Zoological Characters in Geologt/. 251 



la Here, Honfleur, and Dives, &c. and in England at Tets- 

 worth, &c. We might increase the number of analogies by 

 comparing the lenticular rock, penetrated by oxide of iron, 

 which de Saussure describes as a true iron ore, to the iron 

 sand (sable ferrugineux), which often occurs in beds of 

 greater or less thickness beneath the green sand. 



Thus, notwithstanding the very considerable distance of 

 the places ; notwithstanding the different form of the moun- 

 tains and rocks ; notwithstanding a few mineralogical dif- 

 ferences, the yellowish calcareo-ferruginous rock mixed with 

 greenish grains of the Perte du Rhone, presents, it may be 

 said, a complete analogy to the green sand of the north of 

 France and the S.E. of England, for the characters of the 

 associated rocks, minerals, and superposition, agree with 

 those afforded by the organic remains in establishing this 

 analogy of formation. 



§ VI. Formation of the chalk epoch in the Buet chain, 

 and a comparison of this rock with that of the transition 

 class in the Montagne des Fis. 



We are now arrived at an approximation that appears 

 much more extraordinary — one that I should still ofFer with 

 hesitation (for my mode of considering this subject dates as 

 far back as my Swiss tour in 1817), if my opinion had not 

 been confirmed by that of Mr. Buckland, an opinion which 

 that geologist entertained when he passed through Paris in 

 the end of 1820, and which he has published in the Annals 

 of Philosophy, for June, 1821. 



A chain of elevations extends from the summit of the 

 Buet (in the Savoy Alps) which apparently constitute a 

 dependence on it, and which are remarkable for their black 

 colour, for their form, which is often precipitous on one side, 

 with a more or less rapid slope on the other, for their very 

 considerable elevation above the level of the sea, an ele- 

 vation which amounts to 2500 metres [8200 feet]. 



