[1] Originally thought to be Campanian (c.73-72 million years ago) in age or earlier, studies of underlying formations have made a Maastrichtian (72–66 million years ago) age more likely.

[2] It is divided up into three distinct facies, the first is up to 16 metres (52 ft) thick and consists of conglomerate, the second is by far the thickest at over 100 metres (330 ft), consists of siltstone and claystone, with interbeds of claystone/shale and sandstone, the third is less than 10 metres (33 ft) thick and consists of clay, and probably represents a nearshore marine environment.

However, recent paleobotanical discoveries at the Cañadón del Irupé locality have revealed the presence of a more diverse range of plants associated with these water bodies, including pteridophytes, gymnosperms, and various angiosperms.

[4] Over 300 mammal specimens have been found in the La Colonia Formation.

[17] Fossils of madtsoiids, and perhaps boids, have been found in the formation.