54 MEMOIRS OF 



has yet been found in a fossil state. All their localities have 

 been stated, and all the collections mentioned where they have 

 been preserved, with a laborious fidelity and extraordinary 

 erudition. He had, however, many difficulties to conquer, 

 among which was that of the incredulity of others, who, 

 being ignorant of the laws of organization, of the necessa- 

 ry co-existence of certain forms, did not comprehend how it 

 was possible to re-establish an animal from the fragments of 

 its bones scattered through the layers of the earth. How he 

 triumphed will be gathered from the following extract from a 

 letter written to Dr. Duvernoy, a few days after a meeting in 

 which he had been obliged to discuss some particular objec- 

 tions addressed to him. He thus wrote (1806.) '' They 

 have just brought me the skeleton of an anoplotherium, 

 which is almost entire, taken from Montmartre, and nearly 

 five feet long. All my conjectures have been verified, and 

 I find that the animal had a tail, as long and as large as that 

 of a kangaroo, which completes its singularities." For the 

 furtherance of his inspection of the neighbourhood of Pa- 

 ris, M. Cuvier associated the learned geologist, M. Brong- 

 niart, with him in his researches, who more particularly con- 

 fined himself to fossil mollusca, and comparative observa- 

 tions concerning other countries. The principal geological 

 result of these inspections was to ^make known the fresh 

 water deposits above the chalk, each deposit covered by a 

 marine deposit ; irrefragable proofs of several irruptions 

 and alternate retreats of the sea, in the basin of Paris and 

 its environs, since the period of the chalk formation. This 

 discovery was solely due to M. Cuvier, and it was at Fon- 

 tainebleau that the truth suddenly flashed across his mind. 

 " Brongniart," he cried, " j'ai trouve le noeud de Taffaire." 

 " Et quel est-il ?" asked M. Brongniart. " C'est qu'il y a 

 des terrains marins, et des terrains d'eau douce." replied M. 

 Cuvier.* It is most interesting to see how after many years 

 of uninterrupted and difficult investigation, of profound 

 study and meditation, M. Cuvier, in his beautiful prelimina- 

 ry Discourse, sums up the facts which afford indisputable 

 evidence of these great phenomena. " I think," said the 



* "I have solved the difficulty."" And what is it ?" " It is, that there 

 are fresh watr earths, and earths of salt water formation." 



