The Welsh Patronymic probably died out before the records began to be written down. A quaint way of linking families was to name a family after an animal. A Porthcawl headmaster whose family came from around St Davids wrote that his family were the foxes. As for mine, they were the Pembrokeshire pigs.
I made a tree in excell of Ruth Madocs line and the Snow lines, if your interested. My distant interest is in a cousin by the name of John who claim to be related to Lloyd George.