Meer over oude rivierlopen naar en in Nederland.

Data gathered by the author from old and more recent publications lead, when taken together with some observations by the author, to surprising conclusions with regard to the problem of the old river courses towards and in the Netherlands. These conclusions fallow here below. 1. In the Upper Pliocene and the Lower and Middle Pleistocene time the whole Baltic Sea region was land. At least two rivers flowed from there to the Netherlands; certainly one of them became Günz Glacial a meltwater stream. With the end of the latter the wohle direct fluvial transport from the Baltic region to the Netherlands ceased. 2. The rivers in north-west Germany have not been temporarily defected towards the West when the Mindel - resp. Riss ice-sheet blocked their supposed former normal northerly course, but their topographically determined normal drainage to the West is during the Riss - and the Würm time diverted towards the north by headward eroding ice-marginal streams. 3. After considerable activity in the Upper Pliocene time, both Elbe and Weser became placid rivers, the mountain valleys of which were filled up to a considerable extent. Not until the mindel glaciation start there again a long period of vigorous erosion in the higher courses with rapid sedementation in the lower reaches. 4. The Weser-Elbe material transported to the Netherlands during the mindel regression phases and possibly till in the Riss preglacial time, contains besides glacial components much reworked Lower Pleistocene Sediment picked up from Kaolin sand deposits in n.w. Germany. 5. The „Potklei" (German: Lauenburger Ton) and the fine sands alternating with it was largely deposited in Mindel to Mindel-Riss times. In the course of the Riss preglacial time the attact by erosion of the Rhine-Meuse- and the Weser-Elbe Sediments in the Netherlands started, and of those of the Potklei too. 6. Rhine and Meuse appear to have already reached the middle of the Netherlands during the older Günz or Donau glaciation. Their gravel is found there mixed with that of the Baltic rivers and with some components dirived from carboniferous and Younger Strata in the nearest part of Germany. The Sand from this mixture is however not brown like that from Rhine and Meuse but white like that from the Baltic region.