76 THE FOSSILS 



crobes, not only in early life, but also in our present environment. 

 This is in clear contrast to the somewhat supercilious way microbes 

 are treated by paleontology. Of course, this attitude, the way in 

 w^hich most paleontology textbooks appear to forget the very ex- 

 istence of microbes, now or in the geological past, stems from the 

 extreme scarcity of fossilized microbe remains. Only under extremely 

 rare circumstances of fossilization, say, silicification or burial in 

 swamps, is there the slightest possibility that microbe remains can be 

 preserved over the lengths of geological time. 



This is an unhappy circumstance, because of the importance mi- 

 crobes have not only in themselves, but for all other life. In our 

 present world they make up three quarters of living matter by sheer 

 weight, whilst they are unsurpassed in the variety of their metabolic 

 processes. Not only that, but many life processes of microbes form 

 the basis of daily functions of the higher organisms. Even if life of 

 the higher organisms is possible without microbes, as seems indicated 

 by experiments under carefully sterilized conditions, and if this were 

 possible in nature also, we might ask with Kluyver: "Is this life as 

 we know it? Is life without microbes really life? Is it worth living; 

 without bread and wine or cheese and beer?" 



Of course, the importance of microbes for early life is even greater, 

 because they also are the evolutionary basis for all later forms with 

 higher organization. It follows that, in our search for the remnants 

 of early life, we must turn away from normal paleontology, which is 

 mainly interested in well-preserved hard parts of higher organisms, 

 which can be nicely classified and interpreted into evolutionary 

 schemata. We must look for remains of early microbes and other 

 forms of life with a low organization, and deduce from their ex- 

 tremely scarce remains the development and history of early life on 

 earth. The scarcity of these remains obliges us to tell our story in 

 but a very general way. 



EARLY PRE-CAMBRIAN REMAINS 



If we go back really further than those late pre-Cambrian organisms, 

 we only have a small number of finds. The earliest, which still are 

 the oldest in absolute age too, are those of lime-secreting organisms, 

 often loosely termed Algae, of South Africa, described by MacGregor. 

 Although quite convincing, this is not a case of real fossils, of struc- 



