(^ . . v. 

 [* AUG 4 ,1916 



THE 



AMERICAN JOURNAL OF SCIENCE 



[FOURTH SERIES.] 



Art. IX. — The Problem of Continental Fracturing and 

 Diastrophism in Oceanica;* by Charles Schuchert. 



Latitudinal arrangement of ancient lands.— Paleogeographic 

 studies during the past thirty years have been developing the 

 hypothesis that the ancient continental platforms were arranged 

 latitudinally rather than longitudinally as they are now, and 

 further, that their areal extent, including their emerged and 

 submerged portions, was greater than at present. It appears 

 that vast landmasses have been fractured, broken up, and more 

 or less permanently taken possession of by the oceans, a history 

 which none exhibits better than the Australia-New Zealand 

 region. 



Time ivhen oceans became deep. — We have learned from the 

 several deep-sea expeditions something of the rare and strange 

 life of the oceanic abysses. . An analysis of these organisms 

 shows that no Paleozoic forms occur among them and, indeed, 

 very little of the life is ancestrally traceable even to the stocks 

 of Triassic times. It is with the Jurassic and later life that 

 the organisms of the abysses have their affinities. This seems 

 to indicate that the oceans have been progressively deepened 

 only since the Triassic. As one of the most marked crustal 

 deformations, however, began in the Coal Measures of the 

 Paleozoic and continued, though with pauses, well into the 

 Triassic, it therefore appears that the oceans have been periodi- 

 cally enlarged and deepened ever since Permian time. This is 

 in keeping with the theory that the earth's radius has been 

 gradually diminishing, and that the periodic compensation 



* Read before the National Academy at Washington, April 17, 1916. 



Am. Jour. Sci.— Fourth Series, Vol. XLII, No. 248. — August, 1916. 



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