great urgency of the situation made him resolve upon a bold and almost desperate manœuvre in order to meet the apparent overreaching of our extreme left (Wood's division) by the enemy, viz., the withdrawing of Thomas's corps from the centre and moving it during the evening and night by the rear of Crittenden's corps to its left, and simultaneously shifting McCook's corps to the position vacated by Thomas. The great risk lay in breaking and entirely reversing our line in the face of the enemy, whose onslaught might be expected any moment. The shift was accomplished not entirely, but sufficiently, as events proved, to save the Army of the Cumberland from destruction. Thomas was under way by 4 P.M., and kept in motion all night. His columns had a most toilsome task in finding their way in the dark over narrow cross-roads and through the woods; and although the distance traversed was only between four and five miles, the head, Baird's division, reached its destination at “Kelly's Farm” on Crittenden's left only at daylight on the 19th. This was the very position whose valiant defence by Thomas and his troops during the impending battle was destined to prevent the utter rout of all of Rosecrans's forces.
McCook received his orders to move to the position vacated by Thomas shortly after midnight, and marched at early dawn, with Johnson's division in the lead, followed by Davis's and Sheridan's. He himself reported in person between eight and nine to the Commander-in-chief at Crawfish Springs (about a mile southeast of Lee and Gordon's Mills), and was ordered by him to mass his corps about that point and await further instructions, which was done. Crittenden's corps lay still on the 17th, except that he moved Palmer's division to the left in order to make room for one of Thomas's then approaching.
Between 10 A.M. and noon on the 18th, General Wood sent in several reports that the enemy was advancing on both his left and right, and asked for reinforcement by a brigade. But no collision came from this move on the part
