I have discovered another tenuous link back to Dumfriesshire. I hope you can follow my reasoning

The person busybea is looking for is a Mary Anderson, who married James Arkless in County Durham in 1835, The witnesses to the marriage were James Anderson and Mary Anderson.
see
http://www.rootschat.com/forum/index.php/topic,485618.msg3438741.html#msg3438741There is a marriage of a James Anderson and a Mary Sanderson in County Durham in 1834, and one of the witnesses was a Mary Anderson.
In 1851 Mary and James Arkless were living in the same small town as a James and Mary Anderson and the 1851 and 1861 censuses show James being born in Scotland.
However, the 1871 census shows him as having been born in Dumfriesshire.
I admit the whole thing is unsubstantiated but it's a possibility.
Jennifer