Countermark

https://rpc.ashmus.ox.ac.uk/countermark/1571 
GIC
+ or X in circular punch, points of X touching the circumference
circular 
3.5–4 mm 
on reverse 

Coins with this countermark

Number Image TypeNumber CoinNumber VolumeNumber
RPC II, 967 Show 967 10 2
RPC II, 968 Show 968 11 2