I have a Constantius II (I think) Phoenix on Globe with a mint mark that I see as CONSS* (star) I can't find it. I can find some with slightly different mint marks. Any help would be appreciated.
Have you checked RIC 93 page 454 volume VIII? At that point the mint of Constantinople was using eleven workshops numbered A (1) through IA (11 in Greek numerals). My coin is a shop B (2). Yours is shop S (6). All are RIC 93.
Victor is quicker. If the concept of workshops is new to anyone, my page might help. http://www.forumancientcoins.com/dougsmith/officina.html
The break between RIC VII and VIII is the death of Constantine and the elevation of his three sons to Augustus. This coin shows Constantius II as Augustus so it is in VIII. The hard ones here are the Urbs Roma and Constantinopolis commemoratives which were started before Constantine died and continued after. For them, you need to look in both volumes.
Here is another one very similar in the search but the Fallen Horseman variation. My call is: Constantius Gallus, AE3. Constantinople. AD 347-355. DN FL CL CONSTANTIVS NOB CAES, bare-headed, draped, cuirassed bust right. FEL TEMP RE-PARATIO, soldier spearing fallen horseman who is bare-headed and bearded, reaching backwards. Dot in centre. Mintmark CONSIA. RIC VIII Constantinople 122.