The Mighty Deep 



side looked upon its own view for the time being 

 as the only right one. But as again with many 

 difficult problems the fairer and wider view 

 recognises the possibility of truth in both ex- 

 planations, and probably in the end both will 

 prove to be in a measure right. 



Many other kinds of rock, as well as sand- 

 stone, have been built under ocean-waters in past 

 ages, constructed of minute particles, piled to- 

 gether, and hardened. Some sorts, like sand- 

 stone, are only or chiefly mineral ; while others 

 are only or chiefly " organic " that is, are mainly 

 composed of the remains of " organised " or living 

 beings. About the latter much has to be said in 

 future chapters. 



A very few words in the close of this chapter, 

 as to the classifying of different kinds of Rocks, 

 may not be amiss. 



Ocean-deposits, or Ocean-buildings, are often 

 roughly divided into three groups. 



In "Deep-Sea Deposits" are included all that 

 lie beyond the Hundred-fathom Line, or a depth 

 of six hundred feet. 



In " Shallow- water Deposits " are included all 

 that lie between six hundred feet deep and low- 

 water mark. 



In " Littoral Deposits " the word coming from 

 132 



