Bragg’s plan called for a rapid crossing of the Chickamauga Creek, and one of those crossings should be at Reed’s Bridge by Bushrod Johnson’s Division.

Bragg wanted to get his force over to the west side of the creek, with Johnson crossing at Reed’s Bridge and Walker getting over at Alexander’s Bridge.  He believed that this would put his force north of the Federals, so allowing these units to turn and move south on Rosecran’s army, cutting them off from Chattanooga. Unfortunately for his plans both crossings were held up by the Federals; Minty held up Johnson, while Wilder did the same at Alexander’s Bridge.

Bushrod Johnson’s troops, five infantry brigades supported by Forrest’s cavalry and with eight guns of Robertson’s artillery brigade, were on the Reed’s Bridge road from Ringgold.  Forrest rode with his men, but he also had Pegram’s cavalry division on Johnson’s right to protect them from any troops Granger might send out of Rossville.

Johnson came up against Minty at Peavine Creek, a small stream about a mile east of Reed’s Bridge.

Minty had three regiments as well as a battalion of cavalry and a section of artillery, but he could see he was being overlapped in the north, and dust clouds in the direction of Dyer’s Ford told him more Confederates were on the way. Because of this he called on Wilder to send reinforcements, but the Confederates were strong enough to drive him back over the bridge, too quickly for him to destroy the structure.  Johnson gained the west bank of the creek. Once across Reed’s Bridge the Confederates pushed on to Jay’s Steam Saw Mill, about a mile west of the bridge, then made their left turn to move upstream (south) alond the Jay’s Mill Road towards Walker, who should cross at Alexander’s Bridge.

From Rosecrans’ post battle report

Evidence accumulated during the day of the 18th that the enemy was moving to our left. Minty's cavalry and Wilder's mounted brigade encountered the enemy's cavalry at Reed's and Alexander's Bridges, and toward evening were driven into the Rossville road. At the same time the enemy had been demonstrating for 3 miles up the Chickamauga. Heavy clouds of dust had been observed 3 or 4 miles beyond the Chickamauga, sweeping to the northeast.