Watch List notes:

THRACE. Byzantion. late 3rd-2nd centuries BC. (Bronze, 25 mm, 8.87 g, 12 h), alliance issue with Kalchedon in Bithynia. Veiled head of Demeter to right, wearing wreath of grain ears. Rev. ΒΥZANTI / KAΛΧΑΔ Poseidon seated right on rock, holding aphlaston in his right hand and trident in his left; to right, monogram of ΠΑΡ. HGC 3.2, 1428. SNG BM Black Sea 83. Green patina. Very fine.
From the Byzas Collection.