70 B. K. EMERSON — TETRAHEDRAL EARTH: INTERCONTINENTAL SEAS 



The second or Silurian map (plate 10, b) is too hypothetical to have 

 great value in this connection. 



In the third map (plate 10, c) the broad Carboniferous land belts the 

 earth in the northern hemisphere, and Gondwana land connects the 

 southern continents, and plate 11, d shows a similar state of things in the 

 Trias. These lands are carried in broad bands across the present oceans 

 largel}' on the evidence of faunal identity or similarity, and the lines 

 could generally be carried in northward and southward loops across the 

 present oceans, as is done in several cases. 



" There is not wanting evidence," says Seward,* " in favor of the 

 Glossopteris flora having been first differentiated in an Antarctic conti- 

 nent toward the close of the Carboniferous period." 



The last investigations of M Zeiler in South America show that the 

 Glossopteris flora came from the south, and the same indications ap- 

 pear in its other occurrences. f 



" I have sometimes speculated," says Darwin, " whether there did not 

 exist somewhere during long ages an extremely isolated continent, per- 

 haps near the south pole. "J 



The Jurassic map usually quoted is the map of Neumayr, and it is 

 interesting to compare therewith the much later map (plate 11, a) of the 

 same period, just published by de Lapparent, who bases his work 

 avowedly on that of Neumayr. The approximation to the tetrahedral 

 sjinmetry is much greater than in the older map. 



In Jurassic time there is a distinct approach to the form demanded 

 by the hypothesis ; in the Cretaceous (plate 11, 6, c) it is much increased, 

 although the map-makers take great, and it maybe unwarranted, liber- 

 ties with the north Atlantic. 



In the Eocene (plate 11, d) the assumptions of the hypothesis are best 

 met, in one respect better than in the modern map, since the Indian 

 ocean is continued north between India and Africa and east of the Urals 

 to the Arctic, and the Atlantic contracts west of Scandinavia. The 

 Mediterranean water belt still continued, but the Miocene mountain- 

 making, extending from Pyrenees to the Himalayas, raised parts of 

 Arabia and Persia and cut off the northern prolongation of the Indian 

 ocean. There is a certain survival of the continental nuclei and pro- 

 gressive evolution of the oceans. 



I call attention again to the reproduction of Green's maps, showing, to 

 diminish distortion, the four quarters of the earth instead of the usual 

 hemispheres, and have drawn in the outlines of the ideal continents 



* Association of Sequoia and Glossopteris in South Africa. Quar. Jour Geol. Soc, vol. 5:5, j>. 327. 



7 Bertrand : Bull. Geol. Soc, France, vol. xxiv, 1S9C, p. 24. 



| Darwin : Life and Letters. ... 



