Article

Lignite samples from the mines of Montebamboli and Ribolla (southern Tuscany) are chemical- ly investigated to assess whether they are made up of the fossil species Taxodioxylon gypsaceum, the same morphotaxon of the famous and monospecific Pliocene forest of Dunarobba (Umbria, central ltaly). All the samples contain aromatic hydrocarbons as well as linear and branched alka- nes. In addition. Montebamboli contains traces of cadalene and -phyllocladane while Ribolla contains sesquiterpenes, diterpencs, and de-A-lupane. The presence of aromatic hydrocarbons and alkanes contrasts with the composition of materials of Dunarobba and Santa Barbara (Arno valley) as they contain, almost exclusively. terpenes. The residual terpenes of Montebamboli can only point t0 a generic conifer species while those of Ribolla suggest a blend of conifers and angiosperms since its terpencs do not agree in number and proportion with those of Dunarobba and Santa Barbara. Owing to the great degradation of the materials, shown by pyrolysis gas chro- matography mass spectrometry analysis, cation exchange capacity values and indirect palacob- otany. the original plant material of the two lignites cannot be defined monospecific