Till lithology and transport distance were studied along five transects running in the direction of ice flow and intersecting the N‐S‐oriented Kuhmo Greenstone Belt, which is some 5 km in width. A total of 531 stone counts were performed on three fractions (>20 cm, 6–20 cm and 2–6 cm) in 162 pits dug with a mechanical excavator. An experimental model is developed for predicting the transport distances of clasts in basal tills. It shows the traditional method of expressing transport in terms ofhalf‐distance(i.e. the distance at which the proportion of a given rock type in the till has been halved from what it was at the distal contact of a given rock type in the bedrock) to be dependent upon the width of the source unit in the bedrock, varying in the present case from 0 km to 16 km as the width of the source belt increases from 0 km to infinity. The Kuhmo Greenstone Belt being 5 km broad, the mean half‐distance for the transport of stones and boulders in the till is 2 km, the boulders having been moved somewhat shorter distances and the pebbles longer distances. It is recommended that transport distances for till material should be expressed in terms of therenewal distance(i.e. the distance over which the proportion of a new rock type increases from 0% to 50%). In the Kuhmo area this distan