The Definitive Journals of Lewis and Clark, Vol 7Since the time of Columbus, explorers dreamed of a water passage across the North American continent. President Thomas Jefferson shared this dream. He conceived the Corps of Discovery to travel up the Missouri River to the Rocky Mountains and westward along possible river routes to the Pacific Ocean. Meriwether Lewis and William Clark led this expedition of 18046. Along the way they filled hundreds of notebook pages with observations of the geography,