Abstract: Reconnaissance of Red Rock Valley was begun on December 10, 1953, and completed on February 11, 1954. The mines in the region were investigated and all exposures of Salt Wash were walked. Paleostream directions and alterations of the sandstones were observed and recorded on a base map. No important new mineralization was discovered-and the area is considered to be of no commercial significance if judged by the outcrops alone. However, a vast amount of Salt Wash lies at slight depth directly to the east of the investigated area.

Introduction: Reconnaissance for uranium in central and southwestern Arkansas was carried out as a joint project of the U.S. Atomic energy Commission and the U.S. Geological Survey during March and May 1954. The project was planned as an investigation of several areas of known abnormal radioactivity, and as a search for others, by airborne and ground radiometric reconnaissance.

Data which determine points on the Hugoniot curves of fourteen solids are given in the technical report.

Paths of trip points of Mach reflections produced by 0.5-oz pentolite detonations have been observed for various burst heights. The slopes, Y, at points on the curved path are found to vary from values of Y predicted from plane shock wave data. This discrepancy is attributed to the shock strength conditions at the early inception of the Mach reflection, which later influence the triple point equilibrium, and in lesser degree to radius of curvature effects.