Watch List notes:

Bithynia, Kalchedon, (c.340-320 B.C.), silver siglos (Persian standard), (5.15 g), obv. bull standing to left, on corn-ear, above KALC rev. quadripartite incuse square of mill-sail pattern, (S.3738, SNG BMC Black Sea 112ff. [siglos], SNG von Aulock 482, HGC 7, 517). Good very fine, well centred, minor test cut on obverse, rare.

Ex Giesssener Munzhandlung, Dieter Gorny, c.1995.

A similar piece for the twin city (Byzantium) on the other side of the Bosphorus in this sale.