202 WHAT IS LIFE ? 



sembling wolves are found in these layers, as also are 

 found representatives of hedgehogs, squirrels, and bats. 



Thus we see, even in this brief and necessarily im- 

 perfect record, through vast ages, in which we must 

 recognize an unknown number of millions of years, a 

 time to our minds absolutely infinite, does Nature 

 gradually alter its life-forms to a system of organisms 

 which exists at the present day. 



The Eocene formations are found in Britain, France 

 and Belgium, South Europe, India, North America, 

 and Australia. 



Lying on or over and subsequently deposited is a 

 series of layers or strata called by geologists the 

 Oligocene rocks. 



The plant life is composed mainly of evergreen plants, 

 linking them with the living tropical plants of India 

 and Australia. Now parroquets, cranes, eagles, grouse, 

 and other birds appear, reminding us of the lake 

 districts in South Africa. 



The Oligocene strata are found in Britain, France, 

 Belgium, Germany, Switzerland, Italy, and North 

 America. 



Lying upon the above strata and deposited sub- 

 sequently are formed the layers called by geologists 

 the Miocene rocks. 



Animal and plant life marched still further to agree 

 with living life. The forests of these times were 

 tenanted by apes man-like apes, without tails. 



The Miocene rocks are found in France, Germany, 

 Italy, Greenland, India, North America, New Zealand, 

 and Australia. 



Lying upon the Miocene, and deposited subsequently, 

 is a series of layers called the Pliocene rocks ; vege- 



