84 A. BLYTT. [N0.1. 



to such a degree that, after the expiry of 100000 years, the 

 day is lengthened ten seconds. In that calculation no heed 

 is paid to the „bodily tides", supposed by G. Darwin to act 

 on the plastic mass of the globe. If we reckon with only the 

 above named 10 seconds in 100000 years, then to this lengthening 

 of the day there corresponds a shortening of the equatorial radius 

 of 5.6 m. and the double prolongation of the polar one, 11.2 m. 

 If, now, we suppose the solid crust to lie undisturbed for 1) mil- 

 lions of years, which is the time corresponding to a geological 

 cycle, we have a strain accumulated, corresponding to an 

 upheaval of the polar tract of 168 m. and a subsidence of the equa- 

 torial belt of 84 m. In this manner, even if the above named value of 

 the retardation should be too high, very great and extensive uphea- 

 vals and subsidences may take place in a relatively short time, when 

 strains accumulated through long periods are eventually released, f 

 The great transgressions of the sea in higher latitudes, may j 

 also be explained by the hypothesis. We must suppose, that 

 in the times of transgression the solid earth had come to depart 

 much more from the figure of equilibrium than at other times. 

 During such periods the strain which afterwards caused the 

 great upheavals, was accumulating. As the centrifugal force 

 steadily diminishes, the sea always rises in higher latitudes. As 

 long, now, as the solid crust remains unaffected, the sea in 

 such latitudes must rise, in relation to the land. If the crust 

 lies undisturbed for 1 \ millions of years, the sea in polar regions 

 will rise, relatively to the land, 168 m. It is clear that, in this man- 

 ner, we are able to explain great transgressions by the aid of 

 the hypothesis. A general rise of the sea level in higher lati- 

 tudes, of 100 m. or even more, whilst the solid earth lies undi- 

 sturbed, will inundate large parts of the land and cause great 

 changes in the distribution of land and sea. And the shore- 

 lines in higher latitudes may be brought to recede, either by 

 the rising of the land in the same region or by the subsidence 

 of the sea-bottom in lower latitudes. 



During these transgressions the rising sea, as was shown 

 by Ramsay and v. Richthofen, abraded the coasts, and extensive 



