538 



improved by adopting the hypothesis proposed by Professor Milne 

 Edwards to explain the " infiltration of bones and teeth by a process of 

 substitution during the decomposition of their animal contents;" because, 

 although it may be correct in this case, the hypothesis, applied to 

 " Eozoon Canadense," requires the " sarcodic prolongations" to remain 

 distended, elongated, or expanded after death — conditions which it is 

 impossible to conceive, considering that such parts in foraminifers 

 " consist of the softest and most transitory form of living substance" 

 (Carpenter). 



Up to the present time the " replacement" minerals (serpentine, 

 loganite, diopside, chondrodite, &c.) of " Eozoon" have chiefly been 

 found in metamorphic rocks and veins, but never in ordinary unaltered 

 deposits. Nevertheless, Dr. Sterry Hunt has broached the "novel 

 theory" that they have been " directly deposited from th« seas of the 

 time," as " chemical precipitates, which have filled by a process of in- 

 filtration its chambers and canals." 



" In support of this view," the following evidences have been brought 

 forward: — 1st. The deposition of silicates of lime and magnesia from 

 natural waters ; 2nd. u The great beds of sepiolite in the unaltered 

 Tertiary strata of Europe ;" 3rd. u The contemporaneous formation of 

 neolite;" 4th. " Glauconite, which occurs not only in Secondary, Ter- 

 tiary and recent deposits, but also in Lower Silurian Strata. n * 



First. In the " Geology of Canada," 1863, p. 559, it is stated that 

 the " water from Gillan's Spring, inEitzroy, which had been evaporated 

 to one-tenth and filtered, became turbid by further boiling, and gave a 

 flocculent precipitate, which consisted of silica combined with lime and 

 magnesia. A similar reaction was observed with the Yarennes and 

 other saline waters ; and likewise with the waters of the St. Lawrence 

 and Ottawa rivers." Obviously the analogy of these examples (which 

 were only obtained at a high temperature) to the Laurentian " precipi- 

 tates," we are engaged with, is a very questionable and remote one. 



Second. " A hydrous ter- silicate of magnesia, which has been 

 described by the name of sepiolite, occurs associated with limestones 

 and clays of Tertiary age, and of fresh water origin, in Erance, 

 Spain, Morocco, Greece, and Turkey. It is the meerschaum of some 



there is some difficulty that prevents his ridding himself of it ; for he as much as suggests 

 that the " double asbestiform layer," which we brought forward (see our former Paper, 

 PL xiv., fig. 1, p. 194), may have been formed by the spreading out of coalesced 

 bundles of the pseudopodia that have emerged from the chamber wall, just as obtains 

 with the sarcodic layer of recent foraminifers (" Quarterly Journal of Geological So- 

 ciety," vol. xxii., p. 222). Now, as both layers are more or less "compact and indefi- 

 nitely fibrous," they, of " course, are not imitations" (casts), but the coalesced pseudo- 

 pods " themselves turned into stone by Nature's cunning before their destruction by 

 ordinary decomposition!" Respecting this "double asbestiform layer, we have detected 

 more of the kind in Dr. Carpenter's section ; and all of them are only explainable on our 

 view, as elsewhere published. 



* " Quarterly Journal of Geological Society;" vol. xxi., pp. 67, 70, &c. 



* 



