of spelling variations in Scottish names. Caudill has been spelled Caldwell, Coldwell, Caldwill, Cauldwell, Cauldwill, Cawldwell, Guildwell, Calewell, Caldewell and many more. First found in Renfrewshire , at the Caldwell Tower, a mansion and old estate that dates back to 1294. The current Caldwell Tower stands on a mound, and is