No. 2.] DAWSON — EOZOON CANADENSE. Ill 



4. A fatal defect in the mode of treatment pursued by Mobius 

 is that he regards each of the structures separately, and does not 

 sufficiently consider their cumulative force when taken together. 

 In this aspect, the case of Eozoon may be presented thus: (1.) 

 It occurs in certain layers of widely distributed limestones, evi- 

 dently of aqueous origin, and on other grounds presumably 

 organic. (2.) Its general form, lamination and chambers, 

 resemble those of the Silurian Stromatopora and its allies, and 

 of such modern sessile foraminifera as Carpenterla and Poly- 

 trema. (3.) It shows under the microscope a tubulated proper 

 wall similar to that of the Nummulites, though of even finer 

 texture. (4.) It shows also in the thicker layers a secondary 

 or supplemental skeleton with canals. (5.) These forms appear 

 more or less perfectly in specimens mineralized with very different 

 substances. (6.) The structures of Eozoon are of such general- 

 ized character as might be expected in a very early Protozoan. 

 (7.) It has been found in various parts of the world under very 

 similar forms, and in beds approximately of the same geological 

 horizon. (8.) It may be added, though perhaps not as an 

 argument, that the discovery of Eozoon affords a rational mode 

 of explaining the immense development of limestones in the 

 Laurentian age ; and on the other hand that the various attempts 

 which have been made to account for the structures of Eozoon 

 on other hypotheses than that of organic origin have not been 

 satisfactory to chemists or mineralogists, as Dr. Hunt has very 

 well shown. 



Professor Mobius, in summing up the evidence, hints that Dr. 

 Carpenter and myself have leaned to subjective treatment of 

 Eozoon, representing its structure in a somewhat idealized 

 manner. In answer to this it is necessary only to say that we 

 have given photographs, nature-prints, and camera tracings of 

 specimens actually in our possession. We have not thought it 

 desirable to figure the most imperfect or badly preserved speci- 

 mens, though we have taken pains to explain the nature and 

 causes of such defects. Of course, when attempts at restoration 

 have been made, these must be taken as to some extent conjec- 

 tural ; but so far as these have been attempted, they have con- 

 sisted merely in the effort to eliminate the accidental conditions 

 of fossilized bodies, and to present the organism in its original 

 perfections. Such restorations are not to be taken as evidence, 

 but only as illustrations to enable the fads to be more easily 



