Carausius, AE antoninianus. London mint. 

IMP CARAVSIVS PF AVG, radiate, draped and cuirassed bust right.
PAX AVG, Pax standing left holding branch and vertical
sceptre. 
B-E across fields.
Mintmark MLXXI. 

RIC V-2, London 101.

with permission of cngcoins.com, 2004