THE AGE OF THE EARTH FROM THE PALEONTOLOGI- 



CAL VIEWPOINT. 



By JOHN M. CLARKE. 

 (Read April 22, IQ22.) 



It falls to me to consider this knotty problem on the basis of the 

 biological evidence alone, in so far as it is possible to disentangle this 

 from its almost inevitable complication with geological accompani- 

 ments. In saying biological I mean, of course, biology with the time 

 element generously admitted ; that is, not the biology of the instant, 

 the present, but the long biological panorama leading up to the 

 present. Thus I am in a different case to some of my colleagues, for 

 I presume it safe to say that life can have come into being only as 

 a secondary potency in the evolution of force. Just what I mean is 

 that the combination or interaction of physical energies of different 

 categories did not produce the form of energy we designate as life 

 till after a very long chapter of the earth's planetary history had been 

 written, I may as well frankly say at the beginning that there can 

 be little hope of arriving either at a reliable or an approximate con- 

 clusion as to the age of the earth through this paleontological channel, 

 unless the study of the chronological development of life may in 

 some way afford a measure of the rate of vital processes and thus the 

 measure of some short span or infinitesimal fraction of earth history. 

 This is a shadowy road and this presentation must resolve itself into 

 consideration of such evidences as there may be for time-requisites 

 in the consummation of evolutionary biological procedures, whether 

 in gross or in detail. The bare statement of this fact in such vague 

 form must carry with it an indication of the grave uncertainty of the 

 results except to minds of the fourth dimension. I am not convinced 

 that it is within the power, now or ever, of even the most refined 

 understanding of paleontology, to accomplish this and establish such 

 standards of measurements. Nor am I at all confident that the 

 attempts which have been made to establish such rates of procedure 



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