UNDER WATER. 



6I 7 



mainland separated from their parent continent by an inroad of the sea, as 

 are our islands of Great Britain. 



The sea-bed, however, is very irregular. We find deep and steep 

 valleys, and high hills, but the picturesque peaks caused by the action of air, 

 frost, and water on earth are not, of course, represented under water. 

 Between the Irish coast and Newfoundland we are told the bed is level for 

 nearly four hundred miles. There is a deep declivity before we reach 

 this plain. The centre of the Atlantic is a plain, and on it the most volcanic 

 islands rise, such as Ascension and the Azores. Between England and 

 Greenland there was at one time a land communication, as we have remarked 

 under GEOLOGY, and there are submarine terraces now. [An immense river 

 once ran through Western Europe somewhere about where our islands are.] 



Under the Atlantic we have remains of foraminifera and other tiny 

 animals, with red clay and volcanic remains which must have been of 



submarine origin. The Pacific shows us tops of mountains as islands 

 (Hawaii Isles), and an enormous range must be hidden beneath the waters. 

 What a change in the physical geography of the earth a slight sinking of 

 the water of the ocean would make ; England and the Continent would be 

 united, and many sea-mountains (islands) discovered. The greatest ocean 

 depth is four miles and a half, but in many places a few hundred feet less 

 depth than at present would reveal many changes in the land. 



Every year since the world has gained its present form the streams 

 and rivers have been pouring water, and carrying mud, stones, and gravel 

 ceaselessly into the ocean. In addition to this, the surface water washes 

 the stones away, animals (corals) build up islands from the depths, and take 

 up space in the ocean. We know that if we put our hand in a basin full of 

 water we displace a quantity of the fluid ; so we might imagine that, the 

 sea being already full, every island formed would tend to an overflow 



