Crystalline, volcanic and sedimentary boulders in the main and middle terraces of the Rhine west of Krefeld

the main terrace deposits of the Rhine, spread between the Süchtelner Höhenzug and Viersen-Boisheim, have been repeatedly found in the past few years at site ascents of crystalline, vulcanite and sedimentary rocks. They confirm previous findings that have been made in various places in this region since the beginning of the 20th century. The occurrences of the crystallised stones are partly more than 20 km away from the Saale-era ice rim, which stretched between Krefeld and Nijmegen (Netherlands) over a length of about 70 km and is now characterised by partly powerful moorings and their sander. Due to their great distance from the edge of the moraines, e.g. the Schaephuysen mountain range, the crystal stones can therefore hardly be regarded as glazifluviatile relics of a saale-time sander. ...For the vulcanite and sediment angers as well as for much of the crystal stones found in the main terraces, only a southern origin from the catchment area of the Rhine is considered. ...