| Image at top is a view northward from State Route 190 a few miles west of Towne Pass to colorful Tertiary-age volcanics and tuffs in the Panamint Range; at bottom, the jeep is parked along the rugged, primitive trail to the Big Four Mine along the western side of the Panamint Range, east of Panamint Valley: the view is eastward. Between 1944 and 1952, miners at the Big Four Mine exploited localized rich concentrations of lead-zinc ores in hydrothermally altered Paleozoic Era carbonates of the Upper Pennsylvanian Keeler Canyon Formation, whose thin-bedded limestones can be seen along the slopes in the foreground, immediately behind the jeep sitting along the gravel "road." The Keeler Canyon Formation produces abundant small fusulinids, an extinct single-celled organism that constructed a distinctive wheat to football-shaped shell. |