If you go through Bahrfeldt, Hersh or Crawford's tables of overstrikes you'll find something really shocking: there is only a single uncia-over-sextans overstrike listed from the D'Ailly collection and now in Paris. Crawford later published a second example in CMRR, but even so, you basically never see them. This is quite strange for a handful of reasons, first and foremost that the Crawford 38 semilibral semuncia is an extremely common type, and in theory should have been widely available for overstriking. Second, the Crawford 41/10 Uncia usually weighs 5-8 grams, about the same as the 38/7 semuncia, making it seem like an even better candidate for overstriking. Finally, many 41/9 sextantes are known overstruck on 38/6 unciae, so many that it almost seems like you see as many or more overstruck as on fresh flans. So why so few unciae overstruck on semunciae? If you hoped that I would have an explanation, unfortunately you'll be disappointed. I've got nothing. The Romans struck great numbers of 41/10 unciae so these should be very common. To me this overstrike falls into the category of coins you'd expect to be common, but in practice and even in specialized overstrike collections, you almost never see it. I have no idea why, but I was very happy when I finally managed to decode the undertype of this uncia that a friend pointed out to me. It took me a bit to get it, but if you look in front of the obverse chin you can see Mercury's petasos. On the reverse you can see a trace of the undertype prow's rostrum tridens poking out at the top left of the overstruck prow. The devices, style, module size and weight leave only a single possibility for the undertype: the 38/7 semuncia. I'll attach a photo at the end that will help you see it better if you can't spot of from the photo of the coin alone. 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 Purchased from London Ancient Coins, February 2020 As promised, this illustration may help you see the undertype if you're having trouble. Feel free to share any interesting overstrikes you may have.
Nice coin and interesting overstrike. I can see the undertype on the obverse thanks to your description and seeing the coins together. Thanks for the post!
And here is a much more common Crawford 41 Sextans overstruck on a Crawford 38 Uncia. The crest of Roma's helmet from the undertype Uncia is clearly visible beneath the Prow. Rome, The Republic. Anonymous Post-Semilibral, 215-212 BCE. AE Sextans (11.76g; 25mm) overstruck on AE Uncia. Rome Mint. Obverse: o/t: Head of Mercury wearing petasos, facing right; u/t: Prow facing right (not visible); Reverse: o/t: Prow facing right; ROMA above; two pellets below. u/t: Head of Roma in crested helmet, facing left (remnants of crest visible below prow). Over-type references: Crawford 41/9; Sydenham 107; BMCRR 72. Under-type references: Crawford 38/6; Sydenham 86; BMCRR 88. Overstrike references: Crawford Table XVIII, #18 (12 examples cited).
I would guess (I've not researched this) that the "small change" use of the semunciae perhaps meant that they rarely wound-up back in the state's coffers. The state probably used what they captured or had on hand (after a weight standard reduction) for overstriking. If my guess is correct, quartunciae should be similarly rare as an undertype. Still, at some point in the weight reductions, the overweight semuncia would have demanded special treatment - if not by the state, then by the consumer.
This is a very plausible theory and one I hadn't considered. You are correct that quartunciae are similarly rare as undertype. I'm not actually sure if I've ever seen one.
