My Mom gave me a book that might interest anyone looking into their South Wales ancestry:
"Pontyclun & Talygarn A History & Topography" written by J. Barry Davies, Trefor I. Rees, and M.A.K. Duggan Published by Llantrisant & District Local History Society.

ISBN: 0-9514330-1-6

The book includes family trees of some of the areas founders and prominent citizens as well as information on ownership and data collected from census info. Also, archived maps.