1861 (name mistranscribed as Margan) : Hafod Olau , living with widowed father and a chap called Robert Rowlands , described as her father's grandson. ( Wrongly , I believe)

answer if mary had a sister, robert would be a grandson

1871 : New Street , Deiniolen/Ebenezer , living with Griffith Morgan (b 1865 ) described as son , and Jane Roberts ( b 1870) , described as daughter . Still with surname of Morgan though .

answer children out of wedlock

transcription errors are down to the registrar they went to ppl's houses to write census record's down