Constans, AE3, Siscia. 346-348 AD.

CONSTAN-S PF 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 banner.

Mintmark: ASIS dot in crescent

RIC VIII Siscia 99, rated C2.

From Dane's collection, August 2010.

Known mintmarks for this RIC number:
ASIS dot in crescent
BSIS dot in crescent
gamma SIS dot in crescent
delta SIS dot in crescent
epsilon SIS dot in crescent