I 



A NATURALIST'S CONTRIBUTION 

 TO THE DISCUSSION UPON 



THE AGE OF THE EARTH 



The Presidential Address read to the Zoological Section of the British 

 Association, September 17, 1896. Reprinted from the Report of the 

 Meeting of the Association held at Liverpool, 1896, p. 808. 



Revised; additional footnotes and terminal note. 



A very brief study of the proceedings of this Section 

 in bygone years will show that Presidents have exercised 

 a wide choice in the selection of subjects. At the last 

 Meeting of the Association in this City in 1870 the 

 Biological Section had as its President the late Professor 

 George Rolleston, a man whose remarkable personality 

 made a deep impression upon all who came under his 

 influence, as I have the strongest reason for remember- 

 ing, inasmuch as he was my first teacher in zoology, and 

 I attended his lectures when but little over seventeen. 

 His address was most characteristic, glancing over a great 

 variety of subjects, literary as well as scientific, and 

 abounding in quotations from several languages, living 

 and dead. A very different style of address was that 

 delivered by the distinguished zoologist who presided 

 over the Meeting. Professor Huxley took as his subject 

 The History of the Rise and Progress of a Single Bio- 

 logical Doctrine, 



Of these two types I selected the latter as my example, 

 and especially desired to attempt the discussion, however 

 inadequate, of some difficulty which confronts the zoolo- 

 gist at the very outset, when he begins to reason from 

 the facts around him, a difficulty which is equally obvious 

 and of equal moment to the highly trained investigator and 

 the man who is keenly interested in the results obtained 

 by others, but cannot himself lay claim to the position and 



