84 Professor Owen on hriti»h Fo.uit Vepttles. 



Not a single species of fossil reptile now lives on the pre- 

 sent surface of the globe. 



The characters of modern genera cannot be applied to any 

 Species of fossil reptile in strata lower than the tertiary for- 

 mations. 



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 Ichthyo- 

 saurus 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 

 ftny 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 different species of reptiles were suddenly introduced 

 \ipon the earth's surface, although it demonstrates a certain 

 systematic regularity in the order of their appearance. Upon 

 the whole, they make a progressive approach to the organiza- 

 tion of the existing species, yet not by an uninterrupted suc- 

 cession of approximating steps. Neither is the progression one 

 of ascent, for the reptiles have not begun by the perenni- 

 branchiate type of organization, by which, at the present day, 

 they most closely approach fishes ; nor have they terminated 

 at the opposite extreme, viz. at the Dinosaurian order, where 

 we know that the reptilian 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 reptiles, were originally impressed upon them at 

 their creation, and have been neither derived from improve- 

 ment of a lower, nor lost by progressive development into a 

 higher type. 



The general progressive approximation of the animal king- 

 dom to its present condition has been, doubtless, accompanied 

 by a corresponding progress of the inorganic world j and thus. 



