We report by the first time the finding of scapolite-bearing marbles in the Southern limb of the Biscay Synclinorium (Basque-Cantabrian basin). Marbles are found as layers or fragments in Triassic evaporites. I. Evaporitic rocks an antiform cut acrossby crop out in transversal faults. The presence of such marbles lead us to propose a new location for the prolongation of the North Pyrenean Fault in western sectors of the Basque-Cantabrian bassi