142 AGE AND AKEA FROM A [pt. ii 



species; Liriodendron tulipifera, Nyssa sylvatica, Pilea pwnila, 

 Dulichium spathaceum were once all inhabitants of Western 

 Europe ; now they are confined to the North American continent. 

 The list could be continued to great length but this is enough to 

 show that genera and species formerly widespread have con- 

 tracted their range and become endemic. Are Ave then to throw 

 over the conclusions of Age and Area which show that immensely 

 the greater proportion of endemics represent new life; and take 

 the position that the two lines of research are mutually contra- 

 dictory? It is not necessary if we make due allowance for the 

 differences of method and subject-matter in the two studies, and 

 their consequent limitations. 



Throughout his work Dr Willis has insisted that his conclusions 

 are based upon mass-investigation, averages. Consequently he 

 warns us that, as with all average calculations, though the con- 

 clusions will be true for the mass they quite possibly may not 

 be true for the individual. Now the whole of palaeobotanical 

 research is based upon the study of the individual; consequently 

 we must be prepared to find that our results may not conform 

 to the conclusions of mass-iuA'cstigation, though we ought to be 

 able to explain the causes of divergence. The palaeobotanist 

 states that some endemics are relicts. Dr Willis replies that if it 

 is so, they are of no account in comparison with the vastly 

 greater number of endemics which are not. Not having counted 

 up the total of endemics in the living flora of the world, as he 

 has done, I am prepared to accept his estimate that relict en- 

 demics form only about 1 per cent, of the total. Even if the 

 percentage were higher, it would not vitiate Dr Willis' reasoning. 

 And here we come to the explanation of our difference. Whereas 

 Age and Area fixes its attention upon, and argues from, the 

 99 per cent., palaeobotan}^ has its attention fixed upon, and 

 seeks to argue from, the 1 per cent. In the nature of things the 

 99 per cent, are outside the scope of its investigations, for if 

 they represent the newest forms of life, then they cannot occur 

 fossil. Consequently, though palaeobotany is right to hold to 

 its 1 per cent., it must yield place in the argument to the superior 

 force of numbers. 



Specific Extermination; Extinction and Survival of 

 Species ; Killing out and Dying out. Specific extermination, 

 the replacement of old forms by new, is continually met with in 

 Tertiary botany; one of the most striking instances is seen in 



