74 B. K. EMERSON — TETRAHEDKAL EARTH: INTERCONTINENTAL SEAS 



120 degrees apart, and indeed the fourth Antarctic one also, and outlined 

 the development of the North American continent and brought out the 



greater development of the newer formations southward. He was the 

 first to enumerate extensively the coincidences of the earth's feature lines 

 with great circles. 



He suggested that the nucleus of the earth was a tetrahedron or a 

 spherical tetrahedron, and figures in illustration the " nucleiform tetra- 

 hedron " and a " crystal of carbon (diamond) being a curved tetrahe- 

 dron, sometimes almost spherical."* 



Map of Michel-IAvy. — The interesting map of Michel-Levy, cited on 

 page 82, deserves careful study (plate 13). It is constructed strictly in 

 the spirit of Elie de Beaumont. The author starts directly from the as- 

 sumption that the crust will tend to break along the tetrahedral edges 

 and draws as the three edges meeting at the south pole the Carbonif- 

 erous Australian Alps, the Tertiary Andes, and the Erythrian rift valley 

 of Africa and Asia Minor, which is not a mountainous region, but near 

 a watershed. 



We have been guided rather by the idea that the main geological ac- 

 cidents would occur around the borders of the low rising domes, where 

 the shoreline determines sedimentation, mountain-making, and vulcan- 

 ism. By placing the tetrahedral pole at Bering strait, he ignores the 

 symmetry of the Arctic ocean and the Antarctic sea, and the symmet- 

 rical position of the three Archean coigns.f 



But the delightful thing in the whole matter is that he places the tetra- 

 hedral pole in Bering strait and leaves the earth pole where it is, and 

 we in the next chapter shift the earth pole to Bering sea and leave the 

 tetrahedral pole where the earth pole now is. He extends the condi- 

 tions of the western Mediterranean where the southern ranges have 

 moved south, the northern and western north, more widely than Suess 

 has done, and here we have followed Suess. 



Doctor Gregory % follows Michel-Levy closely, but assumes, in addi- 

 tion, that the earth was in pre-Carboniferous times a tetrahedron with 

 apex directed north instead of, as at present, directed south, with Austra- 

 lian, African, and Patagonian Archean nuclei, with the Hercynian and 

 perhaps the Carboniferous chains of Tsinling for the meridional chains, 



* Key to the Geology of the Globe. An essay designed to show that the present geographical, 

 hydrographical, and geological structures observed on the earth's crust were the result of forces 

 acting according to fixed demonstrable laws analogous to those governing the development of 

 organic bodies. 1857, pp. -'■>, 60. 



fSur la coordination et la repartition des fractures et des effondrements de I'ecorce terrestre en 

 relation avec les epanchements volcanique. Bull. Geol. Soc. France, vol, xxvi, 1898, p. 105. 



X Loc. cit. 



