CRUST-MOTIONS. 59 



of Spitzbergen, as described by Mr Lament and other recent 

 visitors; to the ancient shore-lines of Siberia, as amply illus- 

 trated by Von Wrangell ; the numerous terraces of uprise 

 noticed by Dr Kane and other Arctic voyagers on the coasts 

 of Greenland and the Arctic islands; the terraced shores of 

 Patagonia, long since observed by Mr Darwin ; as well as 

 to the less distinct, because more ancient, shore-lines that 

 encircle our own islands and the opposite coasts of France 

 and the Spanish Peninsula. As with these uprises, so also 

 with several depressions that have been noticed, though 

 these from their nature are generally less perceptible. Such 

 tracts of subsidence have been observed along the west 

 coast of Greenland, the southern coasts of the United States, 

 and generally in the basin of the South Pacific. Whatever 

 the nature of these uprises or depressions whether at the 

 rate of four or five feet a century, as in the case of Scandi- 

 navia, or with greater or less rapidity ; whether recent, like 

 those of Spitzbergen and Greenland, or ancient, like those 

 of our own country they all belong to the same class of 

 phenomena, and are evidently the result of some great but 

 unknown law. Physicists have attempted an explanation, 

 some attributing the phenomena to oscillations of the hypo- 

 thetical molten interior, and others to secular expansions 

 and contractions of portions of the crust, as arising from 

 changes in the axis of rotation and centre of gravity. In 

 either case the oscillation of a few thousand feet is insigni- 

 ficant as compared with the diameter of the globe ; and as 

 elevation in one region seems to be counterbalanced by sub- 

 sidence in another, the general relations of our planet may 

 be regarded as standing for ages unaffected by the amount 

 of its superficial changes. 



Insignificant, however, as ' may be the effect of such 

 oscillations upon the general relations of the earth, they are 

 all-important to the climate, and consequently to the flora 



