This big plaque is not original to the magazine...it was on the gatehouse, if I remember correctly. Somehow, some guy found it, kept it for years, and then donated it. The crossed cannons is the symbol of the US Ordnance Department, and April 1814 was when building of the arsenal began. At the bottom of the guns is A.R.W., the initials of Abram R. Wooley, the first commandant of the arsenal. And I believe the number of stars around it was the number of states in the union at the time.
This monument is at Allegheny Cemetery, about a half mile or so from the explosion. It lists the names of all 78 victims of the explosion, the overwhelming majority being female. 54 of the bodies could not be positively indentified, so they are buried in a mass grave under here. Others are buried individually, while a good number of Irish Catholic victims are buried separately in the St. Mary's portion of the cemetery, just past the fence behind the monument. Songwriter Stephen Foster - who was well-known during the Civil War era - is also buried in the cemetery. His father was one of the founders of Lawrenceville.