This is the Hunting Chisholm tartan.

I'm desparately looking for the reference to this, but I've read in a book on Tartans that the name "Hunting" Chisholm does not refer to the tartan used when the Chisholms were hunting.

Hunting was actually the name of an Englishman who some time during the nineteenth century, after the wearing of tartan had ceased to be proscribed, found a pattern book of Tartans. All Tartans prefixed by Hunting are actually from this Pattern book.