8 A. BLTTT. [NO. 1. 



level have become folded, „bed-thicknesses of 7—8000 feet have 

 become bent as if composed of straw" {Kjerulf: Udsigt over Nor- 

 ges Geologi, Chria. 1879 p. 76). And the folded beds are up- 

 heaved high above their original level. Even such young sea- 

 formations as those of the Eocene epoch, have been upheaved to 

 heights of 21,000 feet above the level of the sea (Suess Antl. d. 

 Erde I p. 564). Sometimes they stand perpendicularly, ore are 

 even reversed so that older strata cover younger ones. Through 

 the fissures eruptive masses have been ejected, and have covered 

 thousands and thousands of square miles. And the division be- 

 tween land and sea alternates. It is true, it has been assumed 

 that the great ocean depths and the great continents have, in 

 all essential respects, retained their original relations to each 

 other from the remotest times, but the beach-lines oscillate pe- 

 riodically backwards and forwards. And these changes in the 

 surface of the earth have taken place from the remotest times, 

 and still remain in activity in our own days. 



Geologists usually seek the explanation in the cooling and 

 contraction of the body of the Globe. The crust becomes folded, 

 just as the skin of an apple wrinkles when the apple dries. 

 The leading geologists of modern days adopt that view, and A. 

 Geikie says in his Textbook of Geology (London 1882 p. 287), 

 certainly with good reason: „With modifications the main cause 

 of terrestrial movements is still sought in secular contraction." 



According to that doctrine, the changes in the crust of the 

 earth depend upon the interior contracting more rapidly than 

 the crust, so that the latter becomes too large, and the force of 

 gravity draws it downwards. In that manner great forces arise, 

 acting horizontally upon the crust, which must thus become 

 folded, and crack in some places. The broken parts fall inwards, 

 and there is thus formed what Suess calls „Einbriiche. u If a 

 part of the crust remains in its old position whilst all around 

 sinks, there is formed what Suess calls a „Horst." 



The old doctrine of forces acting perpendicularly, upwards 

 from the interior, is rejected by Suess in the most decisive man- 

 ner. Both he and Heim have, by their investigations of the 



