Report describing the results of experiments to test for radon and uranium in ground water from samples taken near Hylas, Virginia.

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.

Abstract: In the Blue Ridge Province of northern Virginia, Maryland, and southern Pennsylvania, Lower Cambrian beds are underlain by a thick sequence of greenstone and interbedded sedimentary rocks known as the Catoctin Formation. An area near Luray, Va., was studied to determine the thickness of the formation, its relationship to overlying and underlying rocks, and the original nature of the lavas from which the Catoctin greenstone was derived. There the Catoctin Formation lies unconformably on granitic rocks. Its basal sedimentary layer ranges from a few inches to 150 feet in thickness and contains pebbles of underlying basement rocks. The erosion surface beneath the Catoctin is irregular, and in several places, hills as much as 1,000 feet high were buried beneath the Catoctin lavas. No important time break is indicated between the deposition of the Catoctin Formation and the overlying Cambrian sediments. The original Catoctin lavas were basaltic and were probably normal plateau basalts. Columnar joints, amygdules, sedimentary dikes, flow breccias, low-dipping primary joints, and other primary structures are well preserved.

From abstract: Cassiterite was discovered along Irish Creek in the Blue Ridge in the northern part of Rockbridge County, Va., in 1846, but active prospecting and development work were not begun until 1884. The production has been small, probably less than 1,000 tons of ore, and has come chiefly from workings on Panther Run, a small tributary near the headwaters of Irish Creek.

From abstract: The Jonesville district is in central Lee County in the extreme southwest corner of Virginia. It includes an area that is 25 miles long from northeast to southwest and averages 6 miles in width. Most of the district lies within a broad lowland named the Powell Valley, but the district includes Wallen Ridge, which bounds Powell Valley on the southeast.

From abstract: The Cedar Creek manganese mining district is in the southwestern part of Frederick County and the northwestern part of Shenandoah County, Virginia. The manganese ore consists chiefly of the oxides pyrolusite and psilomelane, and forms replacement pockets and fracture fillings in the Oriskany sandstone and in residual sandy clay and chert derived from the New Scotland limestone. Both these formations are of Devonian age, and both form low ridges. The minable bodies have been deposited by ground water in the zone of weathering, and most of them lie above present ground-water level. The manganese-bearing formations, together with the older and younger formations exposed in Cedar Creek Valley, have been compressed into numerous folds, and at the southwestern end of the district one of these folds passes into a normal fault with a displacement of 1,000 feet or more.

From introduction: This study was undertaken as part of the U.S. Geological Survey's (USGS) Reactor Hazards Reduction Program. One of the goals of this program is to contribute to the growing recognition and cataloging of Cenozoic faults in the Atlantic Coastal Plain. Once the faults are recognized and cataloged, the stress field and resulting tectonic framework that produced these faults can be determined. This study defines the stratigraphic and structural relationships of a tectonically anomalous area in the vicinity of Hopewell, Va.

From abstract: "This report is a survey of present and potential production of monazite from part of the Maryland-Florida section of the Atlantic Coastal Plain."

Report discussing the U.S. Geological Survey's investigation aimed at finding a location with an abundance of black shale, and determining the amount of uranium in the shale.

Report about monzanite placers in streams of the western part of the Piedmont in Virginia, North Carolina, South Carolina, and Georgia. The objective of the report is to describe local monazite deposits, to determine geologic controls of monazite placers in the southeastern Piedmont, and to evaluate placer potentialities of the area.

Report discussing the U.S. Geological Survey's investigation of uraniferous coals and shales found in southern West Virginia and southwestern Virginia. Information regarding the general area, stratigraphy, structural geology, radioactivity of measured sections, radioactivity of collected samples, and conclusions are included.

From abstract: This report describes four species of Ostreidae from the Upper Cretaceous of the Gulf region. The zones that the species characterize lie either in the upper part of the Austin chalk or in beds of upper Austin age.

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 introduction: In presenting this paper the writer has two objects in view. The first is to add to the general knowledge respecting the geology of this central district [Appalachian coal basin]. The groups determined in this region will be carried over the adjoining territory if they can be distinguished and they afford a type-section of the Coal-measures where they are probably best developed. The results are not put forth as final, but as representing the most probable conclusions from the observed facts.

This report follows mineral-resource surveys taken at Barbours Creek and Shawvers Run Wilderness study areas in Craig County, Virginia. This report provides the findings of these studies, mineral deposits primarily.

The following report analyzes the geology of the Waterford quadrangle and the Virginia part of the Point of Rocks quadrangle.

This report analyses tree rings of large Pinus taeda L. trees "growing near a drainage ditch in the Great Dismal Swamp" and concludes that these rings are "datable and hydrologically sensitive." It includes tables and graphs.

From introduction: The object of this memoir is to give some account of the geology of the lower Potomac formation in Virginia, where it is perhaps most typically developed.

This report evaluates the quality of the ground water in seven small contiguous stream basins in the coal area of Buchanan County, Virginia.

From abstract: This study used a rainfall-runoff model to determine if land-use changes associated with surface mining in the Tug Fork basin have affected basin streamflow characteristics.

The following report documents the geological mapping of the Harpers Ferry quadrangle, Virginia, Maryland, and West Virginia, from between 1989 and 1990.