234 THE CANADIAN NATURALIST. [Vol. ix. 



not even studied the principal collections on which other natur- 

 alists equally competent have based their conclusions, they incur 

 a responsibility much more grave than if they were merely the 

 conductors of a popular scientific journal, open to cursory dis- 

 cussions of controverted points. They cannot relieve themselves 

 from this responsibility till they shall have published a really ex- 

 haustive description of Uozoon by some one of the original workers 

 on the subject. This is the more necessary, since if Eozoon is 

 really a fossil, its discovery is one of the most important in 

 modern palaeontology, and since its claims cannot be settled 

 except by the most full investigation and illustration. 



The second paper referred to above contains little that is new, 

 being a re-habilitation of that hypothesis of " Methylosis," or 

 chemical transmutation, which the authors have already fully 

 explained in the Transactions of the Irish Academy and else- 

 where. Its bearing on Eozoon is simply this : — that if any one 

 acquainted with geological and chemical possibilities can be in- 

 duced to believe that the Laurentian limestones of Canada are 

 " Methylosed products," which originally " existed as gneisses, 

 hornblende schists, and other mineralised silacid metamorphics," 

 he may be induced also to believe that Eozoon is a product of 

 merely mineral metamorphism. 



When we consider that these great limestones have been so 

 fully traced and mapped by Sir William Logan and his succes- 

 sors on the Geological Survey ; that some of them are several 

 hundreds of feet in thickness and traceable for great distances, 

 that they are quite conformable with the containing beds, and 

 themselves exhibit alternating layers of limestone and dolomite, 

 with layers characterized by the presence of graphite, serpentine, 

 and other minerals, and subordinate thin bands of gneiss and 

 pyroxene rock, the idea that they can be products of a sort of 

 pseudomorphism of gneisses and similar rocks, be<3omes stupend- 

 ously absurd, and can only be accounted for by want of acquaint- 

 ance with the facts on the part of the authors. 



To explain the structures of Eozoon^ however, even this is not 

 altogether sufficient, but we must suppose a peculiar and complex 

 arrangement of laminae, canals, and microscopic tubuli or fibres 

 simulating them, to be produced in some parts of the limestones 

 and not in others ; and this by the agency of several diflFerent 

 kinds of minerals. 



In other words we have to suppose a conversion on a gigantic 



