G. S. Hillard, Life and Campaigns of George B. McClellan, Major-General , U. S. Army

“ [26] Smith's own brigade, under the temporary command of Major Dimmick, following the movements of Riley and Cadwallader, discovered opposite to and outside of the works a long line of Mexican cavalry, drawn up as a support. Dimmick, having at the head of the brigade the company of sappers and miners under Lieutenant Smith, engineer, who had conducted the march, was ordered by Brigadier-General Smith to form line faced to the enemy, and, in a charge against a flank, routed the cavalry.”

In the reports of the officers immediately commanding, honorable mention is made of Lieutenant McClellan and his corps. General Twiggs says, “Lieutenant G. B. McClellan, after Lieutenant Callender was wounded, took charge of and managed the howitzer battery (Lieutenant Reno being detached with the rockets) with judgment and success, until it became so disabled as to require shelter. For Lieutenant McClellan's efficiency and gallantry in this affair, I present his name for the favorable consideration of the general-in-chief.” And again, “To Lieutenant G. W. Smith, of the engineers, who commanded the company of sappers and miners, I am under many obligations for his services on this and many other occasions. Whenever his legitimate duties with the pick and spade were performed, he always solicited permission to join in the advance of the storming-party with his muskets, in which position his gallantry, and that of his officers and men, was conspicuously displayed at Contreras as well as Cerro Gordo.”