The Seca Formation is a Late Eocene (Divisaderan to Tinguirirican in the SALMA classification) geologic formation of the Progreso Basin in southwestern Ecuador. The shales of the formation have provided fossils of the marine snake Pterosphenus sheppardi, P.shepardi is the only species of the genus in South America .Ancón at Fossilworks.org
Description The Seca Formation, part of the Ancón Group, conformably overlies the Socorro Formation and is overlain by the Punta Ancón Formation. The Seca Formation comprises grey to greenish shales deposited in a marine platform with submarine fans environment.Lorenzo et al., 2018, p.34 The formation is a reservoir rock,Lorenzo et al., 2018, p.32 and potential source rock,Lorenzo et al., 2018, p.31 in the oil-rich Progreso Basin.
See also List of fossiliferous stratigraphic units in Ecuador
References
Bibliography
Further reading R. Hoffstetter. 1958. Un serpent marin du genre Pterosphenus (Pt. Sheppardi nov. sp.) dans L’Éocène supérieur de L’Équateur (Amérique de Sud). Bulletin de la Société Géologique de France 6:45-50