222 F. B. TAYLOR ORIGIN OF THE EARTH's PLAN 



any one else for an explanation of the causes of displacement of strand- 

 lines and of mountain making. But Suess does not undertake to ex- 

 plain. He is content to make only very brief and apparently tentative 

 suggestions concerning the nature of the causes. 



It is interesting to observe that after relying upon eustatic negative 

 movements through nearly all of part iii of "The Face of the Earth'' to 

 account for displaced strand-lines, Suess turns in the closing pages of 

 that part to a very different cause, where he says : 



"Movements like these, which present themselves as oscillations, and extend 

 around all coasts and under every latitude in complete independence of the 

 structure of the continents, can not possibly be explained by elevation or sub- 

 sidence of the land. Even as the transgressions of the ancient periods are 

 much too extensive and uniform to have been produced by movements of the 

 lithosphere, so, too, are the displacements of the strand-line in the immediate 

 past" (IL550). 



After rejecting Adhemar's suggestion of an alternating accumulation 

 of water at each of the poles, he observes : 



"As far as we are in a position to judge, it appears much more as if that 

 which characterized the more recent movement was an accumulation of water 

 toward the equator, a diminution toward the poles, and as though this last 

 movement were only one of the many oscillations which succeed each other 

 with the same tendency — that is, with a positive excess at the equator, a nega- 

 tive excess at the poles. 



"Negative traces are to be seen in all latitudes. We may attempt to ex- 

 plain them by means of eustatic negative processes — that is, by great sub- 

 sidences ; but this would presuppose n uniform sinking of the sealevel to the 

 extent of more than 1,000 feet in quite recent times. It is much more prob- 

 able that the negative traces at considerable altitudes in the tropics are not 

 of the same age as those in high latitudes, and that an accumulatioti of water 

 occurs alternately at the poles and the equator. Among these traces there 

 may be one or more of a eustatic negative origin, but if so. we have not yet 

 learned how to distinguish them" (II, 551). 



Thus, although he had relied in earlier chapters almost exclusively 

 upon subsidence as the one great agency of change in the earth's history, 

 Suess seems constrained to admit in the last analysis that most of the 

 displaced strand-lines appear to have been caused by an independent 

 oscillatory movement of the ocean. Suess calls this movement an oscil- 

 lation; but what kind of an oscillation is it? He answers this question 

 clearly enough, where he says that "an accumulation of water occurs 

 alternately at the poles and the equator." 



The present figure of the ocean is that of an oblate spheroid — a 

 spheroid having a certain degree of oblateness which is roughly ex- 

 pressed by the fact that the polar diameter of the globe is 26 miles 



