OPHITES AND RELATED ROCKS. 19 



integral " nummuline wall/' just as would be the case when 

 the latter was penetrated by the formative pseudopodial pro- 

 cesses of the animal. 



We cannot conceive how any impartial investigator, having 

 an acquaintance with mineralogy, and in face of the evidences 

 placed before him, can resist the conclusion that this " num- 

 muline wall" is the product of structural changes charac- 

 teristic of chrysotile. By way of disposing of these evidences, 

 the advocates of " Eozoon " have made a leap from Scylla into 

 Charybdis. The " nummuline wall," it is argued, has been 

 altered by crystallization and pseudomorphism, so that it, origi- 

 nally lime, has been converted into chrysotile or its modifications. 

 Nay, our " complicated theory of metamorphism " has actually 

 been adopted by Dr. Dawson to explain this " change of calcite 

 into serpentine" and its allomorph, chrysotile which change it 

 appears, he has seen in some specimens of " Eozoon"* \ As to 

 the argument based on the idea that the " nummuline wall " has 

 become accidentally associated with the chrysotile, the fact is of 

 such common occurrence, as are also the concomitant parallelism 

 of the layers showing the two modifications, and the continuity 

 both laterally and lengthwise of their respective aciculas and 

 fibres, as to completely destroy this and any other argument 

 offered in support of eozoonism, based on these considerations. 



A few more remarks on this specimen. Mention has already 

 been made of the serpentine often passing into the flocculent 

 state. In the specimen which has supplied us with the portion 

 last considered, flocculite is rather common in the layers of 

 calcite, filling them here and there (as near the bottom on the 

 left side of the figure), or bordering the serpentine enclosing 

 these layers occurring therein as simple or segmented clotules, 

 which here and there graduate into configurations varying from 

 the simplest rods to much-divided or branching shapes. It is 

 necessary to mention that both the clotules and configurations 

 enclose portions or cores of serpentine. 



The configurations have been taken for casts of tubes pene- 

 trating the calcitic layers, and to represent the canal- system 

 present in the calcareous skeleton of certain existing foramiuifers, 

 But their characteristic irregularity of form, their gradation 

 into the clotules, and their agreement in composition with the 



* See Introduction, A.I>. 1878. 



c2 



