70 



hard facts which told a tale of paramount importance and exciting 

 interest, revealing in each formation of the Earth's crust pages of unwrit- 

 ten history : it was the Earth telhng its own tale. 



Sir Archibald Geikie then pointed out the salient conclusions 

 which had been already arrived at, with reference to the boundless anti- 

 quity of the gobe, presented Lord Kelvin's views as to the limit of 

 time that may be assigned to our planet's antiquity. " He estimated 

 that the surface of the globe could not have consolidated less than ^o 

 millions cf years ago, for the rate of increase of tem[)erature inwards 

 would in that case have been higher than it actually is ; nor more than 

 400 millions of yjars ago, for then there would have been no sensible 

 increase at all." " One hundred millions of years " was regarded by him 

 as the probable amount of time which embraces the Geological history 

 of the globe." 



These calculations, Sir Archibald holds, " may require revision," 

 and states " that there must be some flaw in the physical argument." 

 From his own observations on " degredation " or " denudation," the 

 erosion of rocks and deposition of sediments, he has reached the con- 

 clusion that " the rate of deposition of new sedimentary formations over 

 an equivalent area ot sja-floor, may vary from one toot in 720 3 ears to 

 one foot in 6,800 years." 



Then the " slow progress of organic variation " is discussed, giving 

 its quota of evidence in support of the antiquity of the world. Precise 

 data are wanting in this particular. " We know, says the distinguished 

 geologist, " that within human experience a few species have become 

 extinct, but there is no conclusive proof that a single new species has 

 come i:ito existence, nor are appreciable variations readily apparent in 

 forms that live in a wild state." He then instances the seeds and 

 plants found with Egyptian mummies being precisely the same as those of 

 modern Egypt. This negative evidence, of no change, is an important 

 factor in the problem, and indicates the lapse of an enormous interval 

 of time sufficient to modify forms of shells, etc. 



With reference to this problem and the Ice Age on which Sir 

 Archibald Geikie has so ably and oftimes written, he says : " If the 

 many thousands of yeirs which have elapsed since the Ice Age have pro- 



