Carausius, AE antoninianus, Camulodunum mint. 20mm, 4.64 g. 

IMP CARAVSIVS PF I AVG, radiate, draped and cuirassed bust right.
SALVS AVG, Salus standing left by altar, feeding serpent rising from the altar, and holding sceptre.

No mintmark. 
Elsen 145, 403. RIC V-2, 510-520 var (obv. legend)

With permission of Jean Elsen & ses Fils Auction 145, Lot 403, Sept. 2020