The work here presented deals specifically with the palynological analysis of greyish sandstones considered as belonging to the "Barreiras Group", that occur near Marabá, State of Pará. The study of these sediments revealed the presence of an abundant and Lower Cretaceous microflora. The species identified permit the precise establishment of an Aptian age for the sandstones. The depositional environment, inferred from the fossil content, is interpreted as continental, possibly fluvio-lacustrine.
