 Complete the following phrase:  During the American Civil War in late August, 1864, General Benjamin Butler, commander of the Union Army of the James, ordered the construction of a canal at Dutch Gap. One purpose of the canal was to allow ships to bypass the loop of the James river around Farrars Island, which was controlled by Confederate batteries. Of particular threat was Battery Dantzler at the northern end of the Howlett Line where Confederate forces had installed two seven-inch Brooke rifles, two ten-inch Columbiad guns, and two siege mortars that had a half mile field of fire on the James River that lay on the east side of Farrars Island. Another purpose was to continue military activity as part of the larger 