Watch List notes:

IONIA AND CARIA. Uncertain mint. Circa 480-450 BC. Obol or Hemihekte (Silver, 9.5 mm, 1.14 g). Gorgoneion with snaky hair and protruding tongue. Rev. Irregular incuse square divided into two rectangular incuses by a central band. Lanz 144, 2008, 232 and SNG Kayhan 741 (same dies). Very rare. With a powerfully ferocious gorgoneion. Somewhat rough surfaces, otherwise, about extremely fine.
From the "Collection sans Pareille" of Ancient Greek Fractions, ex Hauck & Aufhäuser 14, 6 October 1998, 143 (but as Ephesos).