Figure 12. Geologic map of the southern caldera margin at Red Mountain (Wood Spring Canyon 7-' quadrangle). East-dipping Caetano Tuff and interbedded mesobreccia lenses composed of Paleozoic clasts (Fig. 13A) are abruptly truncated against Paleozoic Valmy Formation at west-northwest–striking, steeply north-dipping caldera margin. Upper mesobreccia consists of interbedded lenses of Paleozoic clast debris-flow deposits and lithic-rich Caetano Tuff (Fig. 13B). The Red Mountain fault steps abruptly westward at and probably reactivates the caldera boundary fault.