Hi Steve,
The date is clearly marked as "June 30, 1880" and the title of both plates is "The Holocaust of the Sound." It also clearly states "The Daily Graphic, New York" on one of the plates. The New York Daily Graphic had a very unique cover which is consistent with this metal plate (see below baseball example)...the metal plate is simply missing "The" in "The Daily Graphic."
The plate says "Destruction of Seawanhaka by Fire Last Monday." I was able to find the below link which provides more details on the sad events of that day.
http://www3.gendisasters.com/new-yor...ster,-jun-1880