Geomagnetic maps of former Czechoslovakia and Poland and the recently compiled aeromagnetic map of Austria reveal significant magnetic anomalies in the area of the Northern Calcareous Alps and in the North Alpine Foredeep, in the region of the Vienna Basin and in the Western Carpathian Foredeep as well as in the Western Carpathian Flysch. From regional point of view the set of anomalies might be regarded as a slightly sagged belt extending for about 700 km, from Innsbruck to Kraków. Magnetic modelling in association with geophysical and geological evidence imply that this belt is an old basement (Protero-Europe?) conserved between the Hercynian consolidated Bohemian Massif and Alpine-Carpathian zone. Rocks representing the remnants of a North Penninic oceanic crust (especially in the western part of the belt) are considered to be a source of some anomalous structures.