IN THEIR ROLE AS WORLD-BUILDERS. 3 



Canada and elsewhere, and we should thus have evidence that 

 even at this early stage of the world's history, the Foraminifera 

 had commenced to play that important part in the formation 

 of strata which they have continued in nearly all the successive 

 periods of geological history, and which is still proceeding in 

 the deep sea to-day. It is no exaggeration to say that, in 

 spite of their diminutive size, the Foraminifera have played, 

 and are still playing, a greater part in building up the crust 

 of the earth than all other organisms combined. 



Dismissing Eozoon for the present as incertae sedis, we find 

 that the only other pre-Cambrian records which can be associated 

 with Foraminifera are the peculiar bodies described by Cayeux (4) 

 from certain quartzites and pthanites of the pre-Cambrian strata 

 of Brittany. These are, however, of such minute size compared 

 with other Foraminifera that their nature cannot be accepted 

 on the evidence hitherto available. 



It appears, therefore, that at present we have no unquestionable 

 records of Foraminifera in pre-Cambrian rocks ; but it is quite 

 possible that such discoveries may be made in the future, as fossils 

 of a higher type have been found, and it seems unlikely that 

 Foraminifera did not, or could not, exist in seas capable of 

 supporting such higher forms of life. 



When, however, we come to the Cambrian strata we find the 

 Foraminifera flourishing, and already marked by numerous widely 

 separated types. So long ago as 1858 Ehrenberg (5) figured 

 some internal glauconitic casts of Foraminifera from a clay near 

 St. Petersburg, which is known to be of Lower Cambrian age. 

 According to Chapman (9) these casts are referable to at least 

 five genera, viz. Verneuilina and Bolivina (family Textularidae), 

 Nodosaria (family Lagenidae), Pidvinulina and Rotalia (family 

 Rotalidae). 



Now it is noteworthy that none of these genera are of simple 

 or primitive types, but are all comparatively complex in the 

 arrangement of their chambers, and representing three distinct 

 types of construction. Hence in this earliest geological record 

 we find the group already well established, and markedly 

 differentiated in structure. No monothalamous or primitive 

 type appears in this earliest list, although we may be sure 

 that they must have been in existence, both then and during 

 antecedent ages. 



