I love the expression on this gorgon's face. I bought this obol in 2001 from Lanz's auction of Mr. BCD's Corinth collection. I'm very happy that my example of this coin comes from my favorite die of the type. It's a tiny coin; just 10mm across.
My version is a later example. I'm guessing it was made between 400 BC and the Macedonian occupation of 338 BC.
The earlier coinage featured a stern gorgon in an incuse square with the letters TRIH, for trihemiobol, in the corners. Although E. M. Cousinery attributed an example of this coin to Corinth in 1825 a paper by H. P. Borrell in the Numismatic Chronicle of 1840 argued for Tiridia in Thrace, a city with no known coinage, based on Borrell's misunderstanding of the inscription.
The same type was struck by Anaktorion, Leukas, and Medeon in Akarnania. The attribution to Medeon isn't secure; the M could be for Metropolis, Mesma, or it could be a Σ on it's side. It would be nice to assemble a set of these by mints but I probably won't live long enough. Coins of Medeon are rare! A note in the BCD auction (Akarnanien, October 2007) for a stater of Medeon says it is the only silver coin from that city to appear on the market during the last 40 years.
WGS Antiquarian Sale now in progress - http://eepurl.com/bk6-Xb
18 hours ago