The Green River Formation in Wyoming, Utah an Colorado is a world-famous Fossil-Lagerstätte known for its spectacular fossil fish, plants, insects, reptiles, birds, and mammals from the Eocene Epoch (56 to 44 million years ago). A Lagerstätte is a sedimentary body yielding an unusual quantity of paleontological information, i.e., a body of rock particularly rich in well-preserved fossil organisms. Many museums, as well as thousands of fossil collectors, around the world have at least one fossil from the Green River Formation in their collections. These fossils made learning about life in and around three large lakes that formed all those years ago in the American west possible.

This book is a well-illustrated and updated guide to the Green River Formation including its geological aspects and its fossils, both fauna and flora. Former quarry owner and paleontologist, Dr. Stefano Piccini, provides and inside look at searching, digging, and preparing Green River fossils, the scientists and commercial fossil hunters doing the work, and exclusive pictures of the most important and rare specimens, some from private collections.