Countermark

https://rpc.ashmus.ox.ac.uk/countermark/631 
GIC 504 ii
'various curvilinear motifs with pellets'
irregular 
uncertain 
Might have been applied at Dura 

Coins with this countermark

Number Image TypeNumber CoinNumber VolumeNumber
Show 58
RPC I, 4264 Show 4264 10 1