Florence McCarthy appears lots in my branch of the McCarthy clan as Florence Dennis, Florence John, John Florence etc etc. We are the McCarthy Reagh branch of the family. There are McCarthy Mor, McCarthy Reagh, McCarthy Dunmanway, McCarthy Sowney etc - some of these are earlier & some later offshots of the original ancestor. There is a shared common ancestor found by DNA research at about 400AD. See the McCarthy DNA project if you have a intact male line.
Google a famous Florence McCarthy who was a political prisoner of Queen Elizabeth I in the 1600s & died & is buried in London.
Please visit my PUBLIC tree 'Josephine Salt Family Tree Halloween 2012' to see if your McCarthy are the same as mine.