I've found Thomas Owen Jones's parents's marriage entry in Llansilin - your 5x great grandparents
Feb 8th 1839
John Griffiths, full age (i.e over 21), bachelor
occ - Parish Clerk
Residence - Llanrhaiadr yn Mochnant
Father - David Griffths, Parish Clerk
and
Jane Jones, full age, spinster
Residence - Golon Isaf, Llansilin
Father - Edward Jones, Groom
Both signed.
Witnesses - Thomas Owen Griffiths* and Ann Roberts
Could this be a brother of John's?
Gadget