Agrippa - issued by Gaius [Caligula] (37-41 A.D.) - Copper As - 29mm, 12.00gr
Obverse - M AGRIPPA L F COS III
Agrippa, his head left, wearing rostral crown.
Reverse - S C
Neptune standing left, wearing cloak, holding trident and small dolphin.

The image below was photographed by Nemesis Ancients & Antiquities. The image above is my own scan.

Minted in Rome between 37 and 41 A.D.
Reference:
Sutherland, C.H.V., "Roman Imperial Coinage", Volume 1, revised edition (RIC), p112, nr.58 (under Caligula)
Sear, D.R., "Roman Coins and their Values" (RCV Millennium Edition), Volume 1, p358, nr.1812
Sear, D.R., "Roman Coins and their Values" (RCV 4th Revised Edition), p101, nr.556  (under Agrippa)
Cohen, H, "Descriptions Historique des Monnaies frappees sous l'Empire Romain" (C), Volume 1, p75, nr 3 (under Agrippa)
Mattingly, H., "Coins of the Roman Empire in the British Museum", Volume 1 (BMC), p142-3, nr. 161-166.
Van Meter, D., "Handbook of Roman Imperial Coins", p74, nr. 4 (under Agrippa).
Suarez, R., "Encyclopedia of Roman Imperial Coins" (ERIC),  p12, nr.2 (B1, O1, R3, T1)
Quality: Very Fine