ORIGIN OF CHARACTERS OF OPHITES AND RELATED ROCKS. 13 



of peridote and feldspar may be safely assumed to be genetically 

 identical with that of chrysotile, taking the incipient variety of 

 the latter into consideration ; moreover, we hold it to be in all 

 three a superinduced divisional structure. In short, the fibrous 

 laminae of peridote and feldspar have as much right to bear a 

 distinctive name as the fibrous allomorph of serpentine. 



Reverting to the alternation of two distinct minerals, viz. 

 feldspar and quartz, in the graphic granite of Harris, the case 

 affords a parallel to the interlamellation of the serpentine and 

 calcite in the Archaean ophites, as already noticed. The same 

 phenomenon is also instructively displayed in ared quartzose 

 feldspathic rock from Siberia, of which a portion is represented 

 under fig. 6, Plate I. The layers of quartz and feldspar exhibit 

 such a definite alternation that in this respect the calcareo-ser- 

 pentine interlamellation of the "eozoonal" ophi-calcite of Canada 

 does not surpass it. The remarkable character last referred to, 

 which first gave rise to the idea that it is due to organic forma- 

 tion, does not, according to Dr. Dawson, occur in any rock of 

 purely mineral origin ; the instances already adduced will show 

 that this is an entirely erroneous statement*. Besides, we are now 

 in a position to demonstrate more clearly our point ; Professor 

 Heddle having kindly placed in our hands a remarkably beau- 

 tiful specimen, from another locality, Tarbert, in Harris, which 

 consists of white quartz and a silvery feldspar (? moonstone), 

 alternating so definitely as to be identical in this respect with 

 the interlamellation of serpentine and calcite in type specimens 

 of "Eozoon Canadense " f . No wonder that this lamellar graphic 

 granite has been pronounced to be of organic origin by believers 

 in the eozoonal doctrine % \ 



But it may be urged that in these examples the alternation 

 consists of two siliceous minerals. Granted. Still we are able to 

 dispose of this objection. There is a large specimen from near 

 Vigan, Department du Gard, under a glass shade in the centre 

 of the Geological Museum of the Jardine des Plantes, and 

 another one in a wall-case from the Pic d'Eridlitz, Pyrenees, 

 both consisting of feldspar and calcite definitely interlamellated . 



* See Introduction, A.D. 1879, 



t See Plate IX. fig. 3. t See Introduction, A.D. 1876. 



M. Edouard Jannettaz very kindly showed me the specimens. The 

 Vigan specimen, according to its label, Was procured by M. Cordier. 

 W. K. 



