High performance liquid chromatography (HPLC) on normal phase has been performed on sedimentary rocks and crude petroleums to obtain fingerprints on polycyclic aromatic hydrocarbons (PAH) separated by degree of aromaticity. Chromatographic fractions containing methylphenanthrenes (MP) and methylchrysenes (MC) have been collected to obtain the relative distribution of these isomers by capillary gas chromatography (GC) and/or high resolution spectrofluorimetry (HRS). Trends in the distribution are tentatively correlated with the maturity of the studied samples.