[Sir Taliesin]

The men of Carn Dum, were descended from Numenor. At some point the Northern Kingdom was divided in to three smaller Kingdoms. Carn Dum was one of them.

Also I must point out that the men of Westerness were descended from the Men of the First Age that aided the Elves in their fight with Morgoth. The First Ruler of Numenor was in fact Elrond's brother. Not quite sure where you got that they were of a Mediterrean origin, because I'd tend to think they were more of a Northern European origin. Especially, since Tolkien was attempting to write a fictional ancient history for Britian.