Countermark

https://rpc.ashmus.ox.ac.uk/countermark/440 
GIC 318
animal suckling child in oval punch
oval 
8 x 5 mm 
Pergamum (Mysia)
its use on a much smaller diameter coin shows it was unlikely to be a denominational cmk 
List of countermarks View on a map

Coins with this countermark

Number Image TypeNumber CoinNumber VolumeNumber
RPC VI, 4210 (temporary) Show 3571 2 6
Show 156