22 On the Distribution of European Birds. [.Jan. 



worthy of attention. Cuvier from an examination of the internal ske- 

 leton of birds, declared that it was, in many instances, impossible 

 to tell the genus, far less than the species. Let us therefore receive 

 with caution such observations, even although they have been consi- 

 dered as plausible by several of the leading geologists. 1 We examined 

 the casts of those so called foot-marks, in the collection of the Royal 

 College of Surgeons of London, 2 but were not at all convinced of 

 their ornithological origin, and till we have further evidence than 

 such impressions, we would be inclined to argue the contrary; for 

 we are as much, or rather more, entitled to infer that they are only 

 vegetable impressions. 3 To find the remains of birds in such a for- 

 mation as the new red sandstone would invalidate one of the grand 

 principles of geology. 



In tracing out the geographic distribution of the animal and ve- 

 getable kingdoms, various methods have been adopted. Some authors, 

 as Humboldt and Latreille, have attempted to trace them according 

 to parallels of longitude and latitude ; others, as Illiger, 4 Fischer, 5 

 &c, according to the various Continents — which no doubt is the most 

 unobjectionable method ; for we find, that when the former is properly 

 examined, it will not stand the test of minute examination, seeing 

 that we have in each of the individual Continents great groups entire- 

 ly confined, and which have no representatives in any other of the 

 other Continents under similar degrees of longitude and latitude, as 

 we ought to find, if the views of Humboldt, &c. were correct. 



Till the laws which regulate the distribution of both the organic 

 and inorganic kingdoms are explained, such a method can never be 

 adopted. We no doubt find secondary causes, such as light, heat, 

 moisture, greater or less distribution of water, configuration of the 

 land, exercising a powerful influence, which is particularly marked 

 out in certain quarters of the globe ; and from authors looking to these 

 individual places alone, they have put more stress upon these causes 

 than what we are entitled to do. Thus, for example, in Northern 

 India, where we find the climate in some places to resemble so much 

 the European, we have a large series of quadrupeds, birds, insects, 

 plants, &c. either identical with the European, Or undergoing such 

 slight modifications, as to entitle them to be considered as mere local 

 varieties, or at least the representatives of the European species. 6 



1 Buckland's Bridgewater Treatise. 



2 For liberty to examine these we were indebted to Mr. Owen. 



3 Our reasons for coming to such a conclusion we shall afterwards give. 



4 Abh. d. Akad. d. Wiss. Zu. Berlin. 1806, p. 236 et 1812 a. 13, p. 221. 



5 Synopsis Animalium et Conspect. Distribut. Geographic. 



6 Vigors, Zool. Proc. Pt. i. pp. 7, 22, &c. Gould's Cent, of Birds. Wils. Cab. 

 Lib. India, vol. iii. p. 78. Jameson, Wern. Trans, in Ed. New Phil. Jour. 



