...ickahominy now divided McClellan's army into two parts. Two of his corps were on the south, and three-Sumner's, Franklin's, and Porter's — on the north side, McClellan's headquarters being at Gaines Mill . The Chickahominy River rises some twelve miles northwest of Richmond, flows in an easterly direction at first, and then takes a southeasterly course, till it empties into the James, some thirty m...