Battle of South Mountain
“With the fields of fire spread out over a space of nearly six miles over dense forest cover, the first day at South Mountain featured some of the most intense small unit fighting of the war. It was a fight of rifleman against rifleman, led by captains, colonels, and brigadiers.”
-- Joseph Harsh, Confederate Tide Rising: Robert E. Lee and Confederate Strategy in the Maryland Campaign of 1862
"Though the two armies made contact late on the afternoon of the 14th, the real fighting did not begin in earnest until the 15th. McClellan, who had received intelligence indicating Confederate presence at locations from Williamsport all the way to the Pennsylvania border, correctly believed that Lee had divided his army, and devised a plan he believed would exploit Lee's weakness without creating a salient that Lee could turn against him. Beginning in the southern portion of his line, William Franklin's VI Corps would attack Crampton's Gap in the morning of the 15th, at which point Reno's IX Corps and Hooker's I Corps would attack en echelon at Fox's and Turner's Gap's, respectively. The center wing under Edwin Sumner stood in reserve to exploit any breakthroughs in the northern portion of the line, while Darius Couch's division stood in reserve for Franklin.
While the plan was tactically sound, a number of operational miscues led to its failure overall. Chief among these failures was the tardiness of Franklin's attack at Crampton's Gap. His attack, which was supposed to have begun in the morning, did not commence till midday. By that time, almost all of Lafayette McLaws' troops, which the day before had been spread throughout the Pleasant Valley and on the Maryland Heights besieging Harper's Ferry, had arrived to reinforce the line at Crampton's Gap. The two forces were nearly evenly matched, and the Confederates, lined up behind successive stone walls amidst a wooded area, held the high ground.
Although the Union forces arrayed against Fox's and Turner's Gaps had a numerical advantage, the Confederates under Longstreet and Hill had held the ground for more than a day and a half by the time Reno and Hooker began their assaults on the afternoon of the 15th. The Confederates were well dug in, and had fortified their positions with logs to block the roadways, abatis, and entrenchments..."
--Wikipedia.org The Battle of South Mountain
"Though South Mountain is often held up as one of Lee's greatest victories, it is usually forgotten that Lee, who had broken his hands on the 31st of August, was confined to an ambulance and was mostly absent from the front during the great battle. (It was not until the 16th that Lee could again ride a horse, and even then, he needed an orderly to hold the reins for him.) While it is true that the most spectacular actions at South Mountain took place on the 16th, without Longstreet's stubborn defenses of Fox's and Turner's Gaps on the 15th, neither Jackson's flanking movement nor Hill's envelopment the next day would scarcely have been possible."
-- Harold Knudsen, The Confederacy's Most Modern General: James Longstreet and the War of Secession
"Unfortunately, no contemporary records of the famous council of war at Boonsboro on the night of the 15th are extant, so the historian must pick through the conflicting accounts of the surviving generals, all made many years after the fact. While Jackson and Longstreet disagree in their recollections as to whose idea it was to turn the Union line in the north, all three--Jackson, Longstreet, and D.H. Hill--agree the it was Hill's idea to use Walker's division, who had missed out on the fight on the 15th, to flank Franklin's Corps through the Brownsville Gap. "
--Hal Bridges, Lee's Maverick General: Daniel Harvey Hill