200 F. B. TAYLOR ORIGIN OF THE EARTH's PLAN 



the crustal sheet of Eurasia all that part of Alaska which lies west of this 

 meridian. 



Thus Eurasia, considered as a crustal unit in the Tertiary movements, 

 includes all of Europe with the Atlas ranges and Canary Islands of 

 northwestern Africa; all of Asia excepting the peninsulas of Arabia and 

 India, and in addition all that part of North America which lies west of 

 the mountain angle of Alaska. It seems certain that all this vast crustal 

 sheet was affected by a horizontal creeping movement in the Tertiary age, 

 that it all moved in a southerly direction substantially as a unit, and that 

 the entire belt of Tertiary fold-mountains which forms its southern 

 periphery was made at that time and by that movement. 



FRONTAL OCEANIC DEEPS 



The deepest parts of the ocean are found mostly in long, narrow 

 troughs closely parallel to the continental borders, especially that of 

 eastern Asia.^ The position and relation of these deeps are truly re- 

 markable. The Tuscarora deep, with a depth of more than 5 miles, is 

 the deepest abyss now known. It lies in front of the Kurile Island arc 

 and the arc of north Japan (see figure 2). An even more remarkable 

 deep is that which lies close along the entire front of the great curved 

 arc of the Aleutian Islands and includes the Supan and Maury deeps. 

 This trough is partly shown in figure 2. The principal frontal deeps are 

 shown in figure 7. 



Other deeps in the same relation, but smaller, occur along the east side 

 of a submerged escarpment running north from New Zealand. These 

 lie in the northwest part of the more extensive Aldrich deep. There are 

 deeps along the west coast of South America, such as the Bartholomew, 

 Eichards, and others. Deeps with circular or irregular outlines occur in 

 other relations not so clearly dependent upon adjacent land-masses. Such 

 are the deeps of the Atlantic and the line of deeps running north from 

 the Aldrich deep through the middle of the Pacific. The Challenger deep 

 is near the Junction of the Ladrone and western Caroline Island chains, 

 while the Wharton deep lies partly between Australia and the Malay arc. 

 Deep holes, like the Bartlett and Weber deeps, are characteristic of all 

 the Mediterranean seas. 



The Tuscarora deep and that in front of the Aleutian arc seem clearly 

 linked causally with the continental border and the great mountain ranges 



s See Sir .Tohn Murray's "Bathymetrical chart of the oceans." Scottish Geographic 

 Magazine, vol. xv, no. 10, October, 1899 ; opposite p. 560. Reproduced in Chamberlin 

 and SaUsbury's Geology, vol. i, p. 10. The portion covering the Atlantic Ocean is repro- 

 duced as plate 4, facing page 217. 



