The census returns that I have don't match for John Fleming. According to the marriage record of his daughter Mary to Daniel McCormick in 1856 in Glasgow, her parents are John Fleming (Carter/Deceased) & Elizabeth Wiseman/Osman. Mary was born c.1834 and died in 1895.
The 1841 census I have found for John fleming -
John Fleming, 30 (about 1811), Born, Lanarkshire, Occ. Carter, Address - Old Vennal.
Elizabeth Fleming, 30 (about 1811), Born, Scotland.
N K (Male), 20, Born, Scotland, Occ. Carter.
I cannot find a definite 1851 census for John Fleming & family. I only know his daughter Mary married in 1856, that there was a witness - Agnes Fleming. Mary had a daughter called Agnes, so I guess the connection to Agnes Fleming maybe that of a sister.
1851 Census (Only one I can find)
John Fleming, 1801, Rennyloanhead, Carter, 45 Shuttle Street.
Mary Fleming, 1807, Montrose
Elizabeth? Nancy Fleming, 1833, Glasgow, Flax Spinner
Agnes??Mary Fleming, 1835, Glasgow, Flax Spinner
John Fleming, 1840, Glasgow, Callenderer's Apprentice
Elizabeth Fleming in -
1861 - born, 1806, Montrose, Forfarshire.
1871 - born, 1808, Montford, Forfar.
Dies in 1877 aged 69, Widow of John Fleming.
So it matches with the info given for 'Mary' in 1851.
I have also found an alternate 1841 census for John Fleming.
John Fleming, 1801, born Lanarkshire, Occ. Carter, Address - 4 G Dow Hill, Glasgow St John's.
Mary Fleming, 1806, born Scotland.
Jean Fleming, 1841, born Lanarkshire.
I don't know if i'm in the wrong County here, or if there is some sort of crossover if the John Fleming with Elizabeth in 1841 and the John Fleming with Mary in 1841 is the same man. I can't find a marriage for John & Elizabeth.