THROUGH THE GEOLOGIST S EYES 



Then, after a vast interval, there comes a break: 

 something like an end and a new beginning, as if one 

 day of creation were finished and a new one begun. 

 The different formations lie unconformably upon 

 each other, which means revolution of some sort. 

 There has been a strike or a riot in the great mill, 

 or it has lain idle for a long period, and when it has 

 resumed, a different product is the result. Some 

 thing happened between each two layers. What? 



Though in remote geological ages the earth- 

 building and earth-shaping forces were undoubtedly 

 more active than they are now, and periods of de 

 formation and upheaval were more frequent, yet 

 had we lived in any of those periods we should prob 

 ably have found the course of nature, certainly when 

 measured by human generations, as even and tran 

 quil as we find it to-day. The great movements are 

 so slow and gentle, for the most part, that we should 

 not have been aware of them had we been on the 

 spot. Once in a million or a half-million years there 

 may have been terrific earthquakes and volcanic 

 eruptions, such as seem to have taken place in Ter 

 tiary time, and at the end of the Palaeozoic period. 

 Yet the vast stretches of time between were evi 

 dently times of tranquillity. 



It is probable that the great glacial winter of 



Pleistocene times came on as gradually as our own 



winter, or through a long period of slowly falling 



temperature, and as it seems to have been many 



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