The Lake Edgar Fault originally formed in the Cambrian as a sinistral wrench fault with a displacement of.
2.
It is bounded by dextral wrench faults ( possible transform faults ) and probably represents a pull-apart basin.
3.
The trace of the North Pyrenean Fault becomes more and more diffuse west of Lourdes; near the Basque basement massifs, it seems to be displaced to the south by a wrench fault and then possibly continues into Spain south of the " Basque Marble Nappe " and south of the " Basque Fold Belt ".