Countermark

https://rpc.ashmus.ox.ac.uk/countermark/491 
GIC 371
anchor
circular 
7 mm 
Interpreted by Youroukova as a cmk of Apollonia on the Black Sea coast 

Coins with this countermark

Number Image TypeNumber CoinNumber VolumeNumber
RPC I, 1710 Show 1710 6 1
RPC I, 1710 Show 1710 16 1