...Union army of occupation, under the command of General G. Granger.--(Doc. 160.) The rebels in the vicinity of Fort Donelson, Tenn., having been gathering all the horses fit for cavalry service, General Rosecrans ordered all the good animals in that neighborhood to be taken by the forces under his command. While engaged in this duty, seventy of his men met an equal number of rebels near Waverly, when a figh...