AE As 25mm (8.23gm)

Obv: Head Of Janus Rev: Ships prow right P CALP (?)

Cf. Syd. CRR Appendix C, pg 215.

I'm posting this even though it's inadequately researched in hopes that someone more knowledgeable than I can help. It's way too small and light to be any normal Janiform Republican As, yet it doesn't conform to any of the descriptions of "Fleet Coinage" I've ever seen either - Help!

Mark Lehman Collection