A report on the exploration and survey of the Chakachamna-Stony Region of Alaska.

Introduction: At the end of the field season the writer visited the mining plants in the Fortymile district, and this paper, resulting from these examinations, is intended mainly to sketch the present progress of mining development in the district.

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.

From abstract: The region described in this report includes a foothill belt of the San Emigdio and Tehachapi Mountains along the southern border of San Joaquin Valley. The belt displays portions of the rugged granitic cores of the mountains and also rocks of Eocene, Oligocene, Miocene, Pliocene, and Pleistocene age. Although there is thus a complete representation of the geologic series from the Eocene to the Pleistocene, some portions of the different series are wanting because of major faults and overlaps. The thickness of the Tertiary rocks (Eocene to Pliocene) varies considerably but has a maximum of about 29,000 feet. Miocene and Pliocene rocks cover most of the area investigated.

From introduction: The investigations on which the greater part of this report is based were carried on by E. T. Hancock, the senior author, during the summer of 1911. They were undertaken by the United States Geological Survey under a comprehensive plan for collecting information about the undeveloped fuel resources of the Western States, both as a step toward the conservation of the coal resources of the United States and as a means of supplying the demand for information concerning the many valuable coal fields of the Western States.

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.

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.

Description of geology in Minnesota and explanations of glacial drift within the state an immediate surroundings (Wisconsin, Iowa, North Dakota and South Dakota) with sections detailing the movement of each glacier and relevant geological notes. Index starts on page 147.

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.