Previous work has shown some structural similarities between the insoluble organic residues of certain blue-green algae, algal oozes, and kerogens from ancient sediments known to be of algal origin. To obtain more specific structural information on these insoluble organic residues, several specific degradation reactions have been performed on them. This paper describes results from saponifying residues of some blue-green and green algae, two algal oozes, and for the sake of comparison, kerogen from the Green River oil shale. The major aim of these experiments was to obtain information on any compoents linked as esters to the kerogen-like residues. The minor aim was to see whether there were any variations in the saponification products which could be linked to structural variations in the residues.