I think your best bet is at class RG12, piece 4432, folio 65, page 36
This is in Garthgynid - an older name for Bedlinog.
The family is at 8 Mount PLeasant
David Williams, 42, colliery engine driver b Cwmbychan, Glam
Ellen WIlliams, 30 b Merthyr
David Jno Williams, 4 b Gelligaer
Levi Tho Williams, 2 b Gelligaer