Figure 10. Structural contour map, on top of pre-Pennsylvanian strata, at Cushing field, south of the Jennings feature and on the same Whitetail strike-slip fault trend (modified from Weirich, 1929). It is a high relief, pop-up structure with essentially the same history as the Oklahoma City, Garber, and El Dorado structures, and with Middle Pennsylvanian strata overlying deeply eroded Arbuckle on its crest. It should be noted that in 1929, when this map was published, geologists did not recognize the role of high-angle faults.