For my field trip in Report Writing I choose to go to the Willow Tank Formation in the Valley of FIre State Park in Nevada. This formation is from the early Cretaceous Period around 100 million years old. This formation is related to the Cloverly and Cedar Mountain Formations of the Same age. The Willow Tank consists of a Basal conglomerate with overlying mudrock, sandstone succession of facies. This is separated by a sharp contact. The Willow Tank overlies the Jurassic Aztec sandstone unconformably and is separated by roughly 80 million years. The area represents a fluvial flood plain system with channels sands and flood muds. The basal conglomerate is formed from chert and limestone form the thrusting in the region (Sevier).
The reason I choose this formation was for the vertebrate fossils that it contains. Namely dinosaur fossils analogous to those found in the Cloverly and Cedar Mountain formations. These are important discoveries which can link the Willow Tank to those other formations and which show life a little further inland from the continental sea way. The fossil data recovered here may also link the dinosaurs found in China to a migration into North America. Another example would be the discovery of a tyrannosaurid tooth, representing the earliest of that group yet found in North America.