Hi Lynn
There will probably be more information available on the CDs than there is online.
For Merthr: "Bishops' Transcripts, covering the period (1672-3, 1677-9, 1682, 1686, 1690-1, 1694-9, 1702-3, 1707-8, 1711, 1713, 1715-18, 1723-36, 1738-1800, 1802-39, 1841-2) are at the National Library of Wales, and have been microfilmed by the LDS."
Kind Regards
Morgan