Rivers obey the laws of physics and flow downhill, commonly eroding elevated regions and flowing towards the ocean. Seventy-five years ago, Edelman described the mineralogical character of sediment in rivers in the Netherlands (grain size characterization was described as “unjust”). The data reveal that the mineralogy (and grain size) changes markedly downstream; changes that he interpreted to reflect a North Sea source for downstream segments. He pointed out that rivers in the Netherlands “do not succeed in transporting even one single sand grain to the neighboring North Sea… exactly the opposite… of what inference teaches.” [Although he did not explicitly state it, this dynamic is due to tides in the estuaries. See HERE and HERE for more information.] Edelman suggests that these data “warn us not to apply the pattern-like conceptions of rivers and their sediments…without a critical examination.”
Petrology of Recent Sands of the Rhine and the Meuse in the Netherlands, by C. H. Edelman, Journal of Sedimentary Petrology, August 1938, v. 8, p. 59-66.