From the same Book I just referenced above in the previous post, the surname MARR appears at greater length than does that of Erskine. The Marr name spelled in many different ways, dates back to the 1200's in Scotland as well and one of them was even Chaplain to Joan who was Queen of Scotland. This book makes note of some Marr's as late as the 1730's in Edinburgh. Most of them are listed in the Aberdeen area however. Hope this is helpful.