I have found 2 entries in the Register of St Peter, Carmathen
a) 12th Sep 1686 ----- d Johannis Bealth, no name but excellent find for the Bealth name,
Also I found a later enter
b) 30th May 1690 Jane d, John Beth
I am of the opinion Beth is not a family name and that it could be Bealth or even Belth
Does anyone have access to the original film to check on the spelling?