Xlviii INTRODUCTION. 



Eozoon may be presented thus : (1) It occurs in certain layers 

 of widely distributed limestones, evidently of aqueous origin, 

 and on other grounds presumably organic." Our two last para- 

 graphs completely invalidate number one " force ;" but we may 

 add that eozoonal structures also occur in intrusive serpentinyte 

 (Cornwall) . " (2) Its general form, lamination, and chambers 

 resemble those of the Silurian Stromatopora and its allies, and 

 of such modern sessile Foraminifera as Carpenteria and Poly- 

 trema" Mineral developments simulate the eozoonal features 

 mentioned, and so closely, in many cases, that Dr. Dawson 

 has repeatedly admitted that he cannot decide as to whether or 

 not they are organic ! Those who have studied the organisms 

 named repudiate the resemblance stated. " (3) It shows under 

 the microscope a tubulated proper wall similar to that of Num- 

 mulites, though of even finer texture." Reference to the two 

 woodcuts of the " proper wall " of " Eozoon Cana dense " and that 

 ofNunimulites lavigatus (Carpenter, Ann. Mag. N, H. 4th ser. vol. 

 xiii. pp. 457), and our criticisms thereon (op. cit. 4th ser, vol. xiv. 

 pp. 275-280), will completely invalidate this third "force." 

 " (4) Jt shows also in the thicker layers a secondary or supple- 

 mental skeleton with canals." A like phenomenon is common 

 in hemithrenes (Aker, Vosges, &c.). " (5) These forms appear 

 more or less perfectly in specimens mineralized with very different 

 substances." Are the forms, referred to, the "supplemental 

 skeleton " and " canal system" ? If so, their " very different sub- 

 stances" have a pseudomorphic correlation. " (6) The structures 

 of Eozoon are of such generalized character as might be expected 

 in a very early protozoan." This sixth " force " is verily so con- 

 clusive in favour of eozoonism that all opposition to it must cease, 

 now and for ever ! ' ' (7) It has been found in various parts of the 

 world under very similar forms, and in beds approximately of the 

 same geological horizon." The present force requires this addition 

 to its first unit but always in metamorphic rocks, also its second 

 unit corrected thus and in beds of the same rocks of widely 

 separated geological horizQns from the Laurentian to the Liassic. 



