Till-covered glaciofluvial deposits, presumably eskers, are common in Central Ostrobothnia (Pohjanmaa) within a zone more than 50 km broad, in which no exposed eskers are present. The areal distribution, morphology and stratigraphy of these eskers are described with particular reference to the organic deposits found in many gravel pits within this zone. Some of the organic sediments, such as the Ollala site in Haapavesi, have been correlated with the Eemian Stage, whereas some sites such as Oulainen have been correlated with the Early Weichselian Brarup Interstadial. The Marjamurto site in Haapavesi, described here, probably belongs to the same esker chain as that at Oulainen. It is a freshwater sequence deposited in a kettle hole, and was later buried by littoral sands and till. The palaeovegetation represents an interstadial type of pine-dominated forest. On the basis of its lithostratigraphy and biostratigraphy, the Marjamurto sequence is correlated with that at Oulainen. A preliminary TL date for Marjamurto of 107 ka supports this correlation. The possibility of correlating the 'forested' interstadials of Ostrobothnia with the Early Weichselian Odderade Interstadial is also considered. The Early Weichselian deposits in Ostrobothnia are overlain by only one till unit, as indeed also are the deposits correlated with the Eemian Stage. This suggests that the Weichselian ice spread to southern Finland only once. Thus the tillcovered eskers of Ostrobothnia must themselves date from the late Saalian Stage.

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 of half‐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 the renewal distance (i.e. the distance over which the proportion of a new rock type increases from 0% to 50%). In the Kuhmo area this distance is 16 km.