344 



J. D. IVES 



in the lower limit of mature detritus in Sweden is related to rock type rather 

 than vertical extent of glaciation and that mature detritus undoubtedly exists 

 in areas proven to have been completely inundated during the last glaciation. 

 The controversy of the mode and time sequence of development cannot be 



?«-. . 



Fig. 5. Mature moumain-top detritus above JOOO m in the Kaumajet Mountains. 



Note the small gneissic erratic in the foreground indicated by the arrow. {Photo 



by R. F. Toinlimon, July 1958.) 



examined exhaustively within the limits of the present paper. Suffice it to say 

 that in northern Labrador, where rock type is relatively uniform and almost 

 universally Archaean, it is altitude, and therefore vertical extent of glaciation 

 which is the important dominant, rather than rock type. It is urged, therefore, 

 that until evidence is available to the contrary, the surfaces which carry 

 mature detritus have been subjected to sub-aerial weathering for a far longer 



