Countermark

https://rpc.ashmus.ox.ac.uk/countermark/548 
GIC 426
plough?
rectangular 
9.5 x 7 mm 
on reverse, one on obverse 

Coins with this countermark

Number Image TypeNumber CoinNumber VolumeNumber
RPC I, 641 Show 641 35 1
RPC I, 644 Show 644 14 1
RPC I, 660 Show 660 22 1
RPC I, 660 Show 660 27 1
RPC I, 660 Show 660 34 1
RPC I, 660 Show 660 35 1
RPC I, 641 Show 641 4 1
RPC I, 642 Show 642 34 1
RPC I, 660 Show 660 6 1
RPC I, 642 Show 642 36 1
RPC I, 660 Show 660 38 1
RPC I, 660 Show 660 39 1
RPC I, 660 Show 660 4 1
RPC I, 660 Show 660 10 1
RPC I, 660 Show 660 15 1
RPC I, 642 Show 642 40 1
RPC I, 642 Show 642 40 1
RPC I, 642 Show 642 41 1