Retene and methylretene have been identified by gas chromatography-mass spe
ctrometry in aromatic hydrocarbon fractions of Silurian carbonate extracts
of the Michigan Basin, Retene identified in pre-Devonian carbonates indicat
es that the compound not only is the biomarker of higher plants but also de
rived from alga or bacterium. The geochemical significance of methylretene
has been discussed.