1866.] KING AND EOWNEY " EOZOONAL HOCK." 215 



miles in thickness of primary unaltered calcareous argillaceous and 

 mixed deposits in which no vestige of this *' fossil " has been found, 

 and in which its occurrence ought to he certain, had it been a fora- 

 miniferal organisim, — we shall be much surprised if, with such plain, 

 simple, and elementary facts before him, this "creature of the dawn " 

 — the " oldest type of organic life yet known " — does not soon be- 

 come to the geologist a memorable nonentity. 



X. Summary. 



Although zealous advocates at one time for the organic origin of 

 " eozoonal " Ophite, we now, after a prolonged investigation, and 

 after, as we believe, leaving no point unnoticed, feel ourselves under 

 the necessity of totally relinquishing that opinion. 



It has been seen (1) that the " chamber-casts " or granules of ser- 

 pentine are more or less simulated by chondrodite, coccolite, parga- 

 site, &c., also by the botryoidal configurations common in Permian 

 Magnesian Limestone ; (2) that the " intermediate skeleton " is 

 closely represented, both in chemical composition and other condi- 

 tions, 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 separated 

 nummuline tubules, occur in true fissures of the serpentine-granules ; 

 (4) that the " canal-system " is analogous to the imbedded crystal- 

 lizations of native silver and other similarly conditioned minerals, 

 also to the coralloids imbedded in Permian Magnesian Limestone — that 

 its typical Grenville 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 py- 

 rosclerite. 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 ordinary mechanical or chemical infiltration, also bearing in mind 

 the significant fact that the "intermediate skeleton," in Irish and 

 other varieties of " eozoonal rock," contains modified examples of the 

 " definite shapes " more or less resembling the crystalline aggrega- 

 tions and prismatic lumps in primary saccharoidal marbles — that 

 "eozoonal" structure is only found in metamorphic rocks belonging to 

 widely separated geological systems, never in their unaltered sedi- 

 mentary deposits, — taking all these points into consideration, also the 

 arguments and other evidences contained in the present memoir, 

 we feel the conclusion to be fully estabhshed, that every one of 

 the speciahties which have been diagnosed for " Eozoon Canadense " 

 is solely and purely of crystalline origin : in short, we hold, without 

 the least reservation, that, from every available standing point — 

 foraminiferal, mineralogical, chemical, and geological — the opposite 

 view has been shown to be utterly untenable. 



