Vast rolling prairies, cut by many creeks and rivers, make up the landscape in northwestern Kansas. It is a land rich with prehistoric history, as seen in fossils left by inland seas that once covered the plains. Several state parks and museums are located in this region of the state. It includes Cheyenne, Rawlins, Decatur, Norton, Sherman, Thomas, Sheridan, Graham, Wallace, Logan, Gove, and Trego counties.