46 RISING AND SINKING OF LAND. [Ch. Y. 



a century before, declared tlieir belief that a gradual change had, for 

 ages, been taking place in the relative level of land and sea. They at- 

 tributed the change to a fall of the waters both of the ocean and the 

 Baltic. This theory, however, has now been refuted by abundant evi- 

 dence ; for the alteration of relative level has neither been universal nor 

 everywhere uniform in quantity, but has amounted, in some regions, to 

 several feet in a century, in others to a few inches ; while in the south- 

 ernmost part of Sweden, or the province of Scania, there has been actu- 

 ally a loss instead of a gain of land, buildings having gi-adually sunk 

 below the level of the sea.^* 



It appears, from the observations of Mr. Darwin and others, that very 

 extensive regions of the continent of South America have been under- 

 going slow and gradual upheaval, by which the level plains of Patagonia, 

 covered with recent marine shells, and the Pampas of Buenos Ayres, 

 have been raised above the level of the sea.f On the other hand, the 

 gradual sinking of the west coast of Greenland, for the space of more 

 than 600 miles from north to south, during the last four centuries, has 

 been established by the observations of a Danish naturalist. Dr. Pingel. 

 And while these proofs of continental elevation and subsidence, by slow 

 and insensible movements, have been recently brought to light, the evi- 

 dence has been daily streng-thened of continued changes of level effected 

 by violent convulsions in countries where earthquakes are frequent. There 

 the rocks are rent from time to time, and heaved up or thrown down 

 several feet at once, and disturbed in such a manner, that the original 

 position of strata may, in the course of centuries, be modified to any 

 amount. 



It has also been shown by Mr. Darwin, that, in those seas where cir- 

 cular coral islands and barrier reefs abound, there is a slow and continued 

 sinking of the submarine mountains on which the masses of coral are 

 based ; while there are other areas of the South Sea, where the land is. 

 on the rise, and where coral has been upheaved far above the sea-level. 



It would require a volume to explain to the reader the various facts 

 which establish the reality of these movements of land, whether of ele- 

 vation or depression, whether accompanied by earthquakes or accom- 

 plished slowly and without local disturbance. Having treated fully of 

 these subjects in the Principles of Geology,^ I shall assume, in the present 

 work, that such changes are part of the actual course of nature ; and 

 when admitted, they will be found to afford a key to the interpretation 

 of a variety of geological appearances, such as the elevation of horizon- 

 tal, inclined, or disturbed marine strata, and the superposition of fresh- 



* la the first three editions of my Principles of Geology, I expressed many 

 doubts as to the validity of the alleged proofs of a gradual rise of land in Sweden ; 

 but after visiting that country, in 1834, I retracted these objections, and published 

 a detailed statement of the observations which led me to alter my opinion in the 

 Phil. Trans, 1835, Part I, See also the Principles, 4th and subsequent editions. 



f See his Journal of a Naturalist in Voyage of the Beagle, and his work on 

 Coral Reefs. 



:J: See chapters xxvii, to xxxii. inclusive, and chap. 1. 



