308 THE CANADIAN NATURALIST. [Jan. 



supposed to belong to the unconformable Upper Laurentian, thus 

 showing that the specimens of Eozoon of this neighbourhood, like 

 those previously discovered and described, belong to the Lower 

 Laurentian series. 



The Tudor limestone is comparatively unaltered ; and, in the 

 specimen obtained from it, the general form or skeleton of the 

 fossil (consisting of white carbonate of lime) is imbedded in the 

 limestone, without the presence of serpentine or other silicate, the 

 colour of the skeleton contrasting strongly with that of the rock. 

 It does not sink deep into the rock, the form having probably 

 been loose and much abraded on what is now the under part, 

 before being entombed. On what was the surface of the bed, the 

 form presents a well-defined outline on one side ; in this and in 

 the arrangement of the septal layers it has a marked resemblance 

 to the specimen first brought from the Calumet, eighty miles to 

 the north-east, and figured in the ' Geology of Canada,' p. 49 ; 

 while all the forms from the Calumet, like that from Tudor, are 

 isolated, imbedded specimens, unconnected apparently with any 

 continuous reef, such as exists at Grenville and the Petite Nation. 

 It will be seen, from Dr. Dawson's paper, that the minute 

 structure is present in the Tudor specimen, though somewhat 

 obscure ; but in respect to this, strong subsidiary evidence 

 is derived from fragments of Eozoon detected by Dr. Dawson in a 

 specimen collected by myself from the same zone of limestone 

 near the village of Madoc, in which the canal-system, much more 

 distinctly displayed, is filled with carbonate of lime, as quoted 

 from Dr. Dawson by Dr. Carpenter in the Journal of this Society 

 for August, 1866. 



In Dr. Dawson's paper mention is made of specimens from 

 Wentworth, and others from Long Lake. In both of these local- 

 ities the rock yielding them belongs to the Grenville band, which 

 is the uppermost of the three great bands of limestone hitherto 

 described as interstratified in the Lower Laurentian series. That 

 at Long Lake, situated about twenty-five miles north of Cote St. 

 Pierre in the Petite Nation Seigniory, where the best of the 

 previous specimens were obtained, is in the direct run of the 

 limestone there ; and like it the Long Lake rock is of a serpentinous 

 character. The locality in Wentworth occurs on Lake Louisa, 

 about sixteen miles north of east from that of the first Grenville 

 specimens, from which Cote St. Pierre is about the same 

 distance north of west, the lines measuring these distances running 



