40 MOUNTAIN AND MOORLAND 



tracts are especially unstable, and there "protracted 

 spasms of mountain-making" have repeatedly oc- 

 curred mountain-making which results in the Fold 

 mountains and Block mountains, Bosses and Vol- 

 canoes, to which we have briefly referred. It must be 

 understood that mountain-making is one of the most 

 difficult of subjects, and what we have said does not 

 go very far. We hope, however, that it is true so far 

 as it goes. It is time now to pass to those mountains 

 which originate in a way radically different from those 

 we have hitherto studied. 



DIAGRAM OF CARVED-OUT OR RELICT MOUNTAINS. 



The lower zones are undisturbed sedimentary rocks. On these 

 rests a plateau of accumulation, originally up to the level of 

 the dotted line, which now represents the summits of the 

 higher mountains. 



When is a mountain not a mountain? When it is 

 the remnant of a much-weathered plateau or Block 

 mountain. It has not been uplifted, in its present form 

 at least ; it has been carved out by weathering agencies 

 the rain, the frost, the glacier, the avalanche, the 

 landslip, the torrent, the heat of the sun, the wind- 

 blown sand, and the air itself. Such mountains are 

 called Subsequent, Relict, or Residual, and we may 

 almost say " Carved-out." They differ fundamentally 

 from Original or Tectonic mountains, which we may 

 almost call "True mountains." 



As Professor Geikie says: "They have not been 



