On September 22, 1951, Marc Navarrete brought word to the Arizona State Museum of the discovery of two large projectile points in association with mammoth bones exposed in an arroyo eroded by Greenbush Creek one mile northwest of Naco, Arizona (Fig. 1). Marc Navarrete and his father, Fred, for some fifteen years have been watching the arroyo for fossils as erosion widened and deepened it.
A bone concentration, though known for some time, was freshly exposed by floods resulting from heavy summer rains in August, 1951. This encouraged Fred Navarrete to dig in an attempt to salvage what appeared to be a part of a skull with teeth and tusk of a large animal. In the course of this work he found near the skull a projectile point in what appeared to be undisturbed matrix. Additional excavations by Marc Navarrete soon revealed the left foreleg, scapula, humerus, and ulna and, near the superior margin of the scapula, again in the undisturbed clay, a second projectile point came to light.