It was felt that General Bragg had one advantage--he could see without being seen. His scouts were on the top of Pigeon Mountain, and they watched every movement of the Union troops, while the Confederates lay concealed behind the thick growth of timber along the Chickamauga. The most Rosecrans could do was to keep his cavalry in motion, reporting every movement the instant it was developed in front of the Army of the Cumberland. Bragg had concentrated his forces, and now he planned to strike one tremendous blow at a flank of the Union forces, and gain Rosecrans' rear and his line of communication with his depot of supplies. For this purpose the Confederate leader divided his forces into two corps, one under Polk and the other under Longstreet, Hood commanding the latter temporarily. The troops advanced in the darkness, and by midnight held all the fords of the Chickamauga from Lee and Gordon's Mill well toward Missionary Ridge. But meanwhile, the Army of the Cumberland was not idle. Crittenden was on the left, and Bragg was going to strike him. By a forced march along the Dry Valley road during the night, Thomas with his entire corps, and followed by a portion of McCook's corps, reached a position facing the Reed and Alexandria bridges, now burned,--thus making the left wing of our army virtually the right wing. And not only did Thomas do this, but without waiting for Bragg to attack, or recover from his surprise, he forced the battle by trying to capture a Confederate brigade said to have become isolated from the balance of its command. This was the opening of the great battle. To go into the details of this contest would require volumes. Accounts without number have been written, yet the tale is far from complete. Of the fighting, let it be said briefly that it covered miles of territory thickly overgrown with timber and crossed and recrossed by numerous creeks and brooks, with here and there a rocky elevation or a stretch of marsh land. In these thickets whole divisions became separated from their comrades in arms, and often a single regiment on one side would be found fighting a regiment on the other side, totally ignorant of what was going on around them. It was almost impossible to move the artillery around, and when pieces were captured they were generally found to be "white elephants" upon the victor's hands.