AE 24mm   His draped bust right.  R. ΠOMΠ ΓΑΔΑΡΕΗΝ ΗΝ ΓΤ  Galley with rowers.  Cf. S.GIC. 3781.
ΓΤ = year 303 of the Pompeian era = 239 AD.  No obverse legend visible, much pitting, otherwise Good Fine

The information with this coin from the Albert Reeves collection says that it was bought for £10 on 3 Nov 1983 from Ian Johnson