APPENDIX. 



CHARACTERS OF LAURENTIAN AND 

 HURONIAN PROTOZOA. 



It may be useful to students to state the technical characters 

 of Eozoon, in addition to the more popular and general 

 descriptions in the preceding pages. 



Genus EOZOOK 

 Foraminiferal skeletons, with irregular and often confluent 

 cells, arranged in concentric and horizontal laminae, or some- 

 times piled in an acervuline manner. Septal orifices irregularly 

 disposed. Proper wall finely tubulated. Intermediate skeleton 

 with branching canals. 



EozooN Canadense, Dawson. 

 In rounded masses or thick encrusting sheets, frequently of 

 large dimensions. Typical structure stromatoporoid, or with 

 concentric calcareous walls, frequently uniting with each other, 

 and separating flat chambers, more or less mammillated, and 

 spreading into horizontal lobes and small chamberlets; 

 chambers often confluent and crossed by irregular calcareous 

 pillars connecting the opposite walls. Upper part often com- 

 posed of acervuline chambers of rounded forms. Proper wall 

 tubulated very finely. Intermediate skeleton largely de- 

 veloped, especially at the lower part, and traversed by large 

 canals, often with smaller canals in their interstices. Lower 

 laminas and chambers often three millimetres in thickness. 

 Upper laminsB and chambers one millimetre or less. Age 

 Laurentian and perhaps Huronian. 



