Grant now turned his attention to possibilities on the eastern side of the Mississippi. By blowing up a levée he tried to open again an old and abandoned waterway from the Mississippi into the Yazoo river, by way of the Tallahatchie and Yalobusha rivers. Those two streams unite at Greenwood to form the Yazoo river. They are narrow, tortuous, uncertain of channel, and densely wooded along their banks. The Confederates with their ceaseless and alert activity swarmed on the banks of these rivers, and obstructed them not only by the fire of sharpshooters, and now and then of a field battery, trained against the advancing flotilla, but still more effectively by felling trees into the stream and thus rendering it impassable. Presently Grant found also that the Confederates were engaged in a system of defense still more dangerous to him than this. While obstructing his pathway down these streams in the way described they were also felling trees into the channels in the rear of his flotilla, and constructing strong earthworks along the banks above him. It was obvious that he must withdraw at once from his perilous position or encounter something worse than a mere risk of capture. The work of extricating himself was difficult, but with strong reinforcements continually coming to him Grant succeeded in accomplishing it. Still he did not abandon his hope of getting into the rear of Vicksburg by some movement from the north. The Yazoo river was connected by many bayous and other watercourses on the west of Haines Bluff with its tributary, the Big Sunflower. Grant decided to go up the Yazoo to Steele's Bayou and to go on up that watercourse, through some difficult passes into the Big Sunflower; thence he planned to descend the last-named stream, and strike the Yazoo again above the fortifications at Haines Bluff. If he could accomplish this he would have an open and comparatively easy road into the rear of Vicksburg. This effort was met and baffled, as the former one had been, by Confederate obstructions in the streams, and by ceaseless annoyance from the woodlands on the banks. So active were the Confederates that at one time Commodore Porter seriously contemplated the abandonment of all his gunboats and transports. His energy, however, and his wonderful skill in navigation saved him at last from this humiliating necessity. By backing through streams in which there was not room enough to turn around, he managed at last to retreat lobster fashion, through thirty miles of tangled and crooked waterways, under a constant and galling fire from the banks, and in the end to get back into openly navigable waters.