Cr. 41/10 McCabe A2 uncia overstruck on semilibral semuncia
Roman republic Æ Uncia(6.06g, 22mm, 10h), anonymous "post-semilibral" series. 215-212 BC. Head of Roma right, wearing attic helmet; to left, • / Prow right; above, ROMA; below, •. McCabe Group A2; Crawford 41/10
Overstruck on semilibral semuncia, Crawford 38/7, McCabe Group AA; For 41/10 overstruck on 38/7, cf. Crawford, table XVIII 20, Hersh 40, Bahrfeldt 5
This uncia is only the third Roman overstrike on a semuncia known to me. For some reason, even though the Crawford 38/7 semilibral semuncia is one of the most common struck Roman Republic bronzes, they were apparently almost never overstruck. Bahrfeldt, Hersh and Crawford all cite only a single known example from the D'Ailly collection now in the BNF Paris. Crawford, later in CMRR, also cites a 69/6 corn-ear KA sextans overstruck on a semuncia.
It's hard to see at first, but you can see the petasos and its wings right in front of the chin on the obverse. This photo may help you see the overstrike.