Animals Before Man 



of the earth were first extensively studied by 

 English geologists (Sedgwick and Mui'chison) 

 from the abundant outcrop of the rocks of 

 Wales ; hence the names given to the divisions 

 of paleozoic rocks. 



Here, in the Ordovician, life is multiplying 

 in numbers, increasing in diversity of form, 

 moving onward in quality. The progress of 

 life may indeed be compared to the growth of 

 one of those great snowballs boys take such 

 delight in forming, which begins with a ball 

 shaped in the hands, and then as it is rolled 

 along increases more and more rapidly with 

 every turn. So after life was once fairly started 

 every revolution of time added more and more 

 to its varied forms ; first one group of animals, 

 then another sprang into being, until the world 

 was peopled as we see it at present. And just 

 as accidents may happen to the snowball as it 

 is pushed along, here and there a portion crum- 

 bling away and falling by the path, so some 

 animals dropped from among their fellows and 

 have no place in the life of to-day. 



The history of the curious and puzzling 

 70 



