undetermined Greek silver plated coin

Caria(?), , 450-350 BC.,
Trihemiobol(?) (11-12 mm / 1,61 g), silver-plated, axes coin alignment ↑↓ (ca. 180°),
Obv.: forepart of a bull left.
Rev.: M (or Σ ?) , forepart of a bull left, in an incuse squre.
cf. SNG Keckman 1 916 = Auct. Peus 320, 1117 ; Troxell FS Mildenberg p. 256, 12B var. (2 pieces listed in Isegrim database, 2,14 and 2,01 g., pure silver, unplated).