Hi Jim
I know you've closed this thread as being "solved" but thought I'd give you a further shove in the right direction
Given the combination of parent names but most especially the occupation of blacksmith I've narrowed in on this family in 1851:
Name: James Nelson
Age: 52
Estimated Birth Year: abt 1799
Relationship: Head
Gender: Male
Where born: Ireland
Parish Number: 899
Civil parish: Stranraer
County: Wigtownshire
Address: Hanover St
Occupation: Black Smith
ED: 4
Page: 48 (click to see others on page)
Household schedule number: 202
Line: 1
Roll: CSSCT1851_217
Household Members:
Name Age
James Nelson 52
Elizebeth Nelson 20 b. Ireland
Janet Nelson 17 b. Colomonell, Ayrshire
Margret Nelson 14 b. Newbell, Wigton
Arther Nelson 10 b. Portpatrick, Wigton
Benjemin Nelson 8 b. Portpatrick, Wigton
William Nelson 6 b. Portpatrick, Wigton
Alexr Nelson 4 b. Portpatrick, Wigton
Note daughter Margert born about 1837 and no wife present in the household. I looked for brother Benjamin and found what looked like him in 1861 working as a coachman at Lambhill House in Maryhill Glasgow. So I looked further for a possible marriage of him and found one in 1874 Blythswood to Catherine Best on which he states his parents were James Nelson, blacksmith, and Jane Nelson mn Robertson both dec'd. That looked pretty good to me! So next I've looked for marriages for the older sisters to Margert. I'm out of time at the present to go further but did find sister Jane Nelson marrying John Innis in Stranraer in 1855. Sadly Jane had been born in Colmonell Ayrshire so no clues to origins in Ireland other than her hubbie John Innis, occ: shoemaker, claims to have been born in Kirkcubbin...which according to my google search is in County Down. At the time of her marriage in 1855 she lists mother Jane Robinson as being dec'd but father James Nelson is not. I would start looking for a death of James Nelson between 1855 and 1871 for starters. It looks like the mom has possibly died in Portpatrick between 1847 and 1851. I did not find them on the 1841 census yet.
Best wishes
Jean
PS...have had a look at the original 1851 census page and note that Margaret's palce of birth "newbell" as transcribed on Ancestry.com is most certainly written
Newluce on the original.