Instead of the theory that ice-pushed walls are formed through horizontal pressure by the Saalien glacier (bulldozer-effect), it is suggested here that it was vertical pressure of the ice-mass what caused imbrication and overthrusting of pre-glacial sediments. After general information about the formation of the delta, the stratigraphy, the sedimentary petrology, and the geographical distribution of the formations, the basic tectonics are described. The article ends with a description of the Municipal Sand-and-gravel pit near Hattem (Central Netherlands). Attention is given to the tectonic and sedimentological features, with emphasis on the different behaviour of the clay-rich subtidal Tegelen- and the sandy fluviatile Enschede-Formation