There is this interesting entry in the IGI, Jane Roberts Jones Or Prichard, Wales Births and Baptisms, 1541-1907, christening:7 January 1827 RHIW,CAERNARVON,WALES father:Robert Prichard mother:
Mary Jones
Could they have just used the two surnames interchangably? Odd that there would be another child using Jones and Prichard from Rhiw