CIMRM Supplement - Mithraeum II - Tauroctony. Köln, Germany.
A tauroctony. The dog, snake and scorpion in their usual positions. Sol in the top left with a rayed crown, one ray of which is extended out towards Mithras. Beneath Sol a raven. A cock facing the bull on the right-hand side.
RP: Found online. Presumably from Mithraeum 2, discovered in 1969. In the Romisches-Germanisches Museum, Köln.
See also Wikimedia Commons item which gives the date as 2-3rd c. AD.