Notices respecting New Boohs. 219 



a. Sub-silacid Ophite?. 

 Chlorargillytes. 

 Agalmatolytes. 



Chlorite-schists, Hydro-phlogopite schists. 

 Talc gneisses (Protogines). 



Peridolytes* (Lherzolyte, Dunyte, Picryte, Ossipyte. &c.) 

 Ophi-euphotides. 



B. SlLO-CAEBACID OPHITES. 



Ophi-calcites. 



Ophi-magnesites. 



Ophi-dolomites. 



b. SubsUo-mrbacid Ophites. 

 Malacolophytes. 

 Hemithrenes. 

 Calci-micaschists. 

 &c. &c. 



Patting aside all questions as to the nature of Eozoon, we con- 

 fess ourselves entirely at a loss to understand the principle of this 

 classification. Clearly it is neither penological nor rnineralogieal. 

 In a work purely chemical, an arrangement which depends solely 

 on chemical composition might be allowable. In certain cases also 

 it might be of advantage to pay regard solely to mineral consti- 

 tuents ; but inasmuch as the scope of the authors' work is, to say 

 the least, distinctly penological, we must protest against one which 

 groups together rocks which not only differ markedly in structure, 

 but also, by the authors' own admission, are sometimes of igneous, 

 sometimes of sedimentary origin. Further, we are at a loss to de- 

 termine what principle underlies the above classification. At first 

 we supposed it to be chemical, and that Ophite, in the authors' 

 minds, was equivalent to " a rock characterized by the presence of 

 minerals containing silicate of magnesia," i. e. in which this is an 

 important constituent; but we are baffled by finding among the 

 members (and that, too, next the " Peridolytes," — i. e. rocks con- 

 sisting mainly of silicate of magnesia), talc-gneisses (Protogines). 

 In the latter, if the authors use the word Protogine in the ordinary 

 sense (i. e. to designate such a rock as we find in the heart of the 

 Mont Blanc massif), even the presence of talc is disputed by some 

 authorities, and in any case it is certainly subsidiary; for the per- 

 centage of magnesia, in all the analyses which we have seen, is 

 extremely small. Such a classification, then, rests on no principle 

 whatever, and is only calculated to throw the student into hopeless 

 confusion, traces, indeed, of which are to be detected in the book 

 itself. The authors do not appear to have clearly made up their 



* We are at a loss to understand why the authors persistently write 

 this word as above. The recognized textbooks always have it Peridotite, 

 or (to follow another spelling of the authors in which they are not always 

 consistent) Peridotyte ; and as it is named from the mineral Peridote, this 

 seems the only possible orthography. Is this an example of methylosis ? 



