Marcus Aurelius, AE23 of Cassandrea, Macedonia, 161-180 AD.

Obv: IMP M AVR ANTON AVG, laureate head right.
Rev: COL IVL AVG CAS, Poseidon, naked, standing facing, head left, holding dolphin and trident.

Varbanov 3346 (this coin); Paris 607

from an orphaned folder, Jan. 2011