Cloverly Formation

The Cloverly Formation is a geological layer in the Big Horn Basin in Wyoming made up of clay and sandstone deposits. The layers show distinct color variations from gray to reddish and contain many fossil remains from past eras.

The layer was first scientifically described in 1904 and named after a nearby post office located in the eastern part of the Big Horn Basin. This name helped geologists identify the formation clearly in their research.

The formation is known for its Early Cretaceous fossils, especially dinosaurs like Deinonychus and Tenontosaurus, which visitors can see in nearby museums. These remains tell the story of life in an ancient landscape millions of years ago.

The area is remote and requires careful planning for a visit, as there are few marked trails and facilities in the region. Visitors should bring local maps or ask for advice locally to find the best access points.

The mudstone deposits here preserve clues about different environments from about 120 million years ago, including traces of river settings and drier land areas. This variety of environments in a single layer is rare and gives researchers valuable insights into ancient ecosystems.