This research was partly funded by GSA student research grant #7298-02 to Pieter Vermeesch. Well cuttings were provided by William Bazeley and ARCO Inc. Vitrinite reflectance analysis was performed by Clark Geological Services and supported by the Stanford Petroleum Geology Industrial Affiliates program (``San Joaquin Project''). Zircon fission track measurements were performed by Paul F. Green of Geotrack International Pty. Ltd. We want to thank Trevor Dumitru for suggestions and help with the apatite fission track dating, Kathy Surpless for discussions and sharing mineral separates, Bob Coleman for discussions and field assistance, and Bill Dickinson and Paul O'Sullivan for useful and insightful reviews.