426 ALEXANDER AGASSIZ 



As this condition, which Agassiz had previously sus- 

 pected, became apparent, he took a greater and greater 

 interest in the work, which was continued with unfail- 

 ing regularity, to develop the extent of the desert. As 

 each successive haul of the trawl was swung; on board 

 he would, after examining its contents of mud and nod- 

 ules, exclaim with a smile, " Not a thing," and while in 

 this region was most pleased when he got least. 



These desert tracts of the ocean's bottom can be ac- 

 counted for by the fact that they exist in regions where 

 there are no great currents to transport life over the 

 upper layers of the sea. As there is little or no life on 

 the surface, no food falls to the bottom, and there is 

 nothing to support life there. In such places for various 

 reasons there is but little accumulation of any deposit, 

 and on this account the teeth of the huge Tertiary 

 sharks, and the ear-bones of the whales, which must 

 once have frequented these waters in large numbers, 

 have not been covered up. Other portions of the skele- 

 tons of these animals are not found because they are 

 more easily dissolved, and have disappeared. 



While in this desert region, it seemed impossible to 

 avoid manganese nodules. Sometimes the trawl would 

 come up so heavily loaded with these concretions, which 

 looked much like irregular potatoes, that as the bag left 

 the water, after a few labored turns of the engine, the 

 net would give way, and only its remnants would be 

 swung on deck. Later in the voyage Mr. Chamberlain 

 contrived a support by which this danger was very much 

 lessened. 



Murray, the authority on such matters, accounts for 

 these nodules somewhat as follows. He considers them 

 secondary formations derived from the decomposition of 



