THE COASTS OF SAINTONGE. 271 



themselves securely to these surfaces, which are 

 always being broken up, and on this account they 

 are of much rarer occurrence. With their disap- 

 pearance, numerous species of animals vanish from 

 sight which either feed upon these marine plants, or 

 find a retreat within their branches. The same con- 

 ditions oppose similar obstacles to the multiplication 

 of Zoophytes and other fixed animals. With the 

 herbivorous species and with those which are sta- 

 tionary in the manner of plants, all the carnivorous 

 species also disappear which live at their expense. 

 If, moreover, the limestone happens to be formed of 

 fissured strata, which the waves can easily break up, 

 the preceding causes exercise a still stronger action, 

 while, moreover, those animals which usually conceal 

 themselves or at any rate deposit their eggs within 

 the recesses of the rock, diminish in their turn from 

 the want of safe retreats. Finally, if these strata 

 form inclined planes towards the sea, the springs in 

 the neighbouring district follow these water-courses, 

 and bursting forth in streams along the beach, di- 

 minish the saltness of the water which washes the 

 shore and drive away all those animals which are 

 more decidedly marine in their character. 



It is obvious, therefore, that the richness and cha- 

 racter of the littoral fauna depend upon the minera- 

 logical composition and geological structure of the 

 district. This is one of the thousand examples which 

 show us how great an influence the mineral king- 

 dom occasionally exerts over the two other kingdoms 

 of nature, and how organised and living beings may 

 be placed in a state of dependence on inert bodies, 



