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 mesozoic 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 
eontrary, 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 parts 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 archzan 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 
