# Javelina Formation

The Javelina Formation is a geological formation in Texas. Dating has shown that the strata date to the Maastrichtian stage of the Late Cretaceous, approximately 70 to 66.5 million years old. The middle part of the formation has been dated to about 69 million years ago plus or minus 1 million years and the top situated near the Cretaceous–Paleogene boundary (in the overlying Black Peaks Formation), dated to 66 Ma ago. Dinosaur remains are among the fossils that have been recovered from the formation.

## Age

The typical age range of the Javelina Formation has been difficult to determine. Only one geological site in the Javelina Formation has thus far yielded the correct rock types for radiometric dating. The outcrop, situated in the middle strata of the formation about 90 meters below the K-Pg boundary and within the local range of Alamosaurus fossils and below two sites that have yielded Quetzalcoatlus fossils, was dated to 69.0 plus or minus 0.9 million years old in 2010. Indeterminate chasmosaurinae fossils have also been as well.

## Fossil content
### Vertebrate paleofauna

Vertebrates of the Javelina Formation :
| Genus | Species | Notes |
| Alamosaurus | A. sanjuanensis | A titanosaurian sauropod, also from the Ojo Alamo Formation |
| Bravoceratops | B. polyphemus | A chasmosaurine ceratopsid known from the lowermost part of the Javelina Formation which dates back to the early Maastrichtian. |
| Dasyatis | Unknown | A ray |
| Gryposaurus? | G.? alsatei | A saurolophine hadrosaurid known from the Two Medicine Formation, the Dinosaur Park Formation, the Kaiparowits Formation, possible remains have also been unearthed in the El Picacho Formation. |
| Kritosaurus | K. cf. navajovius | A saurolophine handrosaurid, also known from the Kirtland Formation, Aguja Formation, Ojo Alamo Formation and the El Picacho Formation. A possible second species of Kritosaurus might have lived in the Javelina Formation. Fossils have also been unearthed in the Olmos Formation. |
| Quetzalcoatlus | Q. northropi and Q. lawsoni | An azhdarchid pterosaur |
| Rhombodus | Unknown | A ray |
| Saurornitholestes | S. cf. langstoni | A dromaeosaurid |
| Saurolophinae | Indeterminate | A saurolophine handrosaurid similar to the genus Saurolophus. |
| Torosaurus | T. cf. utahensis | A chasmosaurine ceratopsid whose remains have been found in the Frenchman Formation, Hell Creek Formation, North Horn Formation, McRae Formation, and Lance Formation. |
| Troodontidae | Indeterminate | A troodontid |
| cf. Tyrannosaurus | Indeterminate | A tyrannosaurid, originally identified from the Hell Creek Formation. Also found in the Denver, Ferris, Frenchman, Lance, Livingston, North Horn, Scollard, and Willow Creek Formations. |
| Trionychidae | Indeterminate | Indeterminate turtle remains |
| Wellnhopterus | W. brevirostris | An azhdarchid pterosaur. |

### Flora

Woody dicots and angiosperms have been unearthed in this formation. Plant fossils indicate that this area was a woodland habitat.
Flora of the Javelina Formation :
| Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
| Javelinoxylon | J. multiporosum | | | | A dicotyledonous tree | |