Javelina Formation

The Javelina Formation is a geological sequence exposed in Big Bend National Park that consists of alternating layers of sandstone and mudstone. These deposits display characteristic purple and gray coloring that marks different phases of geological development.

This sequence formed during the Late Cretaceous period, with the middle section dated to approximately 69 million years ago. The deposits accumulated during a time span that marks the end of the dinosaur age.

The formation contains numerous fossil remains, including bones from Alamosaurus, Tyrannosaurus, Edmontosaurus, and the pterosaur Quetzalcoatlus.

The formation is accessible via designated roads and hiking trails throughout the park, where various outcrops can be examined. Visitors should bring plenty of water and sturdy footwear, as the terrain is dry and rocky.

The deposits contain fossil bones from large plant-eating and meat-eating dinosaurs, revealing that this area was once a fertile river valley. Remains of flying reptiles have also been found here, indicating that different animal species inhabited this region together.

Location: Texas

GPS coordinates: 29.30000,-103.40000

Latest update: December 10, 2025 15:52