Analyses of Deep Sea Drilling Project Cores 5 and 6, Leg 1, Site 2 indicate that a bona fide crude oil exists in the Challenger Knoll in a normal cap rock environment. These conclusions are based upon oil composition, rock characteristics and isotopic data.The lithology of Core 5 is calcite at the top with calcite and sulfur at the base. Material recovered in Core 6 is gypsum. The calcite portion of Core 5 contains a low gravity, high sulfur oil which is highly aromatic and highly asphaltic-consistent with other low gravity petroleums. The known Gulf Coast Tertiary crude oils with high sulfur appear to be associated with salt dome cap rock. The Challenger Knoll oil has some unusual characteristics which, however, are shared by some known cap rock oils produced from the Gulf Coast Tertiary. Some unusual deficiencies in n-paraffins occur in the liquid petroleum gas and the virgin naphthas. The C 4 , C 5 , C 6 and C 7 hydrocarbons are deficient in nparaffins relative to the corresponding isomers. The profile of the C 7 hydrocarbons as a percentage of C 7 saturates in the Challenger Knoll oil is similar to that in known Tertiary cap rock oils from the Spindletop and Stratton Ridge fields produced from Gulf Coast Tertiary sediments.