68 



RELICS OF PRIMEVAL LIFE 



Cryptozoon or Eozoon (Fig. 17), and minute car- 

 bonaceous fragments which may be debris of sea- 

 weeds or Zooph}'tes. In rocks of similar age in the 

 United States, Gresley has recently discovered 

 worm-burrows, and in Brittany there are quartzite 

 beds in which Barrois and Cayeux believe that 



Fig. 16. — Casis of Foravdnifera^ from the Htironian of Br ill any. 

 (After Cayeux.) 



Compare with Globigerinae on Fig. 12 and Archaeospherinae, Figs. 50-54. 



they have found tests of Radiolarians, Foraminifera 

 and spicules of sponges, but their organic nature has 

 been denied by Rauff, of Bonn. The casts of Fora- 

 minifera, however, at least appear to be organic 

 (Fig. 16), and it is quite likely that Cayeux may be 



