Figure 8. Photographs showing aspects of the upper unit of the Caetano Tuff. (A) View east of prominent cooling break between lower (Tcl) and upper (Tcu) units of Caetano Tuff along west side of ridgeline 2 km south of Rocky Pass. Low hills in foreground composed of middle Miocene sedimentary rocks (Ts) deposited in hanging wall of the Miocene Rocky Pass fault. Ridgeline is 300 m above valley floor. (B) Hydrothermally altered volcaniclastic sandstone and pebble conglomerate beds in upper unit of Caetano Tuff on south side of Wilson Canyon near Redrock Canyon. White recessively weathered beds are kaolinite altered, whereas dark resistant beds are silicified. (C) View north of multiple fault blocks of the upper unit of the Caetano Tuff (Tcu) in the low hills southeast of Rocky Pass and Paleozoic rocks (Pz) forming skyline in the Shoshone Range. White rocks on valley floor are syn-extensional, middle Miocene sedimentary rocks (Ts) that unconformably overlie the caldera (Colgan et al., 2008). Dips of these sedimentary rocks shallow upward to the east (Plate 1). Densely welded outflow Caetano Tuff crops out in the foreground. (D) Block of densely welded lower Caetano Tuff (Tcl) in lithic-rich poorly welded lower part of upper Caetano Tuff (Tcu) northwest of Tub Spring. Hammer handle is 55 cm long.