Aguja Formation


The Aguja Formation is a geological formation in North America, exposed in Texas, United States and Chihuahua and Coahuila in Mexico, whose strata date back to the Late Cretaceous. Dinosaur remains are among the fossils that have been recovered from the formation.

Age

The ages of the Aguja Formation and its primary fossil-bearing unit, the Upper Shale, are not well understood. Two radiometric dates have been taken from different sections of the upper shale, yielding ages of 72.6 Ma +/- 1.5 Ma old, and 76.9 Ma +/- 1.2 Ma old, respectively. The contact with the overlying Javelina Formation has been estimated at about 70 Ma ago but also as recently as 68.5 million years ago. The base of the entire Aguja Formation has been estimated at about 80.5 million years old.

Invertebrate paleofauna

Ammonites

Vertebrate paleofauna

Crurotarsans

Ornithischians

Saurischians

Indeterminate ornithomimid remains are known from the Upper Aguja Formation. Indeterminate tyrannosaurid fossils are known from the Upper Aguja Formation of Texas and Mexico.

Turtles