412 A. Blytt on the probable Cause of 



tions, the opposite condition occurs, the sum of the positive 

 movements preponderates. Further toivards the south, beyond 

 25°-35° south latitude, the terraced land of the north begins 

 again in South America, South Africa, South Australia, and 

 Neiv Zealand, i. e. the same preponderance of the negative 

 movements, with the same oscillating* character as in the 

 north." The exceptions (accoi'ding to Suess) are few and of 

 little importance. 



Howorth and Suess have therefore both come to the same 

 result. Buttheir explanations are directly opposite. Howorth 

 thinks that it is the land which has risen under higher lati- 

 tudes; that the earth, as it were^ swells up towards the poles 

 and contracts under the tropics. Suess, who will not admit "^ 

 any other elevations than those which are the consequences \ 

 of foldings, is of opinion that it is the sea which has flowed ' 

 towards the lower latitudes. He indicates as a possible ex- 

 planation changes in the length of the day and the centrifugal 

 force. But this change should then only have acted upon 

 the sea, and therefore, since the sea has flowed towards the 

 equator, the day should have been considerably shorter in the 

 last geological period. We shall see hereafter that there is no 

 known cause which could have produced such a shortening of 

 the Sidereal day as would serve to explain what Suess wants to 

 explain. The old theory of refrigeration is scarcely fitted 

 to explain these conditions indicated by Howorth and Suess. 

 Even Suess, who is a zealous adherent of the theory of con- 

 traction, is obliged here to seek for another explanation. 



Another theory, however, has come forth in our day, a 

 theory which, no doubt, is destined to play a great part in 

 geology. It is derived originally from the celebrated 

 philosopher J. Kant. In 1754 he wrote a memoir entitled 

 " Untersuchung der Frage : ob die Erde eine Veranderung 

 ihrer Achsendrehung erlitten habe ? " In this it is shown "1 

 that, by reason of the attraction of the moon and sun, the sea 

 is constantly in a movement opposite to the daily revolution of 

 the earth. The friction of the tidal waves against the bottom 

 and coasts of the sea diminishes the force of the axial 

 revolution and works constantly in the same direction, so ; 

 that the sidereal days must for this reason always become 1 

 longer and longer. The moon always turns the same side 



* Witli this word Suess alludes to the circumstance that the coast- 

 lines and terraces occur at various levels one above the other. He 

 thinks that each of these levels indicates an oscillation of the sea. I 

 believe that the greater part of these levels are merely a consequence of 

 climatic changes due to the precessions. (See Forh. Vid. Selsk. Christ. 

 1881, No. 4.) 



