Countermark

https://rpc.ashmus.ox.ac.uk/countermark/615 
GIC 490
?, 'circle'
circular 
5 mm 
On reverse 

Coins with this countermark

Number Image TypeNumber CoinNumber VolumeNumber
RPC VI, 30783 (temporary) Show 4368 1 6
RPC VI, 30783 (temporary) Show 4368 2 6