Countermark

https://rpc.ashmus.ox.ac.uk/countermark/1378 
GIC 39
bust of Geta or Caracalla r.
circular 
to be used if impossible to distinguish 39i ΓΕ Geta or Α < Caracalla. Some of these might be "female bust r., hair in a bun (Domna?)" = take advice! 

Coins with this countermark

Number Image TypeNumber CoinNumber VolumeNumber