Clontow is probably a small townland in Kilgarvan parish- I can't find it on maps or on the townland index but when I google it Clontoo turns up
see Ad for house property
http://www.daft.ie/searchsale.daft?id=542653
Suggest you get on to the Kilgarvan parish message board on
http://www.irelandxo.com/ somebody there may be able to confirm it.
Regards
annclare