Their plans were disconcerted by the sudden fall of Lerida; the Miguelettes were repulsed from Venasque; the Somatenes defeated at Tremp; and general Habert, marching from Balaguer, cut off Campo Verde from Cervera, and forced him to retreat upon Cardona. But, if the citadel of Lerida had held out, and O’Donnel, less hasty, had combined his march, at a later period, with these Somatenes and with Campo Verde, the third corps could scarcely have escaped a disaster; whereas, now the plain of Urgel and all the fertile valleys opening upon Lerida fell to the French, and Suchet, after taking measures to secure them, turned his arms against Mequinenza, which, by its situation at the confluence of the Segre and the Ebro, just where the latter begins to be navigable, was the key to further operations. The French general could not advance in force against Tortoza, nor avail himself of the water-carriage, until Mequinenza should fall. Suchet’s activity was extreme; one detachment, sent the day after the assault of Lerida, by the left bank of the Segre, was already before the place, and general Musnier’s division, descending the right bank of that river, drove in some of the outposts and commenced the investment on the 20th of May. Mequinenza, built on an elbow of land formed by the meeting of the Segre and Ebro, was fortified by an old Moorish wall, and strengthened by modern batteries, especially on the Fraga road, the only route by which artillery could approach. A shoot from the Sierra de Alcubierre filled the space between the two rivers, and narrowing as they closed, ended in a craggy rock, seven hundred feet high and overhanging the town, which was built between its base and the water. This rock was crowned by a castle, with a rampart, which being inaccessible on two sides from the steepness, and covered, on a third, by the town, could only be assailed, on the fourth, along a high neck of land, three hundred yards wide, that joined the rock to the parent hills; and the rampart on that side, was bastioned, lined with masonry, and protected by a ditch, counterscarp, and covered way with palisades. No guns could be brought against this fort, until the country people, employed by Suchet, had opened a way from Torriente, over the hills, and this occupied the engineers until the 1st of June. Meanwhile the brigade, which had defeated Lazan, at Alcanitz, arrived on the right bank of the Ebro, and completed the investment. The 30th of May, general Rogniat, coming from France, with a reinforcement of engineer-officers, and several companies of sappers and miners, also reached the camp, and, taking the direction of the works, contracted the circle of investment, and commenced active operations. SIEGE OF MEQUINENZA.