342 animals of the past 



Animal Lifk in the Archean Era 



The word arrhecm means l)egiiining. Therefcjre, this era 

 covers the time of the Ijegiimiug of the eartli's erust and of 

 the formation of the oldest roeks. vVt this time, we hardly 

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

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

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

 know, there were no plants lai'ge 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 lieen found to 

 show that animals existed tlien. If animals did exist in 

 the archean age, they nmst have been small and jirobably 

 had soft l)odies like the amreba and so were not pi'eserved. 



There are some things, however, tliat lead geologists to 

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

 beds of iron ore and crystalline limestone are fovmd in 

 rocks of this era, and the.se ai-e usually formed through the 

 agency of life, l)ut not always. Hence these deposits of 

 iron and limestone are not clear pi'oofs. It is also thought 

 that some very obscure fossils of a low animal have been 

 found; but here again cei'tainty cannot Ix' said to exist. 

 The tiling 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 k)wer tyjies. Now, since it is 

 positively known that animals came into existence through 

 a gradual course of dex-elojiment rather than by a sudden, 

 simultaneous appearance, we shall have to conclude that 

 lih' did exist in Ihe archean ei-a, since it was so abimdant 

 at the beginning of the ])aleozoie. For some reason, all of 

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



