Reviews — King and Roicney on Eozoon Canadcnse. 233 



acquired appetite by eating, since some of them have been pleased 

 to claim that graphic granite, for instance, might be regarded as a 

 metamorphic form of an ancient organic structure. We are less 

 surprised at the eccentricities of Hahn and Reinsch after this. 



The obvious question then presents itself. If " Eozoon " is not 

 organic, what is it? This the authors undertake to answer, and 

 those who wish to know must consult their numerous publications 

 on the subject, and more especially the present one on Rock Meta- 

 morphism. To understand the authors' views it will be necessary 

 to study their terminology, and more especially the meaning attached 

 by them to the word Ophite (=: Ophiolite, or Serpent Stone). After 

 reading the table on page 2, most persons will agree with the 

 authors that "Ophites are not ordinary rocks." 



Having mastered the terminology, it will then be possible for the 

 reader to follow the authors thi-ough the first twenty-one pages 

 of the proper text, where they "dispose of all the serpentinous 

 structures of ' Eozoon Canadense ' in strict conformity with the 

 mutations of all the minerals composing them." In the first place 

 they demonstrate that the typical "nummuline wall" is a pectinated 

 form of chrysotile, due to a modification of that allomorph of serpen- 

 tine, where the fibres of the mineral ultimately become separated 

 aciculee with calcareous interpolations. The " canal system, etc.," is 

 rather more obscure in its origin. It is frequentl}'^ due to the 

 peculiarities of a layer of flocculite (a non-fibrous allomorph of 

 serpentine), which, on undergoing some solvent ordecreting process, 

 is apt to be shaped into irregular configurations. So likewise the 

 "chamber castes" of the acervuline variety are identical with the 

 variously lobulated crystalloids characteristic of Tyree "marble" and 

 similar rocks, due, as the authors believe, to decretion of the original 

 silicate. 



As regards the calcitic layer containing the "intermediate skeleton" 

 in typical specimens of " Eozoon," the calcite composing this part 

 is "plainly a replacement pseudomorph after serpentine." This 

 explanation would account for the alleged cases of " chambers " and 

 " canal sj'stem " preserved in calcite. 



2. Eock substitution, or methylosis. — The term " methylosis " was 

 first proposed by the authors in the Geol. Mag. (Vol. X. p. 19, 1873), 

 and they claim that it has precedence of the " metasomatosis " of 

 Von Lasaulx and Knop. Whichever of the two be ultimately 

 adopted, it is evident that some term is required to express that sort 

 of metamorphism which is accompanied by more or less change of 

 substance. The "metamorphic" rocks — making use of the word in 

 its conventional and more extended sense — may thus be divided 

 into the mineralized, where the original substances have crystallized, 

 and the methylosed, where the constituents have undergone various 

 degrees of chemical replacement, in some cases amounting to entire 

 change of substance. 



It need hardly be said that the views of the authors are totally 

 opposed to those of Sterry Hunt, as recently stated in the Geol. 

 Mag. (1878, p. 466). Messrs. King and Rowney represent the very 



