On the so-called “Eozoonal Rock”

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 serpentine are more or less simulated by chondrodite, coccolite, pargasite, &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 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 separated 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 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 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 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 aggregations 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 sedimentary 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 established, that every one of the specialities 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.