THE THROES OF THE CONTINENT. 265 



ward, to distances not yet ascertained. This was the Great 

 CordiUeran Land. There were probably other small land 

 areas, rising like islands from the universal ocean ; and there 

 may have been other areas of moderate continental extent; 

 but, so far as our probable knowledge goes, the three con- 

 tinental expanses mentioned were the chief beginnings of North 

 America. 



Simultaneously some of the north-eastern portion of South 

 America was land; and perhaps, also, a part of the region 

 now occupied by the West Indies. Some portions of the 

 British Islands were also land ; and this stretched across the 

 North Sea into Scandinavia. Most other parts of the world 

 were sea-bottom. 



The CordiUeran Land was a great mountain system, dis- 

 playing lofty ranges made of crumpled strata ; enormous prec- 

 ipices, the result of mechanical dislocation; and finally, a 

 type of mountain sculpture, of such broad, smooth forms as 

 to warrant the belief that subaerial erosion had never carved 

 and furrowed the mountain flanks with the sharp ravines 

 characteristic of modern mountain topography. This massive 

 belt of Eozoic cordilleras determined the limits of the mod- 

 ern cordilleras, and very much of the details of their funda- 

 mental structure. 



Such was America in the twilight of its history. There 

 must have been, however, as I have argued in Talk XXXTX, * 

 some lands which had now disappeared. These surviving 

 germinal nuclei are composed of stratified rocks. Older rocks 

 had been reduced to sediment in supplying material for the 

 building of the lands which are the oldest now remaining. 

 Let us see what vicissitudes these lands were destined to un- 

 dergo. 



The first seon of the ocean's history was past. With the 

 opening of the second, nearly the whole of the CordiUeran 

 Land began to subside. It sank until only the mountain 

 masses rose as rugged islands above the sea-level. Only the 

 western border held its position. This remnant of the Cor- 

 dilleran Land stretched along western Nevada and eastern 



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