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CHAP. IX. 



THE COASTS OF SAINTONGE. 

 LA ROCHELLE. 



Journey from Paris to La Rochelle. Historical notice of that town: 

 its origin ; its constitution ; its sieges. Decay of La Rochelle. 

 Poverty of the coast ; reciprocal dependence of the kingdoms of 

 nature. The Branchellion ; its external characters ; its lym- 

 phatic respiration. The natural method ; insufficiency of the 

 principle of dominant characters in the study of the lower animals. 



A MERE glance at the geological atlas of France 

 will suffice to show that our western coasts present 

 two totally different varieties of geological structure. 

 At the extremity of Normandy, along the whole 

 length of Brittany, and on a considerable part of 

 Poitou, the ocean strikes upon a coast line consisting 

 of schistous or granitic rock ; while from Talmont as 

 far north as Saint Vaast nothing is to be seen but 

 limestone, which finally merges in sand and alluvial 

 deposits. The pursuit of marine animals had first 

 led me to the shores of the central mass of our con- 

 tinent ; subsequently I explored those of the Basque 

 country and the Channel. In all these different 

 regions, the animal populations, or, to use the current 

 expression, the/awrcos, appear to me to present cha- 

 racteristic differences corresponding to the nature of 

 the geological strata. I felt that to confirm this 

 general fact it would be necessary for me to visit 



