Longstreet's attack was delayed, however, because he first had to wait for his final brigade (Evander M. Law's, Hood's division) to arrive, and then he was forced to march on a long, circuitous route that could not be seen by Union Army Signal Corps observers on Little Round Top. It was 4 p.m. by the time his two divisions reached their jumping off points, and then he and his generals were astonished to find the III Corps planted directly in front of them on the Emmitsburg Road. Hood argued with Longstreet that this new situation demanded a change in tactics; he wanted to swing around, below and behind, Round Top and hit the Union Army in the rear. Longstreet, however, refused to consider such a modification to Lee's order.^[70]

Even so, and partly because of Sickles's unexpected location, Longstreet's assault did not proceed according to Lee's plan. Instead of wheeling left to join a simultaneous two-division push on either side of the Emmitsburg Road, Hood's division attacked in a more easterly direction than intended, and McLaws's and Anderson's divisions deployed brigade by brigade, in an en echelon style of attack, also heading more to the east than the intended northeast.^[71]

Longstreet's attack commenced with a 30-minute artillery barrage by 36 guns that was particularly punishing to the Union infantry in the Peach Orchard and the troops and batteries on Houck's Ridge. Maj. Gen. John Bell Hood's division deployed in Biesecker's Woods on Warfield Ridge (the southern extension of Seminary Ridge) in two lines of two brigades each: at the left front, Brig. Gen. Jerome B. Robertson's Texas Brigade (Hood's old unit); right front, Brig. Gen. Evander M. Law; left rear, Brig. Gen. George T. Anderson; right rear, Brig. Gen. Henry L. Benning.^[72]