An analysis of the available geophysical data in the Holbrook basin area of north central Arizona in Coconino, Navajo and Apache Counties has been made. This study has been supported by a contract with the Arizona Oil and Gas Conservation Commission, John Bannister, executive secretary, and the Four Corners Regional Commission. The primary objectives of the analysis were to determine: (1) thicknesses and lithology of sedimentary column overlying Precambrian basement; (2) structural configuration of basement surface, faults in basement and sedimentary rocks; and (3) anomalous conditions within the sedimentary rocks potentially favorable for entrapment of hydrocarbons.