342 animals of the past 



Animal Life in the Archean Era 



The word archean means beginning. Therefore, this era 

 covers the time of the beginning of the earth's crust and of 

 the formation of the oldest rocks. At this time, we hardly 

 dare say how long ago, most of the surface of the earth was 

 covered with water, and there were no varied and forest- 

 covered landscapes to greet the eye. In fact, so far as we 

 know, there were no plants large enough to be visible to the 

 unaided eye. Indeed, it is not certain that any plants 

 existed. The same thing may be said of animals. Almost 

 no sure signs or fossils of animal life have been -found to 

 show that animals existed then. If animals did exist in 

 the archean age, they must have been small and probably 

 had soft bodies like the amoeba and so were not preserved. 



There are some things, however, that lead geologists to 

 think that life did exist in the archean time. For example, 

 beds of iron ore and crystalline hmestone are found in 

 rocks of this era, and these are usually formed through the 

 agency of life, but not always. Hence these deposits of 

 iron and limestone are not clear proofs. It is also thought 

 that some very obscure fossils of a low animal have been 

 found; but here again certainty cannot be said to exist. 

 The thing that can be stated with surety is, that at the very 

 beginning of the next era, the paleozoic, there was an 

 abundance of animals of the lower types. Now, since it is 

 positively known that animals came into existence through 

 a gradual course of development rather than by a sudden, 

 simultaneous appearance, we shall have to conclude that 

 life did exist in the archean era, since it was so abundant 

 at the beginning of the paleozoic. For some reason, all of 

 this life and all of its records have been blotted out. 



