While making new geological maps of some parts of the Weser river area, the Holocene of this river and his affluents has been mapped. The flood loam („Hochflut- or Auelehm") could be divided into at least three different formations. The sedimentation of the oldest flood loam begins in each area at different times, but usually it is at work in the second half of the Atlanticum, and ends at the beginning of the Subatlanticum. Two younger flood loams may, on the other side, be principally put into the time about 0 and after 1.000 A.D. The author proposes new technical ideas for the geological mapping of the Holocene of river valleys. He thinks that only after having mapped some more parts of the Weser valley, it will become possible to get an idea about the cause and the significance of the repeated flood loam sedimentation.