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 detailed information concerning the coal deposits of the Ashland field set forth in this report has been obtained in the course of an investigation that has been conducted both as a part of the United States Geological Survey's general systematic study of western coal lands and as an aid in the administration of the public lands. With the information obtained on the location of outcrops, the number, distribution, and thickness of coal beds, the accessibility of the coal, and the thickness of the overburden, the public lands of the region are classified as to their coal value; coal-bearing lands are differentiated from noncoal-bearing lands; and the administration of the coal-land leasing law is facilitated.

From abstract: The crystal cavities present in the mineral complex of the New Jersey traprock region have long excited the interest of mineralogists. In 1914 Fenner made the first detailed and comprehensive study of these cavities and suggested that babingtonite was the original mineral. Soon after this anhydrite was found occupying parts of some of the cavities at one of the quarries. At this time, too, Wherry concluded that glauberite was the original mineral of some of the cavities because of his studies of similar crystal cavities in Triassic shale at different places.

From abstract: The largest single metal-mining operation in the history of mining in Colorado has been developed at Climax, as a result of the increased use of molybdenum in the steel and other industries. Production of molybdenum at Climax was notable for a short period during the World War; it ceased from April 1919 to August 1924 but since then has shown a steady increase. In 1930 from 1,000 to 1,200 tons of ore was milled daily, using only one unit of the 2,000-ton mill. The mine has a reserve of broken ore sufficient to furnish 2,000 tons daily for 3 years and is being developed to continue to furnish this and a still further increased output as the use of the metal may warrant.

From abstract: The report is limited to the geology of lode deposits in the northwestern part of the Boise Basin which are in or near mines that were in operation at the time of visit, in 1930. Owing to the recent inactivity of the formerly rich placer (leposits, there is nothing essential regarding them to add to Lindgren's report published in 1898. The area studied is underlain by granitic rock of the Idaho batholith, which is cut by dikes of Miocene(?) age. These dikes are dacite porphyry (intruded early) ; rhyolite porphyry, granophyre porphyry, and granite porphyry (closely related in character and age) ; and several basic varieties (of which some, at least, are of relatively late origin). Diorite porphyry dikes, of undetermined age but probably older than all of those named above, are also present.

From abstract: The Monument Valley-Navajo Mountain region is part of the Colorado Plateau and includes about 1,100 square miles in San Juan County, southeastern Utah, lying between the San Juan and Colorado Rivers on the north and the Utah-Arizona State line on the south. Included in the region are Navajo Mountain, the Rainbow Natural Bridge, and a part of the picturesque Monument Valley.

From introduction: The purpose of this paper is to describe the geology and mineral resources of a part of the Copper River Basin between the Richardson Highway and the valley of the Klutina River, together with small areas east of the highway and west of the river. For convenience in reference this area is called the Tonsina district, as the Tonsina River and Tonsina Lake are conspicuous local geographic features, and the Tonsina Road House, on the highway at the crossing of the river, is one of the oldest and best-known settlements in the Copper River Basin.

From abstract: The Moose Creek area is in the western part of the Matanuska Valley, in south-central Alaska, about 165 miles by railroad north of the coast at Seward. Coal deposits in the valley have been known since the early 1890's, and there have been producing mines since 1916, but the annual production is only about 40,000 tons, or less than one-third of the total amount consumed in the Territory. Early in 1931 Congress authorized the investigation of mineral resources in areas tributary to the Alaska Railroad, which is Government owned and operated, for the purpose of stimulating development and hence increasing the traffic and revenue of the railroad. The technical work of carrying on these studies was entrusted by Col. O. F. Ohlson, general manager of the railroad, to the United States Geological Survey. One of the investigations undertaken was that of the Moose Creek area, where small coal mines are in operation. Difficulties have been encountered in these mines, owing to the faulted character of the formation, which causes unproductive work in mining and also produces a large percentage of fine coal, which is unsuitable for sale in distant markets. Field examination indicated that more favorable mining conditions …

From introduction: The district described in this report is a triangular area covering about 300 square miles in the southwestern part of the Talkeetna Mountains. The Kashwitna River forms the northern boundary, the Susitna Valley flats the western, and the Willow Creek gold district, which is in the extreme southwestern part of the Talkeetna Mountains, the southern. As the area examined is not a distinct geographic unit, its boundaries being arbitrarily chosen and set only by the limitation of time spent in the field, a description of its geography applies to practically the entire western and southern portions of the Talkeetna Mountains, of which it is a part.

From Abstract: "The following report is essentially a description of the mineral deposits that have been found in this region and of the status of mining in 1933."

From abstract: The Coastal Plain of South Carolina extends from the Atlantic Ocean inland a distance ranging from 120 to 150 miles to the Fall Line, where it adjoins the Piedmont province. It includes an area of more than 20,000 square miles, or nearly two-thirds of the State, whose total area is 30,981 square miles, of which 494 square miles is water. The geographic divisions of the Coastal Plain are the marine coastal terraces, or "low country", which stand less than 270 feet above sea level, and the Aiken Plateau, the High Hills of Santee, the Richland red hills, and the Congaree sand hills.

From introduction: This report describes the deposits of analcite in the Green River formation, to compare them with other similar deposits, and to present them with other similar deposits, and to present the observations and inferences that led him to explain them as alteration products of volcanic ash that fell into an ancient saline lake. The report also records the occurrence of several thin beds of sepiolite, or meerschaum, in the Green River formation and presents new data on the molds of saline minerals of the Green River formation whose determination affects directly the interpretation of the analcite and sepiolite deposits.

From foreword: This report describes the upper cretaceous floras and rocks south of the Brooks Range in Alaska.

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.

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.

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.

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."

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.

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.

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.

From abstract: The San Juan country includes an area of about 3,800 square miles east of the Colorado River in San Juan County, southeastern Utah. This paper is based on reconnaissance geographic and geologic surveys made in 1910, 1915, 1925, and 1927-29.

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.

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.