370 THE PLAN OF THE EARTH AND ITS CAUSES. 



America, Australia, Greenland, and the Antarctic continent, and the 

 Pacific, Atlantic, Indian, and Arctic ocean depths, as we know them at 

 present," were all marked out in the primeval gaseous nebula. These 

 gaseous continents condensed to liquid continents, marked oft' from the 

 suboceanic areas by chemical differences; and these liquid continents 

 were fixed as the solid continents, heightened by shoaling as the molten 

 globe and its last lava ocean solidified. 



That theory appears probable with one verbal amendment — the sub- 

 stitution of the term " archrean blocks" for continents. That these 



Fig. 3. 



THE MOUNTAIN SYSTEM OF CENTRAL AMERICA. «, VOLCANIC CHAIN OF HEREDIA; &, SIERRA CANDELLA; 

 C, CORDILLERA DE DOTA ; d, SIERRA CHIRIQUI; e, SIERRA VERAGUA; /, CORDILLERA DE SAN BLAS; g, 

 VOLCANIC CHAIN OF ALAJUELA. 



archsean blocks — the earth's great corner stones — were embryonically 

 outlined by chemical segregations in the molten or gaseous stages of 

 the earth seems probable. But these archaean corner stones, though 

 the foundations of the continents, are not the continents. Lord Kel- 

 vin's theory suggests no explanation why chemical segregations should 

 have assumed the shapes of the continents, so that his explanation 

 rests on an unexplained cause ; and even if his theory be amended by 

 application to the archtean blocks instead of to the continents, the 

 theory is geographically insufficient, as it does not show the relation 

 between the archeean blocks and the existing continents. 



