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. 
F in left field.
Mintmark ML. 

Little Orme hoard (1907): IARCW 921/52 (RIC 101 var: no letter in right field)
Very rare. rated R4.

With permission of cngcoins.com, 2006