The state of Tocantins has been the subject of several paleontological types of research in the past; however, the Devonian fossils have recently been poorly investigated. This paper expands the knowledge about Devonian in the state of Tocantins, presenting a bibliographic review and adding new fossiliferous discoveries. During fieldwork, brachiopods (Australocoelia, Australospirifer, Derbyina, infaunal lingulids, Orbiculoidea, Tropidoleptus carinatus, Schuchertella), cnidarians (Conularia quichua), crinoids (Exaesiodiscus dimerocrinosus, Laudonomphalus, Monstrocrinus), mollusks (Platyceras, Nuculites, Palaeoneilo, Sanguinolites), and plants remains (Spongiophyton lenticularis) were found in different sedimentary facies of the Pimenteira Formation

A taxonomic review of Miocene gastropods from the Solimões Formation, Acre Basin, Brazil, from specimens collected at Cachoeira do Bandeira, Oriente, and an outcrop named Spot 04, is here presented. Three ampullariid species (Pomacea maculata, P.planorbula, Pomacea sp.), one thiarid species (Aylacostoma sp.), and one cochliopid species (Sioliella sp.) are identified for these deposits. These gastropod are known to occur in freshwaters environments, thus consolidating the hypothesis of a non-influence of brackish water on the upper Miocene deposits of the Acre Basin. The previous identification of P. maculata and Aylacostoma sp. is changed here considering biometrical analyses and shell morphological descriptions. The first report of Sioliella in this basin increases the gastropod fauna known for these strata and expands the range of this genus. Keywords: Pomacea, Aylacostoma, Sioliella, Ampullariidae, Thiaridae, Cochliopidae.