Watch List notes:

BOEOTIA. Koroneia. Circa 400-350 BC. Obol (Silver, 10 mm, 0.92 g). Boeotian shield. Rev. Gorgon's head facing, of late Classical style. BCD Boiotia 172. BMC 11. Weber 3202. Rare. Well-centered and with a dark patina. Some deposits on the reverse, otherwise, about extremely fine.
From the "Collection sans Pareille" of Ancient Greek Fractions and from the collection of L. Mildenberg.