 Complete the following phrase:  These boats soon became popularly known as Cumberland pontoons. Merrill had the first ones constructed in the armys engineer workshops in Nashville, Tennessee, under the supervision of Lieutet James R. Willet. Soon, a train of fifty new boats was transported to the field armies. William T. Sherman used the new bridges extensively during the first two months of the Atlanta Campaign, first laying them across the Etowah River. He later used them during the 