314 THE CANADIAN NATURALIST. [Jan. 



In the two former respects the specimens from the Calumet and 

 from Burgess approach that now under consideration more nearly 

 than do those from Grenville and Petite Nation ; hut it would he 

 easy, even in the latter, to find occasional instances of a propor- 

 tion of parts similar to that in the present example. General 

 form is of little value as a character in such organisms ; and so 

 far as can be ascertained, this may have been the same in the 

 present specimen and in that originally obtained from the Calumet, 

 while in the specimens from Grenville a massive and aggregative 

 mode of growth seems to have obliterated all distinctness of indi- 

 vidual shape. Without additional specimens, and in the case of 

 creatures so variable as the Foraminifera, it would be rash to 

 decide whether the diiferences above noticed are of specific value, 

 or depend on age, variability, or state of preservation. For this 

 reason I refer the specimen for the present to Eozoon Canadense^ 

 merely distinguishing it as the Tudor variety. 



From the state of preservation of the fossil, there are no crys- 

 talline structures present which can mislead any ordinarily skilful 

 microscopist, except the minute veins of calcareous spar traversing 

 the septa, and the cleavage-planes which have been developed in 

 some portions of the latter. 



I would remark that, as it seemed desirable not to injure any 

 more than was absolutely necessary a unique and very valuable 

 specimen, my observations of the microscopic structure have been 

 made on a few slices of small size, — and that, as the microscopic 

 structures are nearly the same in kind with those of specimens 

 figured in former papers, I have not thought it necessary to pre- 

 pare numerous drawings of them ; while the admirable photograph 

 executed for Sir W. E. Logan by Mr. Notman illustrates suffi- 

 ciently the general form and arrangement of parts (see PI. II.). 



3. Concluding remarks. — In a letter to Dr. Carpenter, quoted 

 by him in the ' Quarterly Journal of the Geological Society ' for 

 August 1866, p. 228, I referred to the occurrence of Eozoon pre- 

 served simply in carbonate of lime. The specimens which enabled 

 me to make that statement were obtained at Madoc, near Tudor, 

 this region being one in which the Laurentian rocks of Canada 

 appear to be less highly metamorphosed than is usual. The 

 specimens from Madoc, however, were mere fragments, imbedded 

 in the limestone, and incapable of showing the general form. I 

 may explain, in reference to this, that long practice in the exami- 

 nation of these limestones has enabled me to detect the smallest 



