Praises G. H. Darwin’s letter ["On the geological importance of the tides", Nature 25 (1882): 213–14] which criticises the use made of George Darwin’s views by Robert Ball ["A glimpse through the corridors of time", Nature 25 (1881): 79–82, 103–7]. JWJ argues from the fineness of Cambrian sediments against Ball’s intensification of geological forces. Massive Carboniferous river deltas also contradict Ball’s excessively high tides.