I know it's late (only just got home from holiday) but it doesn't seem that anyone has sent you the requested words. Did you want...

O dyma enw'r feinwen
Sydd yn codi gyda'r seren
(X 2)
A hon yw'r washael fawr ei chlod
Sy'n caru bod yn llawen.

Which was often followed by...

Hyd yma bu'n cerdded
Gyfeillion Diniwed,
(X 2)
A phawb yn ymddiried cael canu.

Os eithoch yn gynnar
I'r wely'n ddialar
(x 2)
O codwch i'n hawddgar roesawi.

These two were collected by Maria Jane Williams in the last century and there are full historical notes in the Welsh Folk Song Society reprint of her collection *Ancient National Airs of Gwent and Morgannwg*.

Hope this is helpful?

Sian