Constantine I, Lyons, AE 3/4. 337-348 AD. Possibly struck by Constantine II.

CONSTANTI-NVS MAX AVG, rosette-diademed, draped, cuirassed bust right.
GLOR-IA EXERC-ITVS, two soldiers holding spears and shields with one standard between them. Chi-rho on standard with slanted crossbar.

Mintmark SLG.

RIC VIII Lyons 7; Failmezger plate coin 373 CIa.
Rated rare.

RIC VIII, page 170 explains the slanted crossbar as a consecration 
for Constantine I, a sign of mourning.
The slanted crossbar types are scarce.

Contributed by Mark Dunning, March 2013.