Late-Quaternary alluvial deposits in Mediterranean valleys have been divided into "Older" and "Younger" Fills. The Older Fills are generally coarse, are commonly calcreted and may be associated with isolated Palaeolithic artefacts of uncertain provenance. In broad terms the Older Fills were clearly deposited during colti stages of the Pleistocene. However, it has rarely proved possible to establish a more precise dating and correlation with specific Pleistocene stages, or a more precise identification of depositional environments and their relationship with, and impact on, human activity and land-use. The Voidomatis River of north-west Greece contains four main alluvial terraces which can he distinguished by lithological and mineralogical techniques. One of these, the Aristi unit, can he directly linked with glacial deposits in the headwaters. Comparison of dates for the Aristi unit with dated evidence of late Upper Palaeolithic sites in the lower reaches of the river gives a basis for assessing the impact of alluvial history on the Palaeolithic occupation of the area.