An assemblage of four silicified woods from the Neuquén Group (Upper Cretaceous) collected in the Cara Cura Mountain Range, southwest of Mendoza Province, Argentina is described. The specimens are composed of secondary xylem, and the preservation varies among them. Two specimens were assigned to Agathoxylon antarcticum (Poole et Cantrill) Pujana et al., related to Araucariaceae. This fossil-species is characterized by its distinct growth ring boundaries, uni- to biseriate araucarian pitting on tracheid radial walls, and araucarioid cross-fields. Other specimens could not be assigned to a fossil-genus because of their poor preservation, but they show a conifer anatomy. The distinct growth ring boundaries of some specimens suggest annual seasonality. Additionally, the presence of small globose structures in areas of highly degraded secondary xylem is consistent with the erosion bacteria type observed in modern and fossil woods.