of Jurassic age, and of an Upper Cretaceous formation. The rocks of fluviatile origin include Tertiary conglomerate, Pleistocene valley fill, termed the " Llano de Oro formation," and somewhat later Pleistocene gravel and alluvium, in part glacial debris. Recent gravel is found along the present streams. The igneous rocks include several varieties of greenstone of probable Paleozoic and Mesozoic age and serpentine of late Jurassic or early Cretaceous age.

From Introduction: "The Riddle nickel deposit is on Nickel Mountain, also called Piney Mountain, about 5 miles northwest of Riddle, Douglas Country, Oreg. (fig. 20). The deposit is an unevenly distributed surficial blanket, containing the nickel silicate garnierite, which rests upon peridotitic rocks on the western, southern, and southeastern slopes of the mountain above an elevation of 2,000 feet. It is on the Southern Pacific Railroad, and it is about 230 miles by highway south of Portland. A poorly conditioned dirt road about 5 miles long connects the town with the nickel deposit."

From Scope of Report: "During the summer of 1940, 34 days were spent in a preliminary study of the quicksilver deposits in the Steens and Pueblo Mountains. Nearly all of the quicksilver prospects were examined and mapped, and the general geology of the east flank of the mountains from north of Andrews to Denio was reconnoitered."

Report discussing the search for uraniferous coal in areas of California, Oregon, and Nevada. The reconnaissance and its results are described in sections divided by regions searched.

From introduction: "This report briefly describes the geology of an area of about 750 square miles in Jefferson, Wasco, Crook, and Wheeler Counties, Oregon."

From purpose and scope: This report describes methods for estimating the magnitude and frequency of floods at ungaged sites on streams with unregulated flow in eastern Oregon. The purpose is to provide a method to estimate flood magnitude and frequency and to present the supporting data. The report is based on data from nearly all unregulated streams (or data from regulated streams prior to their regulation) where gaging stations have been operated.

From introduction: The purpose of this report is to provide sufficient geologic and hydrologic data to aid in the future development of ground- and surface-water supplies. The objectives were to determine the availability, quantity, and quality of ground- and surface-water supplies with reference to problems of development, and to determine the limitations of the water resources.

Abstract: The various components of inflow and outflow to and from the lake and their relative magnitudes were identified. In 1972 water year the total inflow to the lake was 200,000 acre-feet, but it was only 75,000 acre-feet in 1973 water year. In 1972 water year the Donner and Blitzen River contributed 55 percent of the inflow, with Silvies River, direct precipitation, and Sodhouse Spring contributing 28, 13, and 4 percent respectively. Om 1973 the Donner and Blitzen River contributed 61 percent of the inflow. The Silvies River, direct precipitation, and Sodhouse Spring contributed 1, 25, and 12 percent respectively. Ground-water inflow, other than Sodhouse Spring, appears to be negligible. In 1972 water year, 81 percent of the outflow was by evapotranspiration and 19 percent was surface outflow through The Narrows. In 1973, 96 percent of the outflow was by evapotranspiration and 4 percent was surface outflow through The Narrows. Ground-water outflow is negligible.

From introduction: Of the various hydrologic hazards in our environment, the mass movement of earth material caused by excess moisture can be one of the most destructive. These events often go unnoticed because they occur in unpopulated mountainous terrain during winter seasons. This was not the case in December 1964, when a major debris flow occurred in the Cave Creek drainage of the Oregon Caves National Monument. In March 1982, the National Park Service (NPS) requested a study be made to appraise the possibility of a recurrence of the 1964 debris flow in the interest of safeguarding the public and employees of the National Park Service.