The New International Encyclopædia/Laramie Stage

LARAMIE STAGE. A geological formation of Western North America, constituting a transition between the marine deposits of the Cretaceous and the fresh-water strata of the Tertiary system. It is now generally classed with the Cretaceous. The Laramie rocks comprise sandstones, conglomerates, and clays, with a thickness of several thousand feet, outcropping along the eastern border of the Rocky Mountains from Mexico northward across the United States into Canada. The formation is of great economical importance, owing to the included deposits of coal. Much of the coal mined in Colorado, Wyoming, Montana, and New Mexico is of Laramie age. The fossils include fresh and brackish water mollusks, land plants, and many species of reptiles; among the reptiles are Plesiosaurus, Claosaurus, and Ceratops. Consult White, “Correlation Papers—Cretaceous,” United States Geological Survey Bulletin 82 (Washington, 1891). See Cretaceous System.