51-2 



else, the motlier-mck has a peridolitic nature: hut in this case there 

 can be no question of iayeis of coal or siiales, broken through by 

 lava, fragments of which possibly could have been taken up in the 

 lava and could be the source of the carbon in the rock. 



The diamond is here a primarj' mineral and even oKler than 

 the olivine. 



The question left to be answered is this: why is the hjperstheiie 

 free from grains of diamond, tiie olivine and anorthite containing 

 them botii? notwithstanding the fact that the hypert-thene crystal- 

 lized after the olivine and before the plagioclase. 



The solution of this question is presumably, that the rock was 

 originally wholly composed of olivine, and that in the cavities, formed 

 l)y resorption, the anortiiite crystallized; (he olivine being resorbed 

 the crystals of <liamond were fieed and suspendeti in the niothei'- 

 liquor; the hypersthene has, by surface-tension, repelled these grains, 

 which were collected in the anorlhile, in which they occur as above 

 stated, on the jilanes of growth or zoiuil structure. This being true, 

 the reaction olivine—»' hypersthene -|- magnetite cannot have occurred 

 in the solid phase because in that case there could have been no 

 reason for the diamond to be dri\en out. 



