Poseidonia Lucania ca 470-445 BC. AR Nomos (Stater) 18 mm, 7.96 g. 

Obv.: POMEI to right of Poseidon, naked but for chlamys 
across shoulders, walking right, brandishing trident.
Rev.: POM (retrograde) above bull walking right. 

SNG ANS 645 (same dies) Sear 424v ($350 in VF); 

With permission of Roma Numismatics, Oct. 2015.
Estimate: £300