101 cuttings and 14 core samples from the depth interval 7500-10,485 feet KB were analysed both to assess the hydrocarbon source potential (maturity, richness, quality) of the Early Cretaceous Pretty Hill Sandstone, and to determine the biomarker geochemistry of the Pretty Hill reservoir bitumen for comparison with that of coastal bitumens washed ashore from submarine oil seeps in the western Otway Basin. The findings were as follows: (1) the majority of samples examined contain fair to good amounts of gas- prone Type III kerogen; (2) mature oil and gas-prone shales of fair to very good source richness appear to be confined to only two intervals, 8100-8700 feet and 9300-9400 feet KB; (3) all three reservoir bitumens isolated for biomarker analysis have an aromatic-asphaltic bulk composition and appear to be heavily biodegraded; (4) the bitumens appear to contain hydrocarbons from at least two different episodes of oil migration into the Pretty Hill Sandstone; (5) like the four families of coastal bitumen so far identified in the western Otway Basin, the Crayfish A-1 reservoir bitumens contain the source-specific lacustrine algal biomarker, C34-botryococcane. However, differences in their sterane and hopane distributions and their distinctive carbon isotopic composition suggest that these reservoir bitumens may represent tar mat residues of two additional oil families; (6) neither the reservoir bitumens nor any of the coastal bitumens were sourced by the organic facies of the Pretty Hill Sandstone present in the Crayfish A-1 well section.