Two samples of Type II kerogen-rich cuttings from the depth interval 5780- 5800 feet were submitted to solvent extraction and detailed GC-MS analysis, initially to determine the biomarker distributions of the shale extracts and then to compare their biomarker geochemistry as examples of Early Cretaceous ?lacustrine shales with that of Otway Basin coastal bitumens previously investigated. The ratios of biomarker parameters demonstrate that the basal Pretty Hill shale is too immature to be an effective source rock for oil at the Robertson 1 locality. However, geochemical similarities with coastal bitumens are still identifiable in terms of recognizing precursor biota and depositional environment. The shale extracts appear to bear little resemblance to the Family 1 coastal bitumens in which botryococcane is especially abundant, but instead their source-diagnostic features attest to a ?freshwater algal source affinity not unlike that of the Family 2 and 3 bitumens. In this regard the presence of biochemical markers of dinoflagellates is of particular environmental significance.