SIR JOHN MURRAY 177 



whales' ear-bones in numbers which seem 

 incredible. The terrigenous deposits naturally 

 occur most abundantly in the neighbourhood of 

 the land which has produced them, for instance 

 coral mud occurs only near coral islands. Both 

 seals and penguins have been known to drop into 

 the ocean fragments of rock very far away from 

 the land where they originally picked them up. 

 Sir John Murray classified marine deposits into : 



1. RED-CLAY. This, the most widely dis- 

 tributed of all deep-sea deposits, covers a very 

 large portion of the deeper part of the ocean, 

 especially in the Pacific. In Red Clay there 

 were few if any remains of calcareous skeletons, 

 but flinty spicules from the siliceous organisms 

 such as sponge-spicules and Radiolarian skele- 

 tons may be detected. Sir John estimated that 

 the Red Clay covers an area of about 51,500,000 

 square miles of the bottom of the sea. 



2. RADIOLARIAN-OOZE. Then we have the Radi- 

 olarian-ooze, consisting of the flinty skeletons 

 of unicellular animal organisms, which is char- 

 acteristic of the deep tropical waters in the Pacific 

 and Indian Oceans. He estimated that the 

 Radiolarian-ooze covers 2,290,000 square miles 

 of the ocean's depths. 



M 



