PERMANENCE OF CONTINENTS AND OCEANIC BASINS. 129 



stantly used up by the formation of the immense beds of lime- 

 stone which have been deposited from the mesozoie to the pre- 

 sent time. 



Professor Dittmar, in a lecture delivered before the Glasgow 

 Philosophical Society, formed an estimate based upon data 

 given by Boguslawski regarding the solids introduced into the 

 ocean by rivers ; from which he calculated that it would require 

 nearly twelve hundred years to increase the percentage of car- 

 bonate of lime in the ocean by one per cent of its present value, 

 supposing no part of what is added were precipitated by animal 

 life. 



We know that a portion of the Spitzbergen coast is rising, 

 and that some points of the Scandinavian peninsula must have 

 been raised one hundred and fifty metres. Holland, on the 

 contrary, shows a sinking of its shores. Darwin's observations 

 on the elevation of parts of the west coast of South America 

 are well known. I have myself visited the principal localities 

 about Coquimbo, and have found evidence that the maximum 

 elevation probably took place near the latitude of Pisagua, 

 gradually diminishing farther south. We may perhaps regard 

 as remnants of a sea bottom the sloping plains extending from 

 the nitrate beds of Pisagua to the southern j^arts of Chili, par- 

 allel with the Coast Range, until it passes into the Chiloe Archi- 

 pelago. The terraces all along the coast, such as have been 

 noted by Darwin, plainly show the extent of the elevation, or 

 may have been a part of the movement resulting in the separa- 

 tion of the Gulf of Mexico and of the Caribbean Sea from 

 the Pacific. 



Let us examine a geological map of North America. We 

 see that, during the earliest geological times, (Fig. 62) the 

 North American continent was indicated in its broad outlines 

 by a great telluric fold, — an immense V-shaped archaean con- 

 tinent, situated mainly in British North America, one arm 

 reaching northeastward to Labrador, and the other northwest- 

 ward from Lake Superior. In addition to this continental nu- 

 cleus, smaller mountain ranges — the Rocky Mountains and 

 Appalachian and other isolated areas — existed, indicating the 

 presence of a submarine American plateau, upon which the 



