The engagement was furious; commencing on the rebel right, it extended to the left, until it reached the Peach Orchard, where it became especially violent.

This central point of Sickles' line was held by eleven regiments of Birney's and Humphreys' divisions.

Birney's two brigades, commanded by Graham and De Trobriand, held on bravely, for the men who fought with Kearney in the Peninsula were not easily driven; but the line was too attenuated to resist the shock very long, and reinforcements became absolutely necessary to sustain that unlucky angle at the Peach Orchard.

Sickles had authority to call on Sykes, whose corps was resting from a long and fatiguing march, but the latter wished his men to get their coffee and be refreshed before sending them in; and as those who are fighting almost always exaggerate the necessity for immediate reinforcements, Sykes thought Sickles could hold on a while longer, and did not respond to the call for three- quarters of an hour.
It would seem that Lee supposed that Meade's main line of battle was on the Emmetsburg pike, and that the flank rested on the Peach Orchard, for he ordered Longstreet to form Hood's division perpendicular to that road, whereas Sickles occupied an advanced line, and Sykes the main line in rear.

McLaws says that Lee thought turning the Peach Orchard was turning the Union left.