To fill in some gaps for me and anyone else searching. This is the family in 1861 -
Caerlaverock, DFS
815 Ed 3 page 8-9
Maxwell Clark, 32, ploughman, b. Kirkgunzeon
Mary, 38, b. Caerlaverock,
James C, 12, b. Caerlaverock
Jannet , 10, b. Caerlaverock
Agnes M, 8, b. Caerlaverock
Maxwell JC, 6, b. Caerlaverock
Mary C, 1, b. Caerlaverock
Jane C, 2 months, b. Caerlaverock
Given that there is a daughter Agnes and not Ann, i would think that the mother Agnes Millar should not be discounted.
John Maxwell Crosbie Clark (aged 6 on here) was b. 4 Feb 1855. It would be worth downloading his birth cert from SP as the 1855 ones give a lot more info than the others.
I'll continue the search.
Gadget