Watch List notes:

Thrace, Byzantion in alliance with Kalchedon Æ 26mm. 3rd century BC. Veiled head of Demeter to right / Poseidon seated to right, holding aphlaston and trident; ΒΥΞΑN[T] to right, ΚΑΛΧΑΔ to left, ΔA in inner right field. Schönert-Geiss 1258; SNG BM Black Sea 82; HGC 3.2, 1428. 10.66g, 26mm, 12h.

Extremely Fine.

From the inventory of a UK dealer.