These are large silver thaler coins of King Maximilian III Josef of the old German State of Bavaria. There are several different patterns. This one uses a portrait of the king on the front and an ornate shield supported by two lions on the back. All old thalers are eagerly sought by collectors, and these are no exception:
THALERS WITHOUT 'A' MINT MARK:
worn: $40 US dollars approximate catalog value
average circulated: $120
well preserved: $250
These values apply to all dates, but there are three dates that sometimes carry and 'A' (for Amberg) mint mark. The mint mark appears under the king's portrait.
THALERS 1763A, 1767A, 1768A
worn: $60 US dollars approximate catalog value
average circulated: $220
well preserved: $600
The coin in our photo (upper left) is well worn and it has picked up some spiffy blue and gold toning over the years. It sold for $50 US dollars during a 2008 auction by Stack's. CoinQuest, as always, is indebted to Stack's for the use of their coin photo. Many thanks.