The west-east-directed part of the Penninic ocean basins, with their associated intraoceanic rises of the Alps and the western Carpathians, is considered as a complex Jurassic-Early Cretaceous transform zone that links the northern end of the Piemont-Ligurian ocean with the northern end of the Vardar ocean. The Maghreb transform belt may furnish an analogous example. Several traverses through the Alps are briefly described. Correlation between the Penninic zones of the Western and Eastern Alps is still controversial.