146 Mr Conybeare on the former Temperature 



system of Oxford logic in which I have unfortunately been 

 trained, renders nie less sensible to all the merit of such modes 

 of ratiocination. At present I fear I must rest contentedly in 

 my old belief, that nature has limited, by the laws of climate, 

 not only species, but genera ; not only genera, but families in 

 the organic kingdoms ; that, in many instances, this limitation is 

 absolute ; and that, in many more, genera and families require 

 particular circumstances of temperature for their full and vigo- 

 rous deveiopement ; so that although some stray species may be 

 found beyond the general limits, yet these are rare, and always 

 attest, by their dwarf size, how uncongenial is their habitation. 



If, therefore, I find fossil remains attesting the former exist- 

 ence of genera and families actually thus limited in geographical 

 seats, where none of the races are now found, although they 

 must formerly have flourished there in all the rich variety of the 

 most luxuriant deveiopement, I shall persist in believing it pro- 

 bable that the circumstances which I know to be necessary to 

 the actual existence of the congenerous tribes were originally 

 present in these localities, and that a change of circumstances in 

 this respect, affords the most plausible solution of the problem 

 presented by the local extinction of so many classes of organic 

 l>eings in districts where they once so much abounded. 



To proceed from generals to particulars, the surest test of 

 truth, I will not now dwell on the evidence afforded by the or- 

 ganic remains of the vegetable kingdom, because the admirable 

 exposition of that evidence by M. Brongniart appears in the same 

 number of your Journal with Dr Fleming's memoir ; and I gladly 

 notice the expression of the entire accordance of vour own views 



Neither can I refrain from adverting to the observation, tliat, altbough we 

 may agree witli Cuvier in sujijiosing, that the mastodon liad a proboscis like 

 the elephant, from the general resemblance in structure of the two animals, 

 yet that this conjecture is onlv a probability, and not a renia'-kably strong 

 one, — because the giraffe can provide food from the ground without a pro- 

 boscis, and because the hippopotamus can swim. The last quoted observation 

 I leave witlioiit comment ; but the former is one of the most extraordinary 

 I have met with iu the writings of any naturalist. The provision of a tnink 

 to the elephant is, on account of the shortness of the neck, requisite to enable 

 it to reach the ground, as well as the branches of trees. 'I'he length of the 

 giraffe's neck gives it the means of reaching the ground, as well as branches of 

 trees, without sucli an appendage. I abstain from farther remarks upon this 

 extraordinary ])assage in Dr Fleming's jiaper. 



