REVIEWS. 



93 



two thus remotely situate being the same, they must have 

 originated from the same geological agency. 



Having devoted the first divisions of the work to a review 

 of the classification of these fossils, and assigning their posi- 

 tion, and subsequently, as we have endeavoured to report in 

 a succinct manner above, their distribution having been con- 

 sidered, M. Roquan proceeds to impart to us his examina- 

 tions with reference to their division and arrangement, which 

 we will add after the insertion of a few remarks. 



M. Roquan states that having collected an immense num- 

 ber of specimens of all forms, ages, and in different degrees 

 of fossilization, he was enabled to observe several important 

 facts. Amongst these, he states that having been impressed 

 in favour of Lamarck's reduction of the total number of spe- 

 cies of Spherulites from the seven recognised by Lapeirouse to 

 three species only, possessing, as he said, distinct forms and 

 characters, he endeavoured to recognize those characters as 

 the means of classifying the species occurring at Rennes ; 

 but after close examination he found that all the specimens 

 he obtained at that locality merged into one general specific 

 character, however apparently different they might have 

 seemed on first sight. Not willing, however, to change an 

 opinion upon these grounds; without closer examination, 

 Mr. Roquan deputed a friend, to examine the species in La- 

 marck's collection, labelled in his own handwriting ; and 

 from an inspection of these he was convinced that his first 

 judgment was right, and that M. Lamarck had been mis- 

 led by the variety of forms and aspects under which the 

 Spherulites occur. He therefore includes those found at Cor- 

 bieres under one denomination only — Spherulites ventricosa. 



Our author states that he followed in the same course 

 with reference to the Hippurites, and states that he recog- 

 nized six species in the strata of Corbieres, entirely distinct 

 and marked under all circumstances. 



