American Military History, Volume 1 by Richard W. Stewart

Containing some of the best regular units in the Mexican Army, General Arista's forces barring the road to Fort Texas stretched out on a front a mile long and were about 4,000 strong. Taylor, who had placed part of his force in the rear to guard the supply wagons, was outnumbered at least two to one; and in terrain that favored cavalry, Arista's cavalry overwhelmingly outnumbered Taylor's dragoons. On the plus side for the Americans, their artillery was superior. Also, among Taylor's junior officers were a number of capable West Point graduates, notably 2d Lt. George C. Meade and 2d Lt. Ulysses S. Grant, who were to become famous in the Civil War.

On the advice of the young West Pointers on his staff, Taylor emplaced his two 18-lb. iron siege guns in the center of his line and blasted the advancing Mexicans with canister. His field artillery-bronze 6-lb. guns firing solid shot and 12-lb. howitzers firing shell, in quick-moving attacks threw back Arista's flanks. The Mexicans were using old-fashioned bronze 4-pounders and 8-pounders that fired solid shot and had such short ranges that their fire did little damage. During the battle Lieutenant Grant saw their cannon balls striking the ground before they reached the American troops and ricocheting so slowly that the men could dodge them.