134 THE METHOD OF DARWIN. 



The minor instances will be given first, and 

 will be followed by the more general ones. 

 Then will follow deductions which he made, 

 but which are still unverified, or have been 

 verified by others; and lastly will be given 

 some of the instances in which he went clearly 

 wrong in his deductions. 



The instance about to be given may well be 

 placed first, for the purpose of raising a mooted 

 question in logic. Mill took the position that 

 typically the process of inference consists in 

 reasoning directly from one particular case to 

 another; whereas the older and more generally 

 accepted view is that inference must pass by 

 induction from particulars to a general law, and 

 then by deduction from the general law to other 

 particulars. Darwin had found silicified wood 

 in certain tufaceous formations in Patagonia 

 and on the island of Chiloe on the west coast 

 of South America. He afterwards crossed the 

 Andean Cordillera in an east and west direc- 

 tion, and again found tufaceous formations. 

 In his description of the geological section of 

 the Uspallata range he said: "Many of these 

 tufaceous beds resemble, with the exception of 

 being more indurated, the upper beds of the 

 great Patagonian Tertiary formation, especially 

 those variously colored layers high up the river 



