2Q4 HISTORY OF GEOLOGY AND PAL/EON TOLOGY. 



negative movements, Professor Suess thinks it impossible to 

 explain them by local ground-elevations; they must be assigned 

 to physical causes of universal significance. 



In addition to the general movements of the water-surface, 

 there have been oscillatory fluctuations of level limited to 

 smaller districts. Local sinking of level is probably due to 

 submarine eruptions or any increase of the deposits on the sea- 

 floor ; or it may be connected with continental denudation and 

 the smaller attractive power exerted on the water by adjoining 

 land. Ascending movements have their origin probably in 

 periodic and alternate heaping of the ocean-water at the Poles 

 or at the Equator, or in local expansion of the water surface 

 under the attraction of newly-formed land or ice masses. 



The tangential folding of the earth's crust, to which Suess 

 attributes the origin of mountain-systems, exerts, in his opinion, 

 only a small and indirect influence on the sea-level. The uprise 

 of continents takes place only as a result of cmst-inthrows 

 and consequent depression of the sea-level. In the upraised 

 land, as the gradients of rivers become greater, the transporta- 

 tion of sediment is likewise increased; enormous masses of 

 material gather close to the coast, and the weight of these 

 depresses the sea-floor, inducing further , positive movement. 

 All the reported facts which might seem to countenance the 

 conception of upheaval of the land are subjected by Professor 

 Suess to careful criticism, and found by him to be for the 

 most part untrustworthy as direct evidence of land movements. 

 In so far as Suess has referred the grander secular movements 

 to subsidence of the water-level associated with crust 

 shrinkage, his results will commend themselves to all students 

 of crust-physics. But his work cannot be said to have 

 arrived at a solution of the causes of local oscillatory 

 movements. Suess himself concludes his discussions with 

 the somewhat mystic-sounding sentence: "As Rama looks 

 across the ocean of the universe, and sees its surface blend in 

 the distant horizon with the dipping sky, and as he considers 

 if indeed a path might be built far out into the almost 

 immeasurable space, so we gaze over the ocean of the ages, 

 but no sign of a shore shows itself to our view" (Das 

 Antlitz der Erde, ii. 703). 



Notwithstanding the strong arguments directed by Suess 

 against secular upheaval of land areas, many geologists believe 

 in an independent upward movement of certain parts of the 



