MATTHEW, SUPPLEMENTARY NOTE H 



SUPPLEMENTARY NOTE ' 

 By W. D. Matthew 



Before rejDlj'iug to Dr. Barbour's criticism I will say that it is of the 

 sort that is peculiarly welcome, not merely because of its courteous and 

 considerate tone, but because of the author's wide field experience and 

 knowledge of the practical conditions and circumstances of environment 

 that govern the probabilities of any theories of distribution. However we 

 may differ in our interpretation of the evidence, we agree in emphasizing 

 these factors, in the impossibility of solving such j^roblems by the study 

 of any one group of animals, and especially in the need for securing more 

 complete distributional data, towards obtaining which he has devoted so 

 much time and energy. 



Many a false theory gets crystallized by time and absorbed into the 

 body of scientific doctrine through lack of adequate criticism when it is 

 formulated. I should be very sorry to see that happen to the views that 

 I have maintained and hope that adequate and competent criticism will 

 serve to sift out truth from error before they are either adopted or dis- 

 carded. 



Concerning the question of isostatic adjustment I do not think it neces- 

 sary to make any especial comments. I stated in the outset that I was 

 applying the geological views set forth by Chamberlin and others. The 

 evidence that Barbour cites was known to me and is covered by the quali- 

 fying phrases that I used; but the general discussion of the permanence 

 of ocean basins I shall continue to avoid. 



Dr. Barbour devotes considerable space to a criticism of my attempt at 

 a statistical presentation of the possibilities of ^^rafting." He is indeed 

 far less critical of its assumptions than I am. I tried to make it clear 

 that its sole purpose was to show that the hypothesis involved not "mira- 

 cles of transportation" or infinitesimal chances but reasonably probable 

 chances. The quite inexcusable error in my figures to which he calls at- 

 tention is not really material, nor is his conclusion that the calculation 

 shows too many mammals for the known or inferential instances (I do 

 not see that it does, by the way ; but as the point is immaterial will pass- 

 it by). The main reason for introducing a calculation based upon a 

 series of highly inexact approximations was to determine whether this 

 method of transportation would afford a reasonably probable alternative 

 to continental connection, in accounting for the presence of mammals on 



5 Manuscript received by the Editor 12 November. 1915. 



