Constans, AE follis of Lyons, AD 346-348.

CONSTANS AVG, rosette-diademed, draped, cuirassed bust right.
GLORIA EXERCITVS, two soldiers standing facing each other, 
each holding spear and resting hand on shield with 
one standard between them with a crossbar on the mast and 
a Chi-Rho on banner.

Mintmark PLG or SLG. 
RIC VIII Lyons 9

Contributed by Saul Roll of Romanorum.com