 Areas identified as head include deposits of aeolian origin such as blown sand and loess, slope deposits such as gelifluctates and solifluctates, and recently eroded soil material, called colluvium.With geologists becoming more interested in studying the near-surface environment and its related processes, the term head is becoming obsolete.A related term is 'combe (or coombe) rock', descriptive of a body of chalk and flint fragments contained within a mass of chalky earth typically found on the chalk downlands of south-east England and resulting from freeze-thaw processes.