504 



Dr. W. B. Carpenter on the Structure [May 16, 



under the name of "Irish G-reen," presented structural characters 

 sufficiently allied to those of the Laurentian Serpentines of Canada, 

 to justify its being referred to the same origin. An examination of 

 numerous decalcified specimens of this rock led me to the conclusion, 

 that although the evidences of its organic origin were by no means such 

 as to justify, or even to suggest, such a doctrine, if the structure of the 

 Canadian Eozoon had not been previously elucidated, yet that the very 

 exact correspondence in size and mode of aggregation between the 

 Serpentine-granules of the Connemara Marble and those of the ' acervu- 

 line ' portion of the Canadian, was sufficient to justify in behalf of the 

 one the claim which had been freely conceded in regard to the other. 



In the following summer, however, it was announced in the ' Eeader ' 

 (June 10, 1865) by Professors King and Bowney of Queen's College, 

 Grabvay, that having applied themselves to the study of the Serpentine 

 Marble of Connemara with a full belief in its organic origin, they had 

 been gradually led to the conviction that its structure was the result of 

 chemical and physical agencies alone, and that the same explanation 

 was applicable to the supposed Eozoon Canadense of the Laurentian 

 Serpentines. This view was afterwards fully set forth in a Paper " On 

 the so-called Eozoonal Eock," read at the Geological Society on the 

 10th of January 1866, and published (with additions) in the Quarterly 

 Journal of the Greological Society for August 1866. The following is 

 their own Summary of their conclusions (p. 215) : — " It has been seen 

 (1) that the ' chamber-casts ' or granules of serpentine are more or less 

 simulated by chondrodite, coccolite, pargasite, &c., also by the botry- 

 oidal configurations common in Permian Magnesian Limestone ; (2) 

 that the ' intermediate skeleton ' is closely represented, both in chemical 

 composition and other conditions, by the matrix of the above and other 

 minerals ; (3) that the ' proper wall ' is structurally identical with the 

 asbestiform layer which frequently invests the grains of chondrodite — 

 that, instead of belonging to the skeleton, as must be the case on the 

 eozoonal view, it is altogether independent of that part, and forms, on 

 the contrary, an integral portion of the serpentine constituting the 

 ' chamber-casts,' under the allomorphic form of chrysotile, and that 

 perfectly genuine specimens of it, completely simulating casts of sepa- 

 rated nummuline tubules, occur in true fissures of the serpentine- 

 granules ; (4) that the ' canal-system ' is analogous to the imbedded 

 crystallizations of native silver and other similarly conditioned minerals, 

 also to the coralloids imbedded in Permian Magnesian Limestone ; 

 that its typical Grrenville form occurs as metaxite, a chemically 

 identical mineral imbedded in saccharoidal calcite ; (5) that the type 

 examples of ' casts of stolon -passages ' are isolated crystals apparently 

 of pyrosclerite. Furthermore, considering that there has been a complete 

 failure to explain the characters of the so-called internal casts of the 

 ' pseudopodial tubules ' and other * passages ' on the hypothesis of 



