“…The Dorotea Formation outcropping in the eastern flank of the Río Las Chinas valley comprises 900 to 1200 m thick fossiliferous deposits of sandstones (greenish-gray and reddish-brown), frequent conglomerate and siltstone lenses, thin beds of sandy calcareous concretions and mudstones (Cecioni 1957, Katz 1963, González et al 2015, Manríquez et al 2019) (Figure 2). Along the succession there are several fossil-bearing levels with abundant pteridophytes, gymnosperms, angiosperms, bivalves, gastropods, ammonites, chondrichthyans, anurans, plesiosaurs, mosasaurs, turtles, dinosaurs, and the mammals described here (Katz 1963, Cortés 1964, Soto-Acuña et al 2014, 2016a, b, Schwartz and Graham 2015, Leppe et al 2016, Manríquez et al 2019, Alarcón et al 2020, Trevisan et al 2020) (Figure 2). The fossil-bearing mammal horizon corresponds to sandy mudstone with fine-grained sandstone lenses (Figure 2), interpreted as floodplain facies associated to a meandering fluvial deposit (Manríquez et al 2019).…”