Countermark

https://rpc.ashmus.ox.ac.uk/countermark/305 
GIC 178
head l.
circular 
5 mm 
Coin referenced is from Epiphaneia (Cilicia) P: 540 

Coins with this countermark

Number Image TypeNumber CoinNumber VolumeNumber
RPC II, 1787 Show 1787 3 2
RPC II, 1787 Show 1787 2 2