considering it was 8 inchs about the same depth as a 1867 IH i dug there the other day id say your rightcedarratt said:From the looks of it and the fact that it is marked COIN and not STERLING I would say that it was a Victorean era ring. congrads on the find.
W!! WTG, Baron...love that ring and the news clip about you. Congrats!! 
RR

