The authors measured resistivity at various depths during the sedimentation of kaolinite in different ionic concentration fluids. They attributed a decreasing resistivity (increasing conductivity) with time in the low ionic concentration fluids to decreasing tortuosity. The authors suggested that the initial structure is a card-house, which changes to an aligned structure with time, thereby decreasing the tortuosity. The purpose of this discussion is to provide complementary information and an alternative hypothesis that may help with the interpretation of these types of studies.