What is it??

[ordfill992]

While searching around a church that is being demolished, I found this large cent sized coin around one of the corner stones.? Judging by the harp on the reverse, it's most likely Irish, but what year The church dates from the late 1800's.? The coin is well worn, but on the obverse I can make out the name "George III", and on the reverse above the harp, I can make out the letters "ERN", but that's all as far as any writing.? Thanks for any help.

[comfyinvermont]

Buckram is right. The date is at the bottom on the reverse, but the 17 will be on the left and the onther two numbers on the right and will be divided by the bottom of the harp. Hope that helps...Lance