Statistics for occurrence #1 of “Merrimac” in chapter 78, page 253 of Rebellion Record: a Diary of American Events: Documents and Narratives, Volume 5.:
...istaken for the enemy, were fired into by the Twenty-first Mississippi regiment, as was Jenkins's South-Carolina regiment at Manassas, by reenforcements in the rear.
During the pursuit the railroad Merrimac was far in advance of our men, and was vigorously shelling the enemy at every turn.
...