OPPONENTS AND OBJECTIONS. J 77 



tion whose distribution, age, and structure have been 

 thoroughly worked out by the Canadian Survey, is 

 found to contain thick and widely distributed beds of 

 limestone, related to the other beds in the same way 

 in which limestones occur in the sediments of other 

 geological formations. There also occur in the same 

 formation, graphite, iron ores, and metallic sulphides, 

 in such relations as to suggest the idea that the lime- 

 stones as well as these other minerals are of organic 

 origin. 



2. In the limestones are found laminated bodies of 

 definite form and structure, composed of calcite alter- 

 nating with serpentine and other minerals. The forms 

 of these bodies suggested a resemblance to the Si- 

 lurian Stromatoporae, and the different mineral sub- 

 stances associated with the calcite in the production 

 of similar forms, showed that these were not accidental 

 or concretionary. 



3. On microscopic examination, it proved that the 

 calcareous laminse of these forms were similar in struc- 

 ture to the shells of modern and fossil Foraminifera, 

 more especially those of the Eotaline and Nummuline 

 types, and that the finer structures, though usually 

 filled with serpentine and other hydrous silicates, were 

 sometimes occupied with calcite, pyroxene, or dolomite, 

 showing that they must when recent have been empty 

 canals and tubes. 



4. The mode of filling thus suggested for the cham- 

 bers and tubes of Eozoon, is precisely that which takes 

 place in modern Foraminifera filled with glauconite, 



