The lake and bog deposits of Cedar Creek Forest, Isanti and Anoka counties, Minnesota, consist of a multiple-facies accumulation of marl, peat, copropel, and sapropel. Chromatographic analyses of the lipoid extracts of samples of the sediments show measurable amounts of saturated and aromatic hydrocarbons as well as large proportions of asphalts and polar lipoid compounds. In general composition the “oily” fractions some-what resemble a Venezuelan asphalt. The ratio of total lipoids in the peat, marl, and underlying sand, respectively, in this deposit is approximately 12:3:1. The highest measured content of saturated hydrocarbons occurs just above the marl. The other fractions show no noteworthy relationship to depth or type of material. Most of the variation in distribution of the lipoids appears primary, but some shifting of the hydrocarbons may have resulted from movements of ground water within the bog. The data suggest that the hydrocarbon formation or liberation from the source material took place concomitantly with the accumulation of the lake and bog deposits.