This type was once associated with Vienna or Lyons, but according to RPC hoard evidence point towards Narbonese in Southern France.
Denomination : AE 30, probably meant to circulate as a dupondius
Mint : Narbo
Date : issue of ca. 40 BC.
Reference : PRC volume 1, #518.
Size : 29.5 x 31.0 mm. Weight : 16.12 grams.
Grade : Fine, slight porosity. Very dark brown patination.
Obverse : Head of Octavian right, with CAESAR behind (only the CAES is struck up).
Reverse : Prow of a galley with it's superstructure and mast.