At Crampton's gap of the South mountain, six miles to the southward from Turner's gap and Hill's field of action, another battle raged on that same Sunday afternoon. McLaws had left 1,200 men to hold that pass, in guarding his rear, while he occupied Maryland heights. Against these Franklin threw 8,000 from his advance. The resistance lasted until dark, when the Confederates gave way and Franklin took possession of the gap, and thus interposed the head of a strong Federal column between Lee at Boonsboro and McLaws in Pleasant valley and on Maryland heights.
Lee might have said to himself, in the words of Longstreet at Groveton, as he reflected on the positions of his army at the close of the 14th, that the prospect "was not inviting." The two divisions in his immediate presence were not compacted; Longstreet was advising that something else than fighting be done. The other three of his divisions were a dozen miles away, separated from each other by great rivers, and could only reach him by circuitous marches and after the fall of Harper's Ferry, an event which had not yet taken place. His stout heart was doubtless throbbing with intense emotion, which none but a heroic and God-trusting spirit could control, when, at 8 of the evening, nearly two hours after sunset, he wrote to McLaws: "The day has gone against us, and the army will go by Sharpsburg and cross the river. It is necessary for you to abandon your position to-night; . . your troops you must have in hand to unite with this command, which will retire by Sharpsburg."
The outlook to McLaws was a brighter one. The investment of Harper's Ferry was completed, and neither officer nor soldier doubted but that, with Jackson in command, the early morning of the 15th would find him in possession of that town, of the 11,000 Federals there beleaguered and of the large munitions of war there gathered. So McLaws promptly added to his line in Pleasant valley, to which his men had fallen back from Crampton's gap, and prepared to hold his rear against Franklin's advance until Harper's Ferry was captured and the way opened for him to cross the Potomac on the Federal pontoon, and in that way, through Virginia, reach Lee at Sharpsburg, as he was ordered to do. Lee's vigorous defense of the South mountain passes near Boonsboro had won a day from McClellan and given Jackson time to complete the investment of Harper's Ferry.
