Title: NBG Biozone finding southwestern Cerro Mudadero, Precordillera of La Rioja, Argentina
Abstract: This paper deals with a new record of the Late Carboniferous Nothorhacopteris-Botrychiopsis - Ginkgophyllum Biozone in the Agua de Carlos area (La Rioja Province). The bearing sediments were originally considered Early Carboniferous in age, but the presence of Nothorhacopteris argentinica (Geinitz) Archangelsky and Fedekurtzia argentina (Kurtz) Archangelsky allow us to refer the sequence to the Upper Carboniferous.