374 Profs. King and Rowney on 



Skye ? If even the " canal-system " and " nummuline layer " 

 were not present in the latter, Dr. Dawson's description of the 

 lamination of "Eozoon^^ would be sufficient to establish its 

 eozoonal character — as not only do its laminae consist of ser- 

 pentine and loganite, but they are separated by laminge of 

 calcite. As shown in one of our figures*, we have a spe- 

 cimen which might be said, without departing much from the 

 literal truth, to be the counterpart of the "Eozoon mineralized 

 by loganite and dolomite," in fig. 7, page 36 of ' The Dawn 

 of Life.' 



Evasions^ which we are disposed to helieve are unintentional. 

 20th. " The occurrence of the best-preserved specimens of 

 Eozoon canadense in rocks that are ' in a highly crystalline 

 condition ' (Dawson) must be accepted as a fact utterly fatal 

 to its organic origin." This " objection " is answered thus : — 

 " That the occurrence of Eozoon in crystalline limestones is 

 'utterly fatal' to its claims to organic origin can be held only 

 by those w^ho are utterly ignorant of the frequency with which 

 organic remains are preserved in highly ciystalline limestones 

 of all ages." (The remainder of the answer is foreign to the 

 subject). Observe how much our point is incorrectly stated. 

 Nevertheless, as we "feel disposed to treat very tenderly the 

 position " of Dr. Dawson, we shall say nothing more than 

 express a hope that, before indulging in detractions of his 

 opponents, he would endeavour to comprehend the gist of 

 their arguments. 



21st. " The occurrence of ' eozoonal features ' solely in 

 crystalline or metamorphosed rocks belonging to the Lauren- 

 tian, the Lower Silurian, and the Liassic systems — never in 

 ordinary unaltered deposits of these and the intermediate 

 systems — must be assumed as completely demonstrathig their 

 purely mineral origin." Answer — " This limited occurrence 

 is an assumption contrary to facts. It leaves out of account 

 the Tudor specimens, and also the abundant occurrence of the 

 Stromatoporoid successors of Eozoon in the Silurian and 

 Devonian. Further, even if the Eozoon were limited to the 

 Laurentian, this would not be remarkable ; and since all the 

 Laurentian rocks known to us are more or less altered, it could 

 not in that case occur in unaltered rocks." 



The original Tudor specimen, as we have shown (and no 

 attempts have yet heen made in print to invalidate our position)^ 

 may be any thing but eozoonal f ; besides it occurs not " iu 

 an ordinary unaltered deposit," but in a " micaceous limestone 



* Proc. Royal Irish Acad. ser. 2, vol. i. pi. 14. fig. 4. 

 t See Proc. Royal Irish Acad. vol. x. pp. 511, 512. 



