Figure 18. Geologic map of the caldera floor and intracaldera Caetano Tuff near Caetano Ranch (Wenban Spring 7-' quadrangle). The caldera floor, which is exposed for 4 km along strike, consists of Permian-Pennsylvanian Antler overlap sequence limestone and conglomerate (Fig. 4A), overlain by andesite lavas. The lower unit of intracaldera Caetano Tuff, as much as 3.6 km thick, overlies the pre-caldera rocks. The upper unit of Caetano Tuff including mesobreccia crops out on the downthrown side of the middle Miocene Caetano Ranch Fault. Paleozoic Valmy Formation south of the Wenban Fault constitutes the southern caldera wall.