Between the inn at Iggesund and Hudiksvall I saw the same violet clay in abundance. I noticed how it formed a layer in the sandy ditches and also observed it on a hillock above a lake that lay immediately alongside. The hillock was 18 feet high, of which humus made up 2 to 3 fingers’ depth, followed by sand of one or two hands’ depth, violet clay of two hands’ depth and, finally, barren sand. Small bivalve shells, white and quite unbroken, lay in this clay; the violet colour, however, when I examined the particles, seemed to me to come from the brown shells that are found in such numbers on the seashore.6