Galerius (309-313 A.D.) -  AE2 Nummus (Follis) - 25.61mm, 6.52g
Obverse - IMP C GAL VAL MAXIMIANVS PF AVG
Galerius, his laureate head right
Reverse - GENIO IMP-E-RATORIS
Genius standing left, modius on head, naked but for chlamys
over left shoulder, right holding patera (from which liquor
flows), and left cornucopiae.
dot HTDelta dot in Exergue.

The image below was photographed by Caribou Coins. The image above is my own scan.
Minted at the 4th officina (delta) in Heraclea (Marmara Ereglisi, Turkey) between December 308 and the end of 309 A.D.

Exact References:
Sutherland, C.H.V., "Roman Imperial Coinage", Volume 6 (RIC), Heraclea, p535, nr 37a.
Voetter, Otto, "Die Münzen der römischen Kaiser, Kaiserinnen und Caesaren von Diocletianus bis Romulus, Katalog der
hinterlassenen Sammlung und Aufzeichnung des Herrn Paul Gerin"
(Voetter-Gerin), Heraclea, Galerius Maximianus, p114, nr 10.
Sear, D.R., "Roman Coins and their Values" (RCV Millennium Edition), Vol 4, p297, nr. 14513.
Suarez, R., "Encyclopedia of Roman Imperial Coins II" (ERIC II),  p806, nr.545 (B18, O17, R39, T45, M05, Exe: dot HTDelta dot)
Suarez, R., "Encyclopedia of Roman Imperial Coins II" (ERIC II-eBook), p670, nr.545 (B18, O17, R39, T45, M05, Exe: dot HTDelta dot)
Suarez, R., "Encyclopedia of Roman Imperial Coins III" (ERIC III-Galerius), p12, nr.600 (B19, O30, R44, T50, M05, Exe: dot HTDelta dot)


Other References (no distinction by mint and/or mintmarks):
Cohen, H, "Descriptions Historique des Monnaies frappees sous l'Empire Romain" (C), Volume 7, p107, nr. 8.
Van Meter, D., "Handbook of Roman Imperial Coins" (VM), p281, nr 28a.
Failmezger, V., "Roman Bronze Coins From Paganism To Christianity 294-364 A.D." (Fm), nr 197aG
Kampmann, U., "Die Münzen der römischen Kaiserzeit", 2nd edition (Kampmann), p121, nr. 122.64.

Quality: Very Fine
Rarity: C (Common)