Introduction: Part 2 of the Systematic Report continues and concludes the study of the Mollusca from the Miocene and lower Pliocene of Virginia and North Carolina. One hundred and nineteen species, only a fraction of the known fauna, are reviewed and 66 additional species are described and figured. (See faunal chart, pp. 180-183.) The report upon the gastropods suffers from the same shortcomings obvious in the work on the pelecypods. Most of the material is from old collections made before the importance of the exact placing of the fossil locality both areally and vertically was recognized. Many of the citations of outcrops are vague and the sections generalized. Detailed field studies, particularly on the zoning of the Yorktown formation in southern Virginia and northern North Carolina, were begun later by Wendell P. Mansfield, but he died in the summer of 1939 before the completion of the work.

From introduction: This report details the results of a geological survey of the Libby Quadrangle, Montana.

From abstract: Geophysical prospecting by gravity methods has been successful in finding new deposits in the [Camaguey] district, and the present studies have brought out new information on the localization and attitudes of the known deposits that may be of assistance in planning future geophysical work.

From abstract: Aluminous lateritic soil containing as much as 50 percent of alumina (A120) Is found in several places in the Republic of Haiti. The largest deposits are on the Rochelois Plateau southwest of Miragoane on the Southern Peninsula. Mapping and drilling of the deposits indicate fifteen million long tons in place (dried basis). It is estimated that a minimum of 10 million long tons of this reserve is recoverable. The average chemical composition of this material is as follows: A1203, 46.8 percent; SiO2, 3.4 percent; T1O2, 2.8 percent; Fe20, 21.9 percent ; P206, 0.6 percent ; MnO5, 0.5 percent ; and loss on ignition, 24.1 percent. Other localities in which similar lateritic soil occurs are Beaumont in the Massif de la Hotte ; the vicinity of Savane Zombi in the Massif de la Selle ; and Savane Terre Rouge on the plateau northwest of Gonaives. In none of these regions were large deposits found.

From Abstract: "This report deals with an area of 425 square miles in the western part of Texas, immediately south of the New Mexico line. The report describes the geology of the area, that is, the nature of its rocks, tectonics, and surface features, and the evidence that they give as to the evolution of the area through geologic time. Incidental reference is made to the geology of surrounding regions in order to place the area in its environment."

From abstract: Many small deposits of optical calcite (Iceland spar) were discovered in the States of Chihuahua, Durango, Sonora, and Sinaloa from early in 1942 to late in 1944. Exploration that began in Sonora led to the discovery of commercial deposits in the eastern part of that State, and subsequently other deposits were found and mined in southwestern and northeastern Chihuahua and in western and central Durango. The largest deposits can be reached by foot or by horse in from 1 to 3 hours from the nearest truck roads, but some of the small deposits are 1 to 3 days by horse from the nearest roads.

From abstract: The Talamantes district, 20 kilometers east of Parral in southern Chihuahua, has been the second largest producer of manganese ore in Mexico. Production, which started during World War I and has been more or less continuous since 1930, has totaled about 50,000 tons of ore with an average manganese content of 40 or 41 percent. The mines are on the Mesa de Talamantes, which is underlain by folded Cretaceous (?) limestone, overlain unconformably by gently dipping Tertiary rhyolite flows and tuff, volcanic breccia, agglomerate, and tuffaceous sandstone. Steeply dipping normal faults of northerly trend cut the rock and divide the mesa into a series of blocks.

From abstract: Manganese has been reported from 335 deposits in 20 of the 30 States and Territories of Mexico. The production of manganese ore prior to 1942, according to published figures, amounted to about 54,000 tons. For the year 1942 production rose to 35,000 tons, for 1943 to 70,503 tons, and for 1944 to 80,671 tons; but for 1945 it dropped to a little less than 52,000 tons, and during 1946 it continued to drop. Up to the end of 1941 Chihuahua had produced about half the manganese ore from Mexico; San Luis Potosi produced about 17 percent, and Baja California and Zacatecas each about 10 percent. In 1942 Baja California became the chief producer; Durango, Chihuahua, and Zacatecas each yielded somewhat less. During that year the ore came from 76 deposits, of which only 30 yielded more than 500 tons each.

Report discussing the U.S. Geological Survey's investigation of the radioactivity measurements of asphalltites, coals and shales found in Tennessee, Kentucky, West Virginia, and Pennsylvania.

Report discussing the U.S. Geological Survey's investigation of the radioactivity of sedimentary rocks in Oklahoma and Kansas.