Countermark

https://rpc.ashmus.ox.ac.uk/countermark/207 
GIC 86
male head r. (Caracalla?)
oval 
5 × 4 mm 
Possibly a cmk of Thyatira (GIC 93). Both cities stuck coins of this type 

Coins with this countermark

Number Image TypeNumber CoinNumber VolumeNumber
RPC V.2, — (number not assigned), type ID 37006 Show 2433 7 5.2