Just for clarification for anyone who reads this: there are many, many variants of these surnames. I have seen it spelled Carl, Carll, Carle, Corl, Corll, Cairl(l), Carroll, and that is just a sampling of the possibilities. There are Carl/Carll/Carles in most states of the union, and in the UK, Germany, France and Italy also. It is definitely not distinctive to Michigan!