 Complete the following phrase:  To supplement the treadway bridge, engineers constructed a Bailey bridge that was opened to traffic on 23 August. On the east bank, the 79th Infantry Division not only extended and improved the bridgehead, repelled counterattacks, and interdicted highways, ferry routes, and barge traffic lanes, but also dramatically pointed out to the Germans their critical situation by capturing the Army Group B command post at la Roche-Guyon and sending the German headquarters troops fleeing eastward to Soissons. Once the Allies were on the east side of the Seine, the Free French 2nd Armored Division and US 4th Infantry Division were able to 