These four drills were just a few of those collected from an American Indian camp site in Elk County and donated to the Kansas Historical Society in 1972 and 1975, by the same donor. All of the drills may have been modified (reworked) from other chipped stone tools. Two drills get their pinkish color as a result of the material being carefully heated before manufacturing to improve the chert's knapping qualities. Drills were used to bore holes in softer material than the drill itself, such as hides, shell, wood, or soft stone.