The last 20 years or so have witnessed a growing number of papers reporting the occurrence of thick mantles of weathering residuals in northern mid- and high latitudes and linking them with landforming processes. In particular, purportedly bare shield areas within the extent of Pleistocene glaciations have been shown to retain an extensive saprolitic mantle whose thickness may well exceed 20 m. Characteristic landform assemblages of residual hills, tors and boulder fields, undulating plateaux and rock-cut basins are interpreted as products of selective deep weathering that has been exploiting various lithological and structural differences within bedrock, hence essentially as an exposed weathering front. The notion 'etchsurface' gains modest popularity and etched landscapes are now described from as diverse areas as Central Europe, the British Isles, Fennoscandian Shield, Iberian Peninsula and Laurentide Shield of North America.

A question arises if the saprolites and associated landforms are relicts of tropical millieu of the Mesozoic and Palaeogene, as has often been claimed, or whether they illustrate the principle of convergence in different morphoclimatic zones. Indeed, it has been demonstrated that many of the thick saprolites and etched landforms are of Cretaceous and/or Palaeogene age, whilst an independent evidence exists for warm and predominantly humid environments at that time. However, it needs to be emphasised that much of the Mesozoic and Palaeogene were protracted periods of tectonic calm, thus additionally favouring weathering profile deepening. The most important finding is the recognition of regionally extensive deep weathering of sandy and grus type in the geological record of the rather temperate Neogene. These saprolites, although geochemically 'immature', may attain 10 m or more in thickness and mantle tor-like bedrock projections and boulders. Sandy weathering is likely to proceed at a relatively fast rate and efficient denudation leads to the exposure of a new generation of etchsurfaces that bear no relationship to their much older, 'tropical' counterparts. It may be proposed that tropical conditions are not necessary for the phenomenon of deep weathering to occur and etched landforms to form, although the exact type of weathering, mechanisms of stripping and resultant relief seem to differ between tropical and temperate environments.