Dos Bocas Formation

The Dos Bocas Formation is a Chattian, about 26 to 24 Ma, (Deseadan in the SALMA classification) geologic formation of the Progreso Basin in southwestern Ecuador.
Description.
The formation comprises moderately-sorted, fine to medium sandstones with angular quartz-feldspathic clasts. Conspicuous rounded green grains are probably glauconite, but berthierine cannot be dismissed. The matrix is micritic and volcanogenic, possibly bentonitic. The formation was deposited in an estuarine to mid shelf environment. Fossils of sharks, turtles and the tropical "Urkudelphis" were recovered from the formation.
Fossil content.
The formation has provided fossils of: