In this last section along the Fabian Ravine, where the best exposures are found, a dating gave 13.21±0.09 Myr (Marrett et al., 1994), which would indicate mid Miocene.These units could be correlated with part of the sequence that emerges on Farallón Catal Island, in which an ignimbrite in the middle section yielded an age of 13 Myr (B. Watson in Alonso and Gutiérrez, 1986, p.43).