Watch List notes:

Caracalla (198-217). Debased AR Denarius, Rome mint, 199-200. Obv. ANTONINVS AVGVSTVS. Laureate, draped and cuirassed bust right. Rev. AETERNIT IMPERI. Busts of Septimius Severus, laureate, draped and cuirassed right and Caracalla, laureate, draped and cuirassed left, facing one another. RIC IV 32; C. (Caracalla and Septimius Severus) 2 (Fr. 60). AR (debased). 2.94 g. 18.50 mm. RRR. Very rare and choice. Dark patina, green spots. Good VF. About the attribution of reverse younger portrait to Caracalla (not to Geta) see the interesting notes of Cohen (IV, p. 242,1) and RIC 32.