Letrero Formation

The Letrero Formation is a Late Miocene (Mayoan to Montehermosan in the SALMA classification) geologic formation in south-central Ecuador. The formation comprises lacustrine sediments with strong fluvial clastic input and contains siltstones and fine-grained sandstones.^[1]

Letrero Formation
Stratigraphic range: Late Miocene (Mayoan-Montehermosan) ~11.6–5.3 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Type	Geological formation
Lithology
Primary	Siltstone
Other	Sandstone
Location
Coordinates	3.3°S 79.1°W / -3.3; -79.1
Approximate paleocoordinates	3.7°S 77.4°W / -3.7; -77.4
Region	Azuay Province
Country	Ecuador
Extent	Sierra Region
Letrero Formation (Ecuador)

Fossil content

The formation has provided fossils of:

• Anadasypus aequatorianus^[2]
• Caviomorpha indet.
• Litopterna indet.
• Toxodontia indet.

See also

• List of fossiliferous stratigraphic units in Ecuador