294 OKIGIN OF CRYSTALLINE ROCKS. [XIII. 



Thus this unproved theory of pseudomorphism, as taught by 

 Bischof, does not, even if admitted to its fullest extent, advance 

 us a single step towards a solution of the problem of the origin 

 of the various silicates which, singly or intermingled, make up 

 beds in the crystalline schists. Granting, for the sake of argu- 

 ment, that serpentine results from the alteration of chrysolite or 

 labradorite, and steatite or chlorite from hornblende, the origin 

 of these anhydrous silicates, which are the subjects of the 

 supposed change, is still unaccounted for. The explanation of 

 this short-sightedness is not far to seek ; as- already remarked, 

 Bischof, although a professed neptunist, starts from a plutonic 

 basis. 



[The notion of the plutonic origin of crystalline stratified 

 rocks has in fact found many advocates, as may be seen by 

 reference to pages of Naumann's Lehrbuch der Geognosie. 

 This learned author himself speaks of them as "those enig- 

 matical deepest-lying rocks which resemble sedimentary strata 

 in possessing more or less perfect stratification, while resem- 

 bling eruptive rocks in mineral composition and crystalline 

 structure" (loc. cit., Vol. II. p. 8, et seq.). He declare* them to 

 be neither sedimentary nor eruptive in the ordinary sense of 

 those terms ; and evidently leans to the notion, of which he 

 speaks with favor, that they are in some way the first-solidified 

 portions of the once molten globe. He elsewhere says that the 

 solidification being from the surface downwards, the lowest of 

 these rocks must be the newest, except so far as eruptive masses 

 may break up through the crust. Tchitatchef, from his recent 

 researches in Asia Minor, holds to Naumann's view as to the 

 plutonic origin of the gneissic rocks of that region. The most 

 recent and most explicit statement of this view of the plutonic 

 origin of these rocks is that put forth T>y Macfarlane, in a 

 learned essay on The Eruptive and Primary Rocks, in the 

 Canadian Naturalist for 1864. He conceives that the structure 

 in these rocks may have been generated by currents in the 

 molten mass of the globe ; and, further, that the once-formed 

 crust may have had a different rate of rotation from the liquid 

 below ; from which also would result a stratiform arrangement 



