The circular structural depression here described is one of at least two extraordinary “sinks,” 2½ to 3 miles in diameter, found in central Kansas. Its center is near the middle of sec. 28, T. 16 S., R. 4 E., in Dickinson County, Kansas, 4 miles southwest of Herington. Another similar “sink” has its center near the middle of the east line of sec. 20, T. 15 S., R. 5 E., in Morris County, about 9 miles northeast of the one here described. These two “sinks” appear to differ only in that the northeastern one is somewhat elliptical in outline, being slightly longer from north to south instead of round.
The surface rocks of the region include the Permian limestones called the Herington lime and the Pearl lime, which are well exposed near the “sinks” and provide good control for structural mapping. The structural depressions are only weakly reflected in . . .