George Horatio Derby was a soldier cartographer humorist engineer and practical joker. He surveyed the Sacramento Valley the Tulare Valley San Diego Harbor the mouth of the Colorado River. His humor concepts were used and expanded by Mark Twain. He knew and interacted with General Winfield ScottRobert E. Lee Ulysses S. Grant and William Tecumseh Sherman. He was a classmate of George Pickett George McClellan and Stonewall Jackson.