Perhaps that's some damage to the mark, but I think that it may be 'JMc'?
The initials, and the Oar pattern handle, all point to a Scottish origin. The Incorporation of Edinburgh Goldsmiths website does have an image of a similar mark, but have it as 'unidentified'. Unfortunately, 'JMc' must be just about the commonest set of initials for a Scotsman and further identification may be difficult.
Hopefully someone else may have some thoughts.