Carbonaceous material from several boreholes which penetrated the Carboniferous strata in the Zemplinicum block is according to reflectance and DT A characteristics at the meta-anthracitic stage. X-ray diffraction corresponds to a less ordered structure typical of anthracite what is supposed to be a result of high concentrations of intertinite in the samples. The analyses of carbonaceous material give evidence that the sedimentary rocks were exposed to very low-grade/low-grade metamorphism under high-temperature and low-pressure conditions, probably during the latest Paleozoic and the early Mesozoic periods. Discontinuities in graphitization with depth suggest postmetamorphic faulting and overthrusting of the partial blocks of the sequence.