McCook's corps of three divisions had crossed two difficult ridges--Sand and Lookout mountains--to Alpine in Broomtown Valley with intentions against Summerville.

Thomas's corps had marched by the way of Stevens's Gap toward Lafayette, which he expected to occupy.

Crittenden had passed through Chattanooga, at first directing his march an Ringgold.

Thus the corps of the army were not in conjunction, and between McCook and Thomas there intervened a positive and aggressive obstacle in the shape of Bragg's army concentrating and awaiting reinforcement at Lafayette.

Under these circumstances Bragg could have taken the different corps in detail, and it is strange that he did not, even before receiving his reinforcements, turn on McCook in Broomtown Valley and destroy him.
Intelligence that Bragg would give battle began to come to us from various sources as early as the 10th of September, and on the 11th McCook found that he could not communicate with Thomas by the direct road through Broomtown Valley; but we did not begin closing in toward Chattanooga till the 13th, and even then the Twentieth Corps had before it the certainty of many delays that must necessarily result from the circuitous and difficult mountain roads which we would be obliged to follow.