undetermined Greek coin

?, , ? BC.,
Æ 20 (18-20 mm / 8,35 g), bronze, axes irregular alignment ↑↖ (ca. 310°),
Obv.: laureate head of Zeus or Poseidon right.
Rev.: ... , figure standing left, leaning with left on sceptre or staff, holding (patera?) in outstretched right, altar(?) to r.
.