Dr. W. B. Carpenter on Eozoon canadenae. 469 



the lamellffi ; for it penetrates the Calcareous layers, exactly 

 in the same manner that the Silicates which occupy the 

 chamber-cavities of existing Foraminifera penetrate the walls 

 of those cavities, extending into the canal -system of their 

 " intermediate skeleton," and even filling the minute tubuli of 

 their " proper walls," — so as, when the calcareous skeleton 

 has been dissolved away, to afford the most perfect models, 

 not only of the sarcodic segments which occupied the chambers, 

 but also of their extensions into the canal-system, and even of 

 their minute pseudopodial threads. Xow to all this I can 

 show the most precise parallel in the Canadian Eozoon — even 

 to those departures from the ordinary parallelism of the tubules, 

 which I described in certain varieties of Operculina (Phil. 

 Trans. 1859, p. 24). And I am fully justified, therefore, by 

 the accepted rules of Palasontological interjjretation, in assert- 

 ing that whatever exercise of "Nature's cunning" does this 

 work on our present sea-bottom, was adequate to do it in the 

 Laurentian period. The ex]:)lanation which I suggested, that 

 it is due to a process of chemical " substitution" (the progres- 

 sive decomposition of the sarcode-body producing a precipita- 

 tion of silicates from sea-water, which replace the sarcode, 

 particle by particle), however "unscientific" in the eyes of 

 Professors King and Rowney, has approved itself to Chemical 

 and Palgeontological authorities of considerably higher stand- 

 ing than the Galway Professors, as the only one by which 

 the silicification of fossil wood, and the silicification of the 

 animal substance of recent Corals (described by Di-. Duncan as 

 even now going on), can be accounted for. On the other 

 hand, Professors King and Rowney, to whom I sent, about 

 three years ago, an exquisite little internal cast (in glauco- 

 nite ?) of Polystoniella^ from Captain Spratt's dredgings in the 

 ^gean, with a request that they would give me their opinion 

 of the process by which it was produced, replied that they 

 considered it to be composed of mud ; and though I have re- 

 cently invited them to reconsider tliis opinion, they have not 

 in any way qualified it. Now let these casts, for the sake of 

 argument, be supposed to have been formed by the infiltration 

 of mud, then a like infiltration would equally account for the 

 production of the deposit in the chambers, canal-system, and 

 nummuline tubules of Eozoon^ which \^ precisely paralleled by 

 that of many fossil and existing Foraminifera in regard to its 

 mineral condition — as my specimens show. 



My contention is, therefore, that the hypothesis of the Fora- 

 mimferal origin of Eozoon canadense entirely accords with 

 the features alike of the ^ewera? and of the ?««'/a<<e structure of 



