Question: Are both The Black Cauldron and In Search of the Castaways both based on books by Jules Verne?
Sentence (from "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.
Relevant evidence: Yes