That's a "Colonial" age button. The "Tallio" and the little fox are symbollic of fox hunting of course. I'm guessing anywhere from mid/late 1700's to early/mid 1800's, possibly a bit later but not too much. Great find. I have a cufflink just like it, only oval instead of round, found on an early 1800's site where American settlers camped while being directed to open land.