Presents the results of a fission-track study that discovered an age for the Pretoria Saltpan (Tswaing) impact crater. Usage of impact glass fragments from suevitic breccia of the lower crater fill; Views of sceptics on the impact origin for the cratering event; Usage of the Rb-Sr isotope method to date samples of intrusive rocks from the crater; Findings that suggest that the intrusions in the crater rim are part of a regional magnetic event.