86 B. K. EMERSON TETRAHEDRAL EARTH: INTERCONTINENTAL SEAS 



Van Hise suggests that the effect of the loss of these two great amounts 

 of surface would be mainly concentrated in equatorial regions, and is 

 available to explain the great deformations of the older rocks, especially 

 those of the Archean and Algonkian.* 



In our ignorance of the real amount and the rate of decrease of this 

 large oblateness and the rate of lagging of its plastic adjustment to dimin- 

 ished rotation, we may assume that some small but sufficient part of this 

 equatorial protuberance may have continued later than the Algonkian 

 and furnished the slope required, in this explanation, at least for the 

 earlier chains formed along this line,t and later chains tend strongly to 

 be superimposed on earlier ones. 



Later it may have been reenforced by elevation due to contraction — 

 that is, to tetrahedral deformation. 



General explanation of the formation of the intercontinental zone. — "While 

 the equatorial ring by long tidal ages of friction was being reduced to 

 near its present dimensions (and both Spencer and Darwin, $ in oppo- 

 sition to Lord Kelvin, admit a rapid plastic adjustment of the oblateness 

 to the diminishing rotation), the northern tetrahedral land masses, in- 

 creased by constant cooling, might come into relative prominence, and 

 solar attraction acting upon them might slowly bring the rotation axis 

 into its present position of equilibrium and coincidence with the tetrahe- 

 dral axis, keeping the attractions in the northern and southern hemi- 

 spheres equal. This might ultimately aid, as Green has shown, in causing 

 the axis to incline 23 £ degrees to the ecliptic and to move into its present 

 position. During this change came the marvelous time, ending in late 

 Miocene and even Pliocene, when the great mountain chains rose along 

 this zone, obliterated the nummulitic sea, created the great chains from 

 the Pyrenees to the Himalayas and onto the north of Australia; when part 

 of the plateau of Arabia and western Persia rose and limited the Indian 

 ocean on the south ; when the Central American chains and the Antilles 

 arose and separated the Atlantic and the Pacific, and when perhaps a 

 continental mass sank in the south Pacific coral region. Coincidentl}' 

 Andes and Cordillera and the festoon of curved chains that adorns Asia 

 surrounded the Pacific with a wall of mountains and a line of fire. It 

 is a pleasant suggestion of Sacco § that the human race may have orig- 

 inated about this time in the East Indies, and a French savant, M Ma- 

 nauvrier, has suggested that Pithecanthropus erectus may have obtained 



* Jour. Geol., vol. vi, p. 5G. 



f In the zone of Mont Blanc and in the Carinthian Alps, Variscan post-Carboniferous folds appear 

 beneath the Alpine Tertiary folds. (Suess. See appendix to this paper, p. 100.) 

 fThe Tides, p. 301. 

 g Essai sur l'orog6nie de la terre. Turin, 1895, p. 47. 



