Determinations of the velocity of elastic waves in the Tishomingo granite and Arbuckle limestone were made by seismic methods. The measurements on the granite were taken over both long and short spans in the same area, the former including distances of 500 to 2,500 feet, the latter, distances of 5 to 400 feet. Due to unusual precautions, the short-span data are accurate to 2 per cent. The long-span data give a straight line time-distance graph within observational errors and yield a value of 17,950 ft./sec. for the longitudinal wave velocity. The data taken over the shorter span show a definite curvature in the time-distance graphs, the longitudinal velocity varying from 14,880 to 17,150 feet per second, and the transverse velocity from 7,000 to 7,950 ft./sec. From these ata the elastic constants of granite are calculated. Laboratory measurements were made on two small rods of granite from the same locality, by a method giving results accurate to less than 1 per cent. The velocities so obtained were somewhat higher. Velocity measurements were made along and across the bedding plane of Arbuckle limestone in a region where the dip of the bed approaches 90°. The velocity along the bedding plane was 17,400 feet per second and across the bedding plane 13,400 feet per second.