Report issued by the U.S. Bureau of Mines on the study of contamination of cores obtained with conventional core barrels. The effect of the oil-based drilling fluid and analysis of the cores are presented. The report includes tables, graphs, and illustrations.

From introduction: An autunite deposit in the SW 1/4 sec. 25, T. 10 N., R. 13 W. San Bernardino meridian, was visited by F. M. Chace on May 6 and 15, 1950. The deposit is about 100 yards west of a north-south country road and is at an altitude of approximately 2,775 feet. The autunite-bearing tuffaceous sandstone strikes N. 35-40 W. and dips 20 -25 SW. It has been traced about 40 feet along the strike at the base of the outcrop and for about 20 feet up the dip. Insufficient work was done to give an accurate idea of the size of the deposit or to determine if other autunite-bearing beds are present.

Abstract: Approximately 10 square miles of mainly igneous rocks of the western Mojave Desert were covered by this airborne radiometric survey in 173 hours of flying time.

Abstract: "Tests were conducted on a 1:50-scale model of Isabella Dam Spillway to determine the adequacy of proposed spillway, dam, and channel improvements. The model reproduced an area of the reservoir 800 ft wide by 1,100 ft long, the spillway, and the entire length of the exit channel. Unsatisfactory flow conditions were observed in the vicinity of the spillway crest due to approach conditions to the spillway. Large cross waves, present in the exit channel just downstream of the spillway, resulted in occasional overtopping of the right wall. A grouted rock dike that provided satisfactory flow conditions at the spillway and downstream throughout the exit channel was placed adjacent to the existing spillway approach wall."