The distributions of residual hydrocarbon gases correlate well with the record of sulfate depletion in the upper ~60 m of sediment at each site reported here. In the lower stratigraphic intervals, especially in the intervals where gas hydrate was recovered and where chemical, thermal, and logging data indicated disseminated gas hydrate, the measured residual gas concentrations did not reflect anomalously high amounts of methane indicative of the presence of gas hydrate. Also, the free-gas interval beneath the gas-hydrate zone was not clearly revealed. The residual-gas method employed here and the method used shipboard (Paull, Matsumoto, Wallace, et al., 1996) are not adequate to yield even qualitative, proxy information concerning the in situ hydrocarbon gas concentrations and distributions below the zone of sulfate reduction and early methane production. However, the molecular and isotopic compositions of residual gases collected by the methods described here permit interpretations of hydrocarbon gas sources and processes affecting these gases. To understand the true distribution and concentration of hydrocarbon gases in oceanic sediments will require the use of pressure-core-samplers (Dickens et al., 1997), but because of difficult deployment logistics, these kinds of samplers currently can only provide a spotty record. Improvements in pressure-core-sampling technology and strategy are required.