136 Royal Society : — 



In the first place, the Serpentine-Marble of Connemara, on 

 which their investigations had been chiefly conducted, is admitted 

 by every one who has examined it to have undergone a considera- 

 ble amount of metamorphic change. To myself, as well as to 

 Professors King and Rowney, the evidence which it presents of 

 the operation of chemical and physical agencies is most obvious 

 and conclusive ; whilst the evidence of its organic origin rests 

 entirely on its partial analogy to the eozoonal rock of Canada. 

 Hence an entire surrender might be made of the organic hypothesis 

 as regards the Connemara marble, without in the least degree 

 invalidating the claim of the eozoonal rock of Canada to an or- 

 ganic origin. But, on the other hand, if the latter claim can be 

 sustained, it may be fairly extended to the " Irish Green," should 

 the evidence of similarity be found suflacient to justify such an 

 extension, since it must be admitted by every petrologist that no 

 amount of purely mineral arrangement in a metamorphic rock 

 can disprove its claim to organic origin, if that claim can be 

 shown to be justified by distinct traces, in other parts of the same 

 formation, of organisms adequate to its production. The Carboni- 

 ferous Limestone, various members of the Oolitic and Cretaceous 

 formations, and the Hippurite and Nummulitic Limestones, all 

 exhibit in parts an entire absence of organic structure, which is 

 yet so distinct elsewhere as to justify the generalization that their 

 materials have been originally separated from the ocean-waters by 

 animal agency. And it is well known to those who have studied 

 the changes which recent Coral-formations have undergone when 

 upraised above the sea-level, that a complete conversion of a mass 

 of Coral into a subcrystalline Limestone not distinguishable 

 from ordinary Carboniferous Limestone, may take place under 

 circumstances in no way extraordinary. 



It is, therefore, upon the character of the Serpentine-Limestone 

 of Canada, not upon the nature of the Connemara Marble, that 

 the question of organic origin entirely turns ; and, as I have else- 

 where shown in detail*, the hypothesis of Professors King and 

 Eowney altogether fails to account for the combination of pheno- 

 mena which the former presents, whilst the accordance of that 

 combination with the idea of its Organic origin (a very moderate 

 allowance being made for the efiects of metamorphic change) is 

 such as to establish the same kind of probability in its favour as 

 that which we derive in the case of the Human origin of the " flint 

 implements " from the cumulative evidence of their succession of 

 fractured surfaces, or in the case of the chemical composition of 

 the sun from the precise correspondence between certain dark 

 lines in the solar spectrum and groups of bright lines produced in 

 a dark spectrum by the combustion of certain known metals. 



I may stop to point out, however, that Professors King and 

 Eowney do not attempt to offer any feasible explanation of the 

 fundamental fact of the regular alternation of lamellae of Calca- 



* Quartei'ly Journal of the Geological Society, August, 1866. 



