<P> The sequence of retreating units remains unclear . Each of the two corps cast blame on the other . There are three main versions of events extant . The first, most prevalent, version is that the fiasco on Barlow's Knoll triggered a collapse that ran counterclockwise around the line . The second is that both Barlow's line and the Seminary defense collapsed at about the same time . The third is that Robinson's division in the center gave way and that spread both left and right . Gen. Howard told Gen. Meade that his corps was forced to retreat only because the I Corps collapsed first on his flank, which may have reduced his embarrassment but was unappreciated by Doubleday and his men . (Doubleday's career was effectively ruined by Howard's story .) </P> <P> Union troops retreated in different states of order . The brigades on Seminary Ridge were said to move deliberately and slowly, keeping in control, although Col. Wainwright's artillery was not informed of the order to retreat and found themselves alone . When Wainwright realized his situation, he ordered his gun crews to withdraw at a walk, not wishing to panic the infantry and start a rout . As pressure eventually increased, Wainwright ordered his 17 remaining guns to gallop down Chambersburg Street, three abreast . A.P. Hill failed to commit any of his reserves to the pursuit of the Seminary defenders, a great missed opportunity . </P> <P> Near the railroad cut, Daniel's Brigade renewed their assault, and almost 500 Union soldiers surrendered and were taken prisoner . Paul's Brigade, under attack by Ramseur, became seriously isolated and Gen. Robinson ordered it to withdraw . He ordered the 16th Maine to hold its position "at any cost" as a rear guard against the enemy pursuit . The regiment, commanded by Col. Charles Tilden, returned to the stone wall on the Mummasburg Road, and their fierce fire gave sufficient time for the rest of the brigade to escape, which they did, in considerably more disarray than those from the Seminary . The 16th Maine started the day with 298 men, but at the end of this holding action there were only 35 survivors . </P> <P> For the XI Corps, it was a sad reminder of their retreat at Chancellorsville in May . Under heavy pursuit by Hays and Avery, they clogged the streets of the town; no one in the corps had planned routes for this contingency . Hand - to - hand fighting broke out in various places . Parts of the corps conducted an organized fighting retreat, such as Coster's stand in the brickyard . The private citizens of Gettysburg panicked amidst the turmoil, and artillery shells bursting overhead and fleeing refugees added to the congestion . Some soldiers sought to avoid capture by hiding in basements and in fenced backyards . Gen. Alexander Schimmelfennig was one such person who climbed a fence and hid behind a woodpile in the kitchen garden of the Garlach family for the rest of the three - day battle . The only advantage that the XI Corps soldiers had was that they were familiar with the route to Cemetery Hill, having passed through that way in the morning; many in the I Corps, including senior officers, did not know where the cemetery was . </P>

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