1889.] THE DISPLACEMENT OF BEACH- LINES. 77 



served with difficulty. And if we suppose the dislocation to be 

 only one millimetre, or still less, it will be quite impossible to 

 prove it. In some countries earthquakes occur almost every 

 day. In Switzerland, for instance, there are in one year about 

 100 earthquakes; in some parts of Japan earthquakes occur 

 every other day. In New Zealand an earthquake in 1848 lasted 

 for 5 weeks, and in some days up to 1000 different shocks were 

 counted. 1 Even in our own country earthquakes are not of 

 very rare occurrence, and some extend from the west coast, 

 right across the country, to the eastern parts. 



It is well known that Scandinavia was upheaved in Post- 

 glacial times. That the land has really risen is shown beyond 

 doubt by the fact that the upheaval was very different in degree 

 in different parts. 



The upheavals and depressions of the solid crust of the earth, of 

 which geology furnishes such numerous testimonies, were no doubt 

 caused by the summing up of the effects of innumerable slight dislo- 

 cations (earthquakes), each of them, in most cases, causing only an 

 imperceptible displacement. As the centrifugal force diminishes 

 daring the lengthening of the sidereal day, by tidal friction, 

 strain accumulates in the solid earth, until the limit of resistance 

 is reached. In higher latitudes there is on the whole a ten- 

 dency to rising, and in lower to sinking. And thus, in the 

 course of time, the effects of earthquakes are summed up, partly 

 in upheaval, partly in subsidence, and such displacements may, 

 after long periods, become very considerable. If a country is 

 e very year upheaved by numerous earthquakes to the extent of only 

 on e or two millimetres, that will in 100000 years cause an upheaval 

 of 100 to 200 metres, and the mean upheaval of Scandinavia in Post- 

 glacial times was certainly not greater than that. This view of 

 the man *er in which continents rise or subside, I have formed in- 

 dependently, but I now see, that it has been propounded, a long 

 time ago, by Charles Darwin, who supports it by the alleged 



l - C pp. 694, 626. 



