In a paper in the Phil. Mag. for March, 1864, “On the Formation of the River and other Valleys of the East of England,” I endeavoured to show by the aid of a rough map that the whole of the hill and vale system of that part of England which lies east and south of a line drawn from the Humber to the Cotteswold Hills originated in a series of concentric arcs spreading from two centres, one of which was near Canterbury, and the other just south of the western end of the Isle of Wight; the features thus produced having been rendered more apparent by the denudation to which the disturbances gave rise, and to which both at the time, and subsequently also, these gave direction.