I found your picture disturbing, because my understanding is that the ancient Greeks used a big stone on a rope as an anchor. Also, Thrace is big and it was seldom united, but rather a collection of colonies from different Greek city states. Sure enough, the coins of united Thrace turned out to be different. My first guess was Lysimachios, because of the lambda at nine o'clock on the first picture. That was a dud as well.
A systematic search provided the answer to all my questions. The first picture (the reverse) is upside down. It seems to me that it's not an anchor, but a helmet. A helmet would be a far better match for Medusa than an anchor. The lambda is an alpha and the city is
Apollonia Pontika, now
Sozopol in Bulgaria.
That raises a new question. The drachmes of Apollonia Pontika are extensively counterfeited - Bulgaria is notorious for its imitations of classical coins made for tourists and collectors. I went through a large number of pictures of Apollonia Pontika coins, fake and genuine, without finding the bad hair Medusa on your coin. I did notice that the fakes were usually in a very desirable condition, which makes sense from the point of view of the faker.
On balance, I would take your coin for genuine, with having an uncommon design as an extra attraction. Congratulations, Greg. Neat and very interesting coin.
Peter
