vallescura rule
Vallescura rule. Maritime law. The holding that when a maritime loss is due to more than one cause, and the carrier is exempt from liability for at least one of them, the burden is on the carrier to prove what loss is due to the exempt cause or else be liable for the entire loss. Schnell v. The Vallescura, 293 U.S. 296, 55 S.Ct. 194 (1934).