High-pressure volcanic-arc granulites, N-MORB eclogites and shallow crustal volcanosedimentary high-pressure gneiss units occur in the high-pressure metamorphic fold-nappes and ductile thrusts that make up the Cabo Ortegal upper allochthons. Confluence of units from such disparate tectonic settings occurred at an eo-Hercynian convergent plate margin, that in this case, involved oceanic, arc and continental lithosphere. We argue that the sheath-like form of the fold nappes and the mineral and stretching lineations defined by high-pressure mineral assemblages subparallel to fold axes depict the internal organization of high-pressure sheets at deep tectonic realms of an oblique subduction/collision orogenic channel