So many Llewellyn Jones in Aberdare in 1871! And I can't find Gerrelen on ANY census?!
But this family looks a good match?
Llewellyn is about the right age, and from the right county?
Class: RG10; Piece: 5405; Folio: 57; Page: 14
4 Bwllfa Road, Cwmdare, Aberdare
Jones, Llewellyn Head M 49 Overman b Carmarthemshire
Jones, Ann Wife F 48 b Breconshire
Jones, William Son M 20 Coal Miner b Glamorganshire
Jones, John Son M 18 Coal Miner b Glamorganshire
Jones, Elizabeth Daughter F 12 Scholar b Glamorganshire
Jones, George Son M 10 Scholar b Glamorganshire
Jones, Nicholas Son M 8 Scholar b Glamorgamshire