« Reply #11 on: Monday 29 June 15 21:18 BST (UK) »
sorry, haven't spotted them as yet in 1891. If you want to go back before 1871, you'll need to get a copy of the 1870 marriage cert to be certain of Thomas's father.
Mary's family looks to be easier to trace. 1851 census they are good enough to have Jane's mother living with them, so helping back another generation.
1851 Tynykill, Llanwddyn HO107/2499 folio 696 pg 9
John Williams head mar 43 ag lab b. Merionethshire, Llanywrllyn (Llanuwchllyn?)
Jane wife 34
Thomas son 8
Mary dau 5
Catharine dau 2
Jane dau 5
Catherine Jones wife's mother widow 67
all born Llanwddyn except John
Cornwall: Allen, Bevan, Bosisto, Carnpezzack, Donithorn, Huddy, James, Retallack, Russell, Vincent, Yeoman
Cards: Thomas (Llanbadarn Fawr)
Glam: Bowler, Cram, Galloway, James, Thomas, Watkins
Lincs: Coupland, Cram
Mon: Cram, Gwyn, John, Philpot, Smart, Watkins
Pembs: Edwards (St. Dogmael's)
Yorks: Airey, Bowler, Elliott, Hare, Hewitt, Kellett, Kemp, Stephenson, Tebb