A knowledge of the quantity and nature of the organic matter in the Cooper/Eromanga Basin sequences is essential in order to evaluate source rock potential. It is possible to set up a data collection system which is relatively free from assumptions concerning the distribution of the various components to liquids and gas generation. The data can then be used to evaluate the contribution to generation made by various components. In a similar way the effects of the distribution and associations of the organic matter on migration efficiency can be assessed. Point count methods have relatively low precision for rare components and can provide information on association only if relatively cumbersome combination analyses are used. The evaluation of source rocks involves a great number of factors but if too many categories are distinguished the use of the data becomes mathematically very cumbersome and visual checking of data trends becomes impossible. The analytical method proposed involves the separate recognition of organic matter occurring as coal, shaly coal and dispersed organic matter (dom). The dom is further divided into six abundance categories. Source rock potential is evaluated by reporting the percentages of coal, shaly coal and the three most abundant dom categories. Data are reported for each maceral group separately and for total organic matter.