Fence diagram showing lithologic facies of the Sadlerochit Formation (Permian and Lower Triassic), northeastern Alaska

A fence diagram of the Sadlerochit Formation, the major reservoir rock in the Prudhoe Bay oil field, is presented for about 20,000 square miles of northeastern Alaska. Thirty reference points were used in constructing the diagram, 27 are outcrop sections measured in detail between 1969 and 1972, and 4 are well logs of oil wells drilled in recent years.