Hydrocarbon gas concentrations (µL/L of wet sediment) obtained from extraction of samples collected on Leg 164 are listed in Table 2 and Table 3. The following hydrocarbon gases are reported: methane (C1), ethane (C2), ethene (C2=), propane (C3), propene (C3=), isobutane (iC4), n-butane (n-C4), neopentane (neoC5), isopentane (iC5), n-pentane (n-C5), cyclopentane (cycloC5), neohexane (neoC6), isohexane (iC6), n-hexane (n-C6), isoheptane (iC7), and methylcyclohexane + n-heptane (methylcycloC6 + n-C7). In addition, the ratio C1/(C2 + C3) is given in Table 2 and Table 3. The concentrations of gases obtained by the procedures used here are method and time dependent. That is, the concentrations represent the residual gas present after the samples have been recovered from the cores and stored. The samples have undoubtedly outgassed during core recovery. Length of time taken in sampling will affect the amount of gas that is eventually measured. Consequently, the reported concentrations are referred to as "residual." In situ concentrations of gases can only be obtained through the use of pressure-core samplers (Dickens et al., 1997).