196 



THE OCEAN. 



ocean are either built by zoophytes, or else cast up by volcanos from the 

 bottom of the sea ; one or the other is, without exception, the origin 



Fig. 8G.— Celebes and Gilolo. 



of all these islands. The first, as we know,* are disposed in atolls, or 

 annular reefs, formed themselves of rings of smaller dimensions, while 

 cones of lava, that are elevated in the open sea, rise proudly above 

 the waves, and reveal the independence of their origin by a declivity 

 which is continued pretty regularly below the waters. Still we can 

 see by the example of the volcano of Stromboli, and more plainly 



t. -c 



TTrrss"-— — ^^-^---=r--s:?=-r?5 



Pig. 87.— Section of Stromboli, from S.W. to N.E. 



* See in Vol. I. the section entitled, The Slow Oscillations of t/ie Terrestrial Soil; and be- 

 low that entitled, TA^ IJarth and its Fauna. 



