EVIDENCES FROM PALAEONTOLOGY 69 



estimates within the bounds of Lord Kelvin's older calculations. Wal- 

 cott, in 1893, on the basis of the stratigraphic record and the known 

 discharge of sediment by rivers, concluded that 70,000,000 years had 

 elapsed since sedimentation began in the Archeozoic. Sir Archibald 

 Giekie places the tune at 100,000,000 years, and most geologists have 

 tried, although with difficulty, to fit the record within these estimates. 



" Since the discovery of radium, all of the calculations previously 

 made have been set aside by the new school of physicists, and now 

 the geologists are told they can have 1,000,000,000 or more years as 



the time since the earth attained its present diameter Even 



if finally it shall turn out that the physicists have to reduce their 

 estimates as to the age of certain minerals and rocks, geologists 

 nevertheless appear to be on safer ground in accepting their estimates 

 than those based either on sedimentation, chemical denudation, or loss 

 of heat by the earth." 



[The last decade has seen the demise of the outworn objection to 

 evolution based on the idea that there has not been time enough for 

 the great changes that are believed by evolutionists to have occurred. 

 Given 100,000,000 or 1,000,000,000 years since life began, we can then 

 allow 1,000,000 years for each important change to arise and establish 

 itself. We can also understand why it is that so little change can be 

 noted in the majority of wild animals and plants within the historic 

 period. A thousand years in the development of the race is like a 

 second hi the development of an individual and, though no one can 

 notice any change in a growing creature in a second or a minute, very 

 radical changes can be noted hi an hour or a day or a year. We cannot 

 see any movement hi an hour hand of a clock, but it moves with 

 certainty around the dial in a relatively short time. There is there- 

 fore no shortage of tune. Evolution may have been infinitely slow, 

 but time has been infinitely long. The accompanying tune scale 

 shows the lapse of time and the distribution in time of the main 

 groups of animals (Fig. i). ED.] 



ON THE PRINCIPAL GENERAL FACTS REVEALED BY A 

 STUDY OF THE FOSSILS 



[i. None of the animals or plants of the past are identical with 

 those of the present. The nearest relationship is between a few species 

 of the past and some living species which have been placed in the same 

 families. 



