The qualitative petroleum potential map displays the digital data sets used to outline four areas of petroleum potential. On the map we display the outlines of calderas (from Ludington and others, 1996), the rock units we considered to have very low-to-no potential (plutonic rocks, Mesoproterozoic and Paleoproterozoic metamorphic and granitic rocks, and metamorphic core complexes), and petroleum exploration wells (shows and no shows or no data). We also show the conodont coloration index (CAI) data, and the organic maturity data (or absence of data) in oil wells (Hess, 1992).