Premise: The Musee de Dieppe, also known as the Ceteau-Musee, in the 15th-century chateau in the Rue de Chastes, has a good collection of model ships and carvings in ivory, dating from the 18th century when elephant tusks were a major import from Africa and Asia.

Hypothesis: Elephant tusks were a major import in the 17th century.
Relation: contradiction