IV DEPTHS AND DEPOSITS OF THE OCEAN 141 



by the U.S.S. " Tuscarora" in 1874. A considerable portion of 

 this deep is covered by depths exceeding 4000 fathoms, includ- 

 ing one large elongate area founded on eight soundings, and 

 two small areas founded each on single soundings — one towards 

 the southern end of the deep and the other in the extreme 

 north. 



Wha7'ton Deep lies in the eastern Indian Ocean, extending wharton 

 from lat, 10 S. to the Tropic of Capricorn, and is estimated to ^^'^' 

 cover an area of 883,000 square miles ; it includes the two 

 deepest soundings yet recorded in the Indian Ocean, viz. 3828 

 and 3703 fathoms, taken in 1906 by the German ship " Planet" 

 in what is called by the Germans the " Sunda Graben " at no 

 great distance from the coast of Java. 



Nares Deep is the largest deep lying wholly in the Atlantic Nares Deep. 

 Ocean, and at the same time the deepest. Its outline is most 

 irregular, extending from lat. 18° N. to 34° N., and in the 

 neighbourhood of the West Indies the floor of the deep sinks 

 to depths exceeding 4000 fathoms over a limited area, the 

 maximum depth being 4662 fathoms, recorded by the U.S.S. 

 "Dolphin" in 1902. This deep is estimated to cover an area 

 of 697,000 square miles. 



Aldrich Deep lies in the Central South Pacific, extending Aidrich Deep, 

 from lat. 15° to 47° S., and is estimated to cover an area of 

 about 613,000 square miles. It includes seven small areas 

 lying along its western border in which the depth exceeds 4000 

 fathoms. In three of these the depth exceeds 5000 fathoms, 

 viz. 5022, 5147, and 5155 fathoms, recorded by Commander 

 Balfour on board H.M.S. "Penguin" in 1895. Numerous 

 soundings have been taken round these* seven deepest areas, 

 and seem to prove that they are all separated from one another 

 by ridges covered by water between 3000 and 3700 fathoms in 

 depth. The outline of this deep is remarkable, and it is 

 possible that future soundings will show it to be two distinct 

 deeps, for a rise, on which soundings in 2000 to 2900 fathoms 

 have been recorded, interrupts the sequence of great depths. 



Swire Deep lies in the North-West Pacific in close proximity SwireDeep. 

 to the Philippines, and extends from about lat. 4° N. to 

 lat. 25' N., covering an area of about 550,000 square miles. It 

 is broken up by several rises on the ocean-floor where depths 

 of 2700, 2800, and 2900 fathoms have been recorded ; on the 

 other hand, at remarkably short distances from the coasts of 

 Mindanao and Samar Islands in the Philippines are two areas 

 with depths exceeding 4000 fathoms, a similar depth being 



