From Mississippi
Morton, Miss., Aug. 1.
--A large number of the chiefs and braves of the Choctaw tribe passed through here yesterday on the way to visit the Great Father at Richmond.
Grant has established a garrison of about 3,000 men at Natchez.
Wirt Adams's scouts bring intelligence that Banks attacked Dick Taylor at Donaldsonville on the 23d ult, and was defeated, with a loss of 6,000, including 4,000 prisoners; and that Taylor's and Magruder's forces have since united on the Teche river, which, if true, will enable Taylor to place in position the seige guns captured at Thibodaux, and blockade the river below.
[Second Despatch]
Morton, Aug. 3
--The latest advices from the Mississippi river represent the river as swarming with gunboats and transports above Vicksburg.
Eight gunboats and ten transports were counted between Vicksburg and Natchez last Friday.
This does not prevent communication with the trans Mississippi Department.
Accounts from that side are cheering, but contraband.
The enemy have placed a garrison of 2,500 men at New Carthage.
Logan is watching their movements, the enemy will hear from him soon.
No troops have gone up the river, save McPherson's corps and part of Burnside's command.