126 THE DAWN OF LIFE 



mental matter that the small rounded organisms already re- 

 ferred to most frequently occur; and while they may be 

 distinct animals, they may also be the fry of Eozoon, or small 

 portions of its acervuline upper surface floated off in a living 

 state, and possibly capable of living independently and of 

 founding new colonies. 



It is only by a somewhat wild poetical licence that Eozoon 

 has been represented as a "kind of enormous composite 

 animal stretching from the shores of Labrador to Lake 

 Superior, and thence northward and southward to an unknown 

 distance, and forming masses 1,500 feet in depth." We may, 

 it is true, readily believe in the composite nature of masses of 

 Eozoon, and we see in the corals evidence of the great size to 

 which composite animals of a higher grade can attain. In the 

 case of Eozoon we must imagine an ocean floor more uniform 

 and level than that now existing. On this the organism would 

 establish itself in spots and patches. These might finally be- 

 come confluent over large areas, just as massive corals do. 

 As individual masses attained maturity and died, their pores 

 would be filled up with limestone or silicious deposits, and 

 thus could form a solid basis for new generations, and in this 

 way limestone to an indefinite extent might be produced. 

 Further, wherever such masses were high enough to be 

 attacked by the breakers, or where portions of the sea bottom 

 were elevated, the more fragile parts of the surface would 

 be broken up and scattered widely in beds of fragments over 

 the bottom of the sea, while here and there beds of mud or 

 sand, or of volcanic debris would be deposited over the living 

 or dead organic mass, and would form the layers of gneiss 

 and other schistose rocks interstratified with the Laurentian 

 limestone. In this way, in short, Eozoon would perform a 

 function combining that which corals and Foraminifera perform 

 in the modern seas ; forming both reef limestones and exten- 

 sive chalky beds, and probably living both in the shallow and 



