IN THE DEGRADATION OF THE LITHOSPHERE. 397 



stony portion of the earth passing into complete disintegration 

 under the combined action of a great system of jointing which has 

 already broken down the coherency of the mass, and under marine 

 transportation ( erosion ) . 



It is my expectation in a later paper to present further results 

 of the study of this locality. 



From the discussion given, there may be deduced, then, the 

 following propositions : 



Proposition lo. — That the lithosphere has certain constant phys- 

 ical factors which act universally and independently of local surface 

 conditions : one of these is, for example, igneous action, and an- 

 other is jointing. 



Proposition ib. — That this jointing develops as an essential re- 

 sult from the nature of the lithosphere itself which shows in prac- 

 tically all cases from continental masses to loose sands the regu- 

 larity of lines of weakness. 



Proposition 2a. — That surface features of the lithosphere, both 

 sub-atmospheric and sub-oceanic, are controlled not by the agents 

 of the atmosphere nor hydrosphere, but by the distribution of lines 

 of master and minor joints. 



Proposition 2h. — That surface drainage, glaciation, variations 

 of weathering, may be regarded as accidental; that behind all of 

 them, and also running ahead of them as the essential controlling 

 factor, is jointing. 



Proposition ?. — That joints have been present throughout all 

 the geological history of the lithosphere, considered as possessed of 

 solid portions. 



Proposition 4. — That in the development of continental outlines, 

 including continental shelves, and also in the development of sur- 

 face continental features due to weathering and to atmospheric and 

 marine erosion, the controlling factor is not atmospheric nor climatic 

 nor marine primarily, but is due to the fundamental nature of the 

 lithosphere itself as shown in its lines of jointing. 



Proposition 5. — That the " repeating patterns " of authors which 

 show joint control of the lithosphere on the continental surfaces 

 may, with equal truth and value, be applied to the interpretation 

 of the sub-oceanic lithosphere and that the distribution of oceanic 



