On July 27–29, the Army of the Potomac's II Corps under Maj. Gen. Winfield S. Hancock and cavalry under Maj. Gen. Philip Sheridan attacked New Market Heights and Fussell's Mill in the First Battle of Deep Bottom (named for the section of the James River used for the Union crossing). The attacks failed to break through to threaten Richmond or its railroads, but they did cause Confederate Gen. Robert E. Lee to transfer men from the Petersburg fortifications in preparation for the Battle of the Crater on July 31. The Second Battle of Deep Bottom was conducted by Hancock on August 14–20, attacking in almost the same areas once again to draw Confederate troops away from south of the James, where the Battle of Globe Tavern (also known as the Second Battle of the Weldon Railroad) was an attempt to cut the railroad supply lines to Petersburg. The second battle was also a Confederate victory, but it forced Lee to weaken his Petersburg defenses and abandon plans to reinforce his men in the Shenandoah Valley.