XIV.] THE GEOLOGY OF THE ALPS. 341 



talline because it is composed of crystalline parts derived 

 from some pre-existing crystalline rock." * Emmons also has 

 called attention to the existence of secondary or recomposed 

 beds of talcose, chloritic, and micaceous schists in the Taconic 

 hills of western New England, which, according to him, have 

 been confounded with the older parent rocks. (Ante, page 251.) 

 It would hardly seem necessary to call attention to facts which 

 are familiar to all field-geologists who have worked much among 

 newer deposits in the vicinity of older crystalline rocks, were 

 it not that their significance is so great in connection with 

 Alpine geology. 



This deceptive resemblance to the older crystalline rocks in 

 the Alps, as might be supposed, is not confined to the carbonif- 

 erous. Similar cases are noticed by Favre in the trias, while 

 at the Cols du Bonhomme and des Fours are crystalline aggre- 

 gates also noticed by Saussure as closely resembling the older 

 crystalline rocks, which are shown by the fossils of interstrati- 

 fied beds to be of infra-liassic age. Studer, in opposition to 

 Murchison, maintained that the apparently granitic layers in 

 the flysch (eocene) near Interlaken are but the debris of an 

 older crystalline rock, while the crystalline schists of the Bolghen 

 mountain in the eastern Alps, supposed by Murchison to be in 

 some way interposed in the flysch, are both by Studer and by 

 Boue regarded as merely masses of the older crystalline rocks 

 in a tertiary conglomerate, t 



In discussing the age of the " true crystalline schists " of the 

 Alps, to make use of his expression already quoted, Favre, as 

 we have seen, places them beneath the carboniferous, and in 

 opposition to the suggestion of Murchison and the opinion of 

 Gueymard, that they may be of Cambrian and Silurian age, 

 concludes that we have no proof of the existence of representa- 

 tives of these systems in the western Alps ( 808). In this 

 connection we may note with Favre the presence at Dienten, in 

 the Tyrol, of a Silurian fauna, intercalated in beds of gray and 

 green chloritic schists ( 697 b). The gneiss of Mettenbach, 



* Geol. Transactions (1835), III. 479. 

 t Ibid., III. 334 ; Geol. Jour., V. 210. 



