As Cummins is my maiden name I know how often it can be corrupted!
1841 Census
Holystone, Northumberland
HO107/830/10/Holystone
John Common, 35
Jane Common, 35
Thomas Common, 10****
Sarah Common, 8
William Common, 6
John Common, 4
Joseph Common, 2
Thomas COMMOM Baptised 24 Feb 1831 Elsdon, birth 2 Dec 1830
Parents JOHN/JANE
(F/S.Org)
1851 John Common is born c 1803 Holystone, Northumberland
At Home are Wife Jane, Children Willy16, Joseph 13, John 2
May be worth following up.
I cant find Thomas 1830 on 1851 Census or any others.