1. Geologic map showing the Oligocene rhyolite canyon tuff in part of the Bruno Peak quadrangle, southeastern Arizona Yale Public content 1995. 2002-06-01T04:00:00Z. 2002-06-01T04:00:00Z. Geological Survey (U.S.). The Survey ; For sale by Information Services. English. Public. Arizona and Cochise County. Oligocene.