Constantine II, AE4, Cyzicus. 330-335 AD.

CONSTANTINVS IVN NOB C, pearl diademed, draped, cuirassed bust right 
(actually a laurel diadem, but the Cyzicus engravers often made the 
leaves resemble pearls).
GLOR-IA EXERC-ITVS, two soldiers holding spears and shields,
standing to left and right of two standards with O on banner.

Mintmark: dot SMK epsilon.
RIC VII Cyzicus 98, rated R3

Known mintmarks for this issue:
dot SMKA
dot SMKB
dot SMK gamma
dot SMK delta
dot SMK epsilon
dot SMKS

With permission of Roma Numismatics, April, 2011