THE DAWN OF LIFE 



123 



became a mass of rounded chambers, irregularly piled up in 

 what Dr. Carpenter has termed an " acervuline " manner, and 

 with very thin walls unprotected by supplemental skeleton. 

 Then the growth was arrested, and possibly these upper layers 

 gave off reproductive germs, fitted to float or swim away and 

 to establish new colonies. We may have such reproductive 

 germs in certain curious globular bodies, like loose cells, found 

 in connection with Eozoon in many of the Laurentian lime- 



FIG. 10. Minute Foraminiferal forms from the Laurentian of Long 

 Lake. Highly magnified, (a) Single cell, showing tubulated wall. (, c ) 

 Portions of same more highly magnified. (d) Serpentine cast of a 

 similar chamber, decalcified, and showing casts of tubuli. 



stones. 1 At St. Pierre, on the Ottawa, these bodies occur on 

 the surface of layers of the limestone in vast numbers, as if 

 they had been growing separately on the bottom, or had been 

 drifted over it by currents. They may have served as repro- 



1 It would be interesting to compare these bodies with the forms re- 

 cently found by Barrois and Cayeux in the "Azoic " quartzite of Brittany, 

 which should certainly now be called Eozoic. 



