George Stoneman
George Stoneman, Jr. was a United States Army cavalry officer, trained at West Point, where his roommate was Stonewall Jackson. In the Civil War, he became Adjutant to George B. McClellan, who did not appreciate the use of centralized cavalry, and was therefore outperformed by the Confederates, who did.
Stoneman was born on a family farm in Busti, New York, the first child of ten. His parents were George Stoneman, Sr., a lumberman and justice of the peace, and Catherine Rebecca Cheney. He studied at the Jamestown Academy and graduated from the United States Military Academy in 1846 his roommate at West Point was future Confederate General Thomas J. Stonewall Jackson. His first assignment was with the 1st U.S. Dragoons, with which he served across the West and in California. He was the quartermaster of the Mormon Battalion, which marched from Fort Leavenworth, Kansas, to San Diego, California. He fought in the Yuma War and was responsible for survey parties mapping the Sierra Nevada range for railroad lines. After promotion to captain of the 2nd U.S. Cavalry in March 1855, he served mainly in Texas until 1861.
Source: Wikipedia