find on the Fossil Remains contained in them. 1 3 1 



resemblances and striking diflTereuces are at the same time 

 perceivable. In some instances the generic characters ma- 

 terially differ, bin in most thev very closely correspond; 

 whilst the specific characters are very rarely found to agree, 

 except when the fossil appears to have existed at, compara- 

 tively, a late period. Ot man, who constitutes a genus by 

 himself, not a smgle decided remain has been found in a 

 fossil state. 



Chemical analysis has been called in to the aid of the na- 

 turalist, in order to account for the perfect state of preserva- 

 tion observable in remains organized with the most exqui- 

 site delicacv, and which there is every reason for supposing 

 to have been readily decomposable in their receiit state. 

 From this invcstisration we learn the manner in which these 

 memorials of the old world, so interesting and so frail, have 

 been preserved. Some have been impregnated with cal- 

 careous matter, others with siliceous, and others with iron 

 or copper pyrites. 



But these facts, however important and interesting, can- 

 not, when considered by themselves, add njuch to our 

 knowledge respecting the formation and strr.cture of the 

 earth. To derive any information of consequence from 

 ihem, on these subjects, it is necessary that their examina- 

 tion should be connected with that of the several strata in 

 which they are found *. 



Already have these examinations, thus carried on, taught 

 us the foUowina: hiahlv instructive facts. That exactly si- 

 milar fossils are found in distant parts of the same stratum, 

 not only where it traverses this island, but where it appears 

 again on the opposite coast: that, in strata of considerable 

 comparative depth, fossils are found, which are not dis- 



• This mode of conducting' our inquiries was long since recommended by- 

 Mr. W. Smith, who first noticed that culuin fossils me peruliar ti>, and are 

 onlyfuurid lodged in, particular strata ; and wlio first ascertained the constancy 

 in the order oj' ^uperponti'in, and the contmuity, of the strata if this island. It 

 ■will appear from the following- quotation, that these observations hiive lately 

 also occurred to Messrs. Cuvier and Brongniart, whilst examining into the 

 nature of the strata of the neighbourhood of Paris. " Cette Constance danSs 

 I'ordre de superposition des couches les plus minces, et sur une etendue de 

 12 myriamctres au moins, est, selon nous, un des faits les plus remarquables 

 que nous ayons constates dans la suite de nos reeherches. 11 doit en rdsultet 

 pour les arts ct pour lag^ologiedes consequences d'autaut plus intdressanies 

 qu'elles soiit plus sures. 



" Le moven que nous avons tmployi pour reconnoitre au milieu d'un si 

 grand nomorc de lits calcaircs, un lit deja observe dans un canton trcs dioigne, 

 ett pris dc la nature des fossiles rcnfermi-s dans chaque couche: ccs fossiles 

 •ont toujours geiidralement les mCmes dans les couches correspondantes, ut 



Jresenteut des dilFcrcnccs d'cspcces assez notables d'un systeme des couchei 

 un autre tysttme. C'ckt un signe de rtconnoissance qui jusqu'a present 

 ae nous a pu* tromp^." — Am-aUi da Mniium d^liiit, ^'at. tome xi. p. 307. 



I 2 covered 



