4 ON THE LAW WHICH HAS REGULATED 



acquainted, or has been able to observe himself. 

 These have all served to convince him of the correct- 

 ness of his hypothesis. Fully to enter into such a 

 subject would occupy much space, and it is only in 

 consequence of some views having been lately pro- 

 mulgated, he believes, in a wrong direction, that he 

 now ventures to present his ideas to the public, with 

 only such obvious illustrations of the arguments and 

 results as occur to him in a place far removed from 

 all means of reference and exact information. 



A Law deduced from well-known Geographical and 

 Geological Facts. 



The following propositions in Organic Geography 

 and Geology give the main facts on which the 

 hypothesis is founded. 



Geography. 



1. Large groups, such as classes and orders, are 

 generally spread over the whole earth, while smaller 

 ones, such as families and genera, are frequently 

 confined to one portion, often to a very limited dis- 

 trict. 



2. In widely distributed families the genera are 

 often limited in range ; in widely distributed genera, 

 well marked groups of species are peculiar to each 

 geographical district. 



3. When a group is confined to one district, and 

 is rich in species, it is almost invariably the case 

 that the most closely allied species are found in the 

 same locality or in closely adjoining localities, and 



