A study was made of a deposit under a table-shaped drift sand mound. The bog, on a firm B-layer (hardpan), started at the end of the Subboreal period. It was preceded by a fire and stopped by a fire in the Middle Ages, when rye was in cultivation and Centaurea cyanus occurred as a weed. The role of hardpan in depressions of the undulating landscape is discussed, together with the effects of tillage, burning and sodding as factors leading to the shifting of cover sand and the creation of inland dunes.