10S E. Suess — Paleogeogrwphy of North America. 



All measurements of the polar applanation of the globe are 



executed on the hase of the actual strand-line. The result of 

 these measurements therefore, does not represent the ap- 

 planation of the lithosphere but of the hydrosphere, and the 

 nigh terraces or strand-lines in high latitudes prove the vari- 

 ability of the hydrosphere's shape. It is very improbable that 

 the quantity of water has greatly increased, and this increase 

 was probably not more than the volume of juvenile waters 

 issued by volcanoes. 



The terraces of the north are very distinct, as well as those 

 of a great number of islands in' low latitudes of the Pacific; 

 but I cannot with certainty see whether these two sets of 

 phenomena are synchronous and continuous or complementary. 

 I believe in the formation of negative eustatic strand-lines 

 through the sinking of ocean bottoms ; therefore 1 suppose 

 them to he synchronous. Rotation would give complementary 

 lines (better complementary phases, as plus in polar regions 

 and minus at equator), but synchronous negative lines might 

 interrupt them. 



What I wrote in 1883 about the considerable attraction of 

 the continents and islands on the adjacent waters was then 

 regarded as fully ascertained by our first authorities. Later 

 on doubts arose and the question seems not yet fully settled. 



Nature is parsimonious on occasions in allowing us to follow 

 the actual facts in arctic, antarctic and in tropical regions. 

 What Ave know is principally the northern temperate zone. 

 In Mesozoic times the American and the Euro-Asiatic-Arctic 

 transgression seem to bo different. Of real peri-arctic trans- 

 gression, that is, actual heaping of water about the north pole, 

 the last inundation (Champlain) offers most proof and still 

 holds as the best evidence for a rotatory hypothesis. On the 

 other hand, the sharpness of all negative lines speaks decidedly 

 against their formation by rotatory phenomena. Therefore I 

 accepted the formation of the elevated strand-lines as due to 

 the making of new depths, and left the cause of transgressions 

 in doubt. Even now I cannot go farther. 



I must close. Writing to a fellow geologist from whom I 

 have learnt so much is such a treat to me that I must beg you 

 to forgive the great length of this letter. What I offer you is 

 little more than a number of questions ; but questions are the 

 buds on the tree of knowledge. 



