Joyce
Having no father stated on your birth certificate usually points to illigitimacy. Having
read your email it seems the 1871 census states for the Davies family you mention that a
William Davies listed as a brother to Mary as you quite rightly say, but that both William
& Mary his sister are both unmarried, so in fact all 4 children were all born out of
wedlock. I cant find this family on the 1861 census but it could be because there are
several thousand people missing in this area from the census due to the census being
lost.
However I did find a family in Llanelly Breconshire in 1851 that could the family of
William & his sister Mary. Parents were Thomas & Elizabeth aged 49 & 50 born
Bedwellty & Goytre Monmouthshire. The aged of William & Mary have a 2yr difference
to 1871 which is neither here or there, but there birthplaces are the same, his being
Llanelly Brecs and hers being Aberystruth.
Mike