Septimius Severus, 193-211 AD, AE 29 of Anchialus, Thrace.

Obv: AV K L CEP CEVHPOC, laureate head right.
Rev: OVLPIANWN AGXIALEWN, city gate, flanked by two
battlemented towers, railing along top, surmounted by Poseidon standing
right, one leg drawn back, holding hippocamp and trident. 
Delta in square doorway.

Varbanov 201.

Courtesy of Ray, http://citygate.ancients.info, March 2011