Watch List notes:

CELTIC, Durotriges. Uninscribed. Circa 65 BC-AD 45. Pale AV Stater (20mm, 5.73 g, 7h). Durotrigan E, Abstract (Cranborne Chase) type. Devolved head of Apollo right / Disjointed horse left; pellets above, pellet below, pellet in lozenge above tail; [zigzag and pellet pattern between two parallel exergue lines]. Van Arsdell 1235-1; ABC 2157 note; cf. SCBC 365 ('Silver Stater'). Near EF, toned.

The higher weight and gold content of this piece clearly place it at the earliest stage of this large issue that quickly devolves into silver and eventually billon. While Van Arsdell's general listing for his 1235-1 type encompasses all metal types, SCBC only lists the silver and billon.