The main rivers of England are not plentiful. No majestic Nile leisurely meanders through arid regions and bountiful plains on its 3,000-mile journey to the ocean; no thunderous Brahmaputra plummets down its inclines, plummeting two or three miles as it spans half of a continent from frigid mountain summits to balmy coast. The largest rivers in England are merely the smallest, trickling creeks in contrast to these. Despite everything, the earth has always valued our small streams greatly. The rivers Tyne, Severn, Humber, Trent, Thames, Mersey, and Ouse, together with numerous other smaller but equally significant streams, have all contributed to the development of England's history and its subsequent rise to commercial prosperity. Valleys have been uplifted to create new highlands, and entire mountain ranges have vanished from view. Large tracts of land have sunk deep enough to let water to flow in and create new seas, while the ocean floor has been propelled up either abruptly or gradually, giving rise to whole new continents. Geology, the study of rocks and the fossils that are buried in them, has taught us everything we know about the planet.