 Complete the following phrase:  During the MexicanAmerican War, Gardner served under Major General Winfield Scott. He was promoted to Major in 1845 and commanded the 4th Artillery Regiment from 1846 to 1848. He was stationed at Fort Polk in Texas between July 29, 1846, and January 31, 1847. He fought at the Battle of Cerro Gordo on April 18, 1847, and was brevetted as a lieutet colonel for Gallant and Meritorious Conduct. He served in the 