Ten samples of drill cuttings from Merrimelia 15 were examined in polished section under normally incident white light and under reflected light UV fluorescence mode. Brief descriptions of the dispersed organic matter contained in each sample, plus descriptions of the rock types and tables of associated vitrinite reflectance values, are given as an adjunct to the main report. This draws together the observations made on the suite of samples and develops an interpretation of the organic petrology in terms of hydrocarbon maturation and the thermal history of the sequence drilled at the location of Merrimelia 15. A close comparison is also made with results from suites of samples previously examined from Merrimelia 6 and Merrimelia 7. The authors discuss vitrinite reflectance vs depth gradients with respect to the stratigraphic position of the oil window in these wells, and compare organic matter types and maturation, local thermal history as reflected by the sediment VR profiles and present well temperatures, and inferred hydrocarbon source potential.