Are both The Black Cauldron and In Search of the Castaways both based on books by Jules Verne?
The Black Cauldron (film):  The 25th Disney animated feature film, it is loosely based on the first two books in "The Chronicles of Prydain" by Lloyd Alexander, a series of five novels that are, in turn, based on Welsh mythology. In Search of the Castaways (film):  The film was directed by Robert Stevenson from a screenplay by Lowell S. Hawley based upon Jules Verne's 1868 adventure novel "Captain Grant's Children".
no