As far as Hazel Grove, at the centre of the bow, Slocum's Twelfth Corps held the line, Geary's division joining on to Couch, and Williams on the right. From Slocum's right to the extreme right of the army, the Eleventh Corps had at first been posted; but Hooker determined on Saturday morning that the line was too thin here, and thrust Birney's division of the Third Corps in between Slocum and Howard. The rest of the Third Corps was in reserve, massed in columns of battalions, in Bullock's clearing, north of the Chancellor house, with its batteries at the fork of the roads leading to the United-States and Ely's Fords. Towards sunset of Friday, Birney had advanced a strong line of skirmishers, and seized a commanding position in his front. Birney's line then lay along the crest facing Scott's Run from Dowdall's to Slocum's right. Pleasonton's cavalry brigade was massed at headquarters, ready for duty at any point. Howard held the line, from Dowdall's Tavern (Melzi Chancellor's) to beyond Talley's farm on the old pike, with his right flank substantially in the air, and with two roads, the main thoroughfares from east to west, striking in on his right, parallel to his position. As will be noticed from the map, the right, being along the pike, was slightly refused from the rest of the line, considering the latter as properly lying along the road to headquarters. From Dowdall's west, the rise along the pike was considerable, and at Talley's the crest was high. The whole corps lay on the watershed of the small tributaries of the Rappahannock and Mattapony Rivers. As a position to resist a southerly attack, it was as good as the Wilderness afforded; although the extreme right rested on no obstacle which superiority in numbers could not overcome. And a heavy force, massed in the clearing at Dowdall's as a point d'appui, was indispensable to safety, inasmuch as the conformation of the ground afforded nothing for this flank to lean upon. Having forfeited the moral superiority gained by his advance, having withdrawn to his intrenchments at Chancellorsville, and decided, after surprising his enemy, upon fighting a defensive battle, Hooker, early on Saturday morning, examined his lines, and made sundry changes in the forces under his command.