About Callaghan:
http://genealogy.about.com/library/surnames/c/bl_name-CALLAGHAN.htm About Sisley:
http://shop.store.yahoo.com/4crests/surmeanps.html Sisley is apparently a surname taken from the firstname Sisley.
Compare: other variant of this surname are: Siseley and Sisseley. (very similar to Cecily). I tried to look of it was possible that
ley would mean 'clearing', but there seems to be no such meaning of the surname Sisley. I also tried to see if it was related to the island Sicily, but Sisley is not stated as an English derivative of Sicily. So, Sisley is a matronymic surname (meaning it is derived from of a female name).