anning ▁ 2 , 7 0 0 ▁feet ▁in ▁three ▁days . ▁V irt ually ▁all ▁of ▁the ▁Union ▁army , ▁other ▁than ▁elements ▁of ▁the ▁Reserve ▁Corps ▁kept ▁behind ▁to ▁guard ▁the ▁rail road , ▁had ▁safely ▁crossed ▁the ▁river ▁by ▁September ▁ 4 . ▁They ▁faced ▁more ▁mountain ous ▁terrain ▁and ▁road ▁networks ▁that ▁were ▁just ▁as ▁tre acher ous ▁as ▁the ▁ones ▁they ▁had ▁already ▁travers ed . ▁ ▁The ▁Confeder ate ▁high ▁command ▁was ▁concerned ▁about ▁this ▁development ▁and ▁took ▁steps ▁to ▁rein force ▁the ▁Army ▁of ▁Tennessee . ▁General ▁Joseph ▁E . ▁John ston ' s ▁army ▁dispatch ed ▁on ▁loan ▁two ▁weak ▁divisions ▁( about ▁ 9 , 0 0 0 ▁men ) ▁from ▁Mississippi ▁under ▁Maj . ▁Gen . ▁John ▁C . ▁Bre ck in ridge ▁and ▁Maj . ▁Gen . ▁William ▁H . ▁T . ▁Walker ▁by ▁September ▁ 4 , ▁and ▁General ▁Robert ▁E . ▁Lee ▁dispatch ed ▁a ▁corps ▁under ▁L t . ▁Gen . ▁James ▁Long street ▁from ▁the ▁Army ▁of ▁Northern ▁Virginia . ▁Only ▁five ▁brig ades ▁( about ▁ 5 , 0 0 0 ▁effect ives ) ▁from ▁two ▁of ▁Long street ' s ▁divisions ▁arrived ▁in ▁time ▁for ▁the ▁second ▁day ▁of ▁the ▁Battle ▁of ▁Ch ick am aug a ▁on ▁September ▁ 2 0 . ▁ ▁In to ▁Georgia ▁ ▁The ▁three ▁inf antry ▁corps ▁of ▁Rose cr ans ' s ▁army ▁advanced ▁by ▁separate ▁routes , ▁on ▁the ▁only ▁three ▁roads ▁that ▁were ▁suitable ▁for ▁such ▁movements