232 THE OCEAN 



cetaceans. All these organic remains will be 

 deeply impregnated with the peroxide of 

 manganese, and some of the earbones and 

 sharks' teeth will be surrounded by concentric 

 layers of black manganese nearly an inch in 

 thickness. Some of the teeth and earbones 

 belong to extinct species. Besides these 

 there will be hundreds of other manganese 

 nodules formed around palagonitic and other 

 volcanic fragments. These will all be embed- 

 ded in a dark brown clay, consisting of 

 hydrated silicate of alumina and oxides of 

 iron and manganese, and this clay will con- 

 tain crystals of phillipsite in the form of 

 balls, aggregates varying in number, twins, 

 or single individuals. Lastly a magnet will 

 draw from the clay a good number of magnetic 

 spherules, believed to be of cosmic origin. 

 Some have a black coating which covers a 

 metallic nucleus of iron and nickel. Others, 

 brown in colour and crystalline in structure, 

 are called " chondres," and have hitherto only 

 been found in meteorites. 



This is a very remarkable assemblage of 

 organic and inorganic materials. How is 

 their presence at this spot and depth to be 

 explained ? The depth is too great for more 

 than a few of the calcareous surface shells to 

 reach the bottom, and there are very few 

 remains of siliceous organisms in the deposit. 



