Careful attention was paid to the choice of a route. That through Cadereita offered the better grazing; but the General wisely determined to march by way of Mier and Cerralvo, a distance believed to be 140 miles but in reality only about 125. This route was a little shorter and better provided with water. The roads were much more satisfactory. The problem of crossing the San Juan without boats or graded approaches did not present itself. The groves and ravines where an enemy could make trouble were few, and but one stream had to be forded. On August 19, therefore, Brevet Brigadier General Worth, commanding the Second Division of regulars, crossed the river with his first brigade over a bridge of steamboats, and moved off to establish a dépôt at Cerralvo, about sixty miles away. All the pack-mules, which were to return under escort and make a second trip, accompanied the troops. Brigadier General Persifor F. Smith and the second brigade, Brigadier General Twiggs with the First Division of regulars and about 180 wagons, and Major General W. O. Butler with a "Field Division" of volunteers followed. September 5 headquarters moved, and in a day or two the last of the men belonging to the expedition set out.[11.8] The advance to Cerralvo did not prove entirely agreeable. At first there was trouble because the mules could not be loaded until after daybreak, and it was hard for the troops to march during the hot hours; but after a little experience the troops moved off at about three o'clock in the morning, and the train proceeded later under escort. The road proved to be full of sharp stones most of the way; and everything--even the frogs and the grass--had thorns, reported the soldiers. Although, as Worth said, there was no dangerous lack of water, the men suffered not a little during a part of the time. Some almost raved from thirst, and brushing the yellow scum aside, would drink eagerly from any pool. The heat baked them, and in spite of wet cotton in their caps a considerable number were overcome. Mier, the only town of any importance on the route, proved to be the roughest and gloomiest sort of a place. Gloomy, too, was the long line of wooden crosses beside the road, for every one marked a grave, and not a few signified a murder. After a while, however, came the inspiring sight of distant mountains--the fantastic, pale-blue summits of the Sierra Madre, which rose higher and stood out more boldly day by day; and the occasional inhabitants appeared, as Worth reported, "cordial in the highest degree."[11.9]