Fig. 5 Stratigraphy shown through a section of the crater. The left diagram is based on data from Ramos and Hildebrand and colleagues (1994). The right diagram has been modified in the light of re-examination of the subsurface stratigraphy (11). The main difference is the presence of the breccia across the whole area. Blue=limestone and marl, Yellow=mainly dolomite (a magnesium containing carbonate rock), Green=Evaporite beds with some thiner dolomite units. Names of time periods are defined here.