202 REPORT— 1841. 



saurus, Goniopholis, &c., of the Oolitic and Wealden strata, corresponds 

 with the prevalence of the well-mailed Ganoid order of fishes in the same 

 formations. 



The fossil reptiles, like the fossil fishes, approximate nearest to existing 

 species in the tertiary deposits, and diiFer from them most widely in strata 

 whose antiquity is highest. 



Not a single species of fossil reptile now lives on the present surface of 

 the globe. 



The characters of modern genera cannot be applied to any species of fossil 

 reptile in strata lower than the tertiary formations. 



No reptile, with vertebrae articulated like those of existing species, has 

 been discovered below the chalk. 



Some doubt may be entertained as to whether the Ichthyosaurus communis 

 did not leave its remains in both oolitic and cretaceous formations, but with 

 this exception no single species of fossil reptile has yet been found that is 

 common to any two great geological formations. 



The evidence acquired by the researches which are detailed in the body 

 of this Report, permits of no other conclusion than that the diff'erent species 

 of Reptiles were suddenly introduced upon the earth's surface, although it 

 demonstrates a certain systematic regularity in the order of their appearance. 

 Upon the whole thej' make a progressive approach to the organization of the 

 existing species, yet not by an uninterrupted succession of approximating 

 steps. Neither is the progression one of ascent, for the Reptiles have not 

 begun by the perennibranchiate type of organization, by which, at the present 

 day, they most closely approach fishes ; nor have they terminated at the op- 

 posite extreme, viz. at the Dinosaurian order, where we know that the Rep- 

 tilian type of structure made the nearest approach to Mammals. 



Thus, though a general progression may be discerned, the interruptions 

 and faults, to use a geological phrase, negative the notion that the progression 

 has been the result of self-developing energies adequate to a transmutation 

 of specific characters ; but, on the contrary, support the conclusion that the 

 modifications of osteological structure which characterize the extinct Rep- 

 tiles, were originally impressed upon them at their creation, and have been 

 neither derived from improvement of a lower, nor lost by progi'essive develop- 

 ment into a higher type. 



The general progressive approximation of the animal kingdom to its pre- 

 sent condition has been, doubtless, accompanied by a corresponding progress 

 of the inorganic world ; and thus, the diff'erences which comparative anatomy 

 demonstrates to have existed between the vertebrated inhabitants of the 

 secondary epochs of the geological history of the earth, and the tertiary and 

 present periods, form legitimate grounds for speculation, not only on the 

 essential nature and causes of those diflierences, but upon the progressive 

 changes to which our planet and its atmosphere may have been subject. For 

 whether there had been grounds for regarding the organic phaenomena of pri- 

 maeval times as earlier stages in the progressive development and transmuta- 

 tion of species, or whether, as the closest investigation of these phaenomena 

 seems to demonstrate, they have been the result of expressly created and suc- 

 cessively introduced species, — they naturally lead the physiologist to specu- 

 late on the varying conditions of the surrounding media to which such organic 

 differences may have related. 



Now Reptiles mainly and essentially diflFer from Birds and Mammals in 

 the less active performance of the respiratory function, and in a lower and 

 simpler structure of the lungs and heart, whereby they become, so to say, 



