Abstract Many water samples from wells drilled in the West Texas salt basin were collected during the past 6 years. From the analyses of these samples, a general relation to geologic structure was noted. After careful study of the geologic data from the wells, waters were selected from the first general water horizon of the Permian “Big lime” in that part of the basin in which the upper section of this limestone is fairly consistent and can be correlated with some degree of accuracy. This part of the “Big lime” includes the pay horizons of all of the Permian “Big lime” oil pools thus far discovered in the area. The locations of the water samples are indicated in Figure i, which also shows the concentrations of the individual water samples by lines of equal total solid content. Table I gives descriptions and total solids of the waters from the wells shown in Figure 1. The analyses were calculated according to the system of reacting values proposed by Stabler (1), 3 and the waters were classified according to Palmer’s system (2).