In a new model of coal seam formation, advocating the allochthonous process, it has been suggested that the precursor of vitrain was deposited as chemical sediment in a dissolved state derived principally from cellulose segregated from wood tissues. Under acidic conditions, this sediment precipitated as humic acid and continued to float over the aqueous medium. Due to seasonal desiccation of the basin, the floated humic layer, free from contamination of argillaceous impurities, gradually descended and superimposed over the earlier-formed lithotypes. The precursors of durainous lithotypes, in contrast, composed principally of lignin-enriched residual plant cell walls, sticky hydrogen-rich plant ingredients, and agrillaceous dirts, were deposited in the basin as clastic sediments. With a fresh influxof chemical and clastic sediments, the horizontal deposition of basic infrastructures of lithotypes covering an extensive area was repeated, thereby developing the vertical height of the coal seam depicting alternate bands with characteristic affinity to argillaceous impurities.