1889]. THE DISPLACEMENT OE BEACH-LINES. 29 



places. It is also a probable assumption that the crust has not 

 everywhere the same power of resistance to the inward strain, and 

 that the plastic mass must be forced upwards, especially, under 

 the more yielding parts of the upper surface. We meet with a 

 striking instance of this in the Laccolites of North America. 

 The erupted matters are here pressed upwards from the deep, 

 and have upheaved the beds into a cupolar vault, in such a 

 way that the upheaval has varied in degree in the different 

 parts, and is greatest in the middle of the cupola. We may 

 suppose that similar forces, although it may be on a much greater 

 scale, have contributed to the upheaval of Scandinavia, that 

 Scandinavia is, sit venia verbo, like a laccolite on a gigantic scale. 

 We must, besides, remember that the alterations in the surface 

 of the Earth, that have taken place in the tertiary and quarter- 

 nary periods, however great they may to our vision appear to 

 be, are yet slight in proportion to the whole terrestrial mass; 

 and small forces acting on a great mass may produce quite 

 considerable local effects, in the event of the changes not taking 

 place everywhere on the same scale. If we suppose that the up- 

 heaval has, in this manner, not everywhere been equally great, 

 then a lowering of the equatorial belt, of only a couple of metres, 

 would be sufficient to cause many such countries as Scandinavia 

 to be upheaved many metres, and there would still remain 

 reserves of force not expended or exhausted. 



It is of course not asserted that Scandinavia must be up- 

 heaved, always to the same extent every time the eccentricity 

 has attained a high value. If the upheaval has been great in 

 a given time, it is likely that the ensuing period of upheaval will 

 have more difficulty in elevating the already previously upheaved 

 land. The situation of the weakest points will change. Next time 

 the upheaval will perhaps preferably act in other regions. If we 

 consider the tertiary formations of Europe we find that the 

 series of layers is nowhere complete. Only when we combine 

 all the layers formed at different places do we obtain a com- 

 plete profile. The reason of this is, certainly, partly owing to 

 the changes in the form of the Earth not having taken place 



