20 ROCK-METAMORPHISM. 



latter completely prove that they are a genetically identical 

 series, and of purely mineral origin, having no relation to 

 organic structures. No field-mineralogist can look upon the 

 flocculite without seeing at once that it is disintegrated serpen- 

 tine undergoing waste or removal, such as may be seen on rocks 

 of this substance where they are exposed to atmospheric action. 

 Now, disintegrating forces (produced, doubtless, by chemical 

 reactions) having set in, the flocculite of itself must necessarily 

 become more or less a prey to dissolution. Hence we feel certain 

 that the configurations, whether simple, or branching in their 

 form, have been etched out of serpentine or flocculite by chemical 

 processes dissolving or removing this substance : in short, they 

 may be confidently pronounced to be nothing more than 

 "figures de corrosion " of French mineralogists. The beautiful 

 example of " eozoonal canal-system " given in the right corner 

 of the bottom of our figure, though not exhibiting a complete 

 series of the formative changes, is nevertheless of considerable 

 interest as showing it to be an integral portion of a border of 

 flocculite which is significantly penetrated by extensions or 

 lobes of serpentine from the adjacent parent layer*. Configu- 

 rations of the kind are generally white and opaque, with a core 

 of green serpentine ; but frequently they are colourlessly trans- 

 lucent, as is the case with two or three of the branches in this 

 example. 



The process which converted the serpentine into its flocculent 

 variety by entirely removing the latter would affect the plates, 

 lenticuloids, and spheroids, causing their surfaces to be irregu- 

 larly corroded into hollows and projecting lobes. These bodies 

 are regarded as "casts" of the " chambers of eozoon;" but, 

 holding to the view above given, we have no hesitation in rele- 

 gating them, in respect of their origin, to the category of mineral 

 structures. 



In some instances the flocculite has not been removed (see 

 left side of the figure) , but remains as a layer between two other 

 layers of serpentine. 



It will be seen hereafter that there is strong presumptive 



* The example does not belong to the place in which it is represented, but to 

 one close by : it is truthfully represented in its relation to the adjacent border 

 of floccidite. Another example, represented in a former paper (Proc. EOT. 

 Irish Acad. vol. x. pi. xliii, fig. 7), is an intermediate modification. 



