22 THE CANADIAN NATURALIST. [Feb. 



rocks, which were altered before the Jurassic dolomites were de- 

 posited. (Bui. Soc. Geol. France [2], vi, 506-516). In like manner 

 we find Scipion Gras concluding from his researches on the 

 anthracitic rocks of the A.lps, that the serpentines, euphotides, por- 

 phyries, and spilites, which are there found associated with crys- 

 talline schists, are all of sedimentary origin, but have been so pro- 

 foundly altered in situ as to have lost nearly all traces of sedimen- 

 tary origin. (Ann. des Mines [5], v, 475.) We might add that 

 the tendency of recent investigations has been to show that the 

 protogines, or granites of the summit of the Alps, are Tertiary strata 

 altered in place ; thus confirming the bold assertion made by Kef- 

 erstein in 1834, that these granites are altered strata oi Jlysch, 

 (This Journal [2], xxix, 123, 124.) Lesley's recent investigations 

 of the granites of the White Mountains of New Hampshire, show 

 them to be clearly stratified sedimentary deposits in nearly hori- 

 zontal layers. (American Mining Journal, 1861,page 99 ; Silliman's 

 Journal [2], xxxi, 403.) The ophites (amphibolites) of the Pyre- 

 nees, which by Dufrenoy and other French geologists have been 

 regarded as eruptive, and were by the former imagined to be in 

 some mysterious manner related to the rock-salt and gypsum of 

 the region, which he supposed to be, like the ophites, of posterior 

 origin to the enclosing strata (Explic. de la Carte Geol. de France, 

 i, 95), are according to a recent note by Virlet, not eruptive, but 

 altered indigenous rocks ; belonging,- together with the associated 

 gypsum and saliferous strata, to the Triassic series. (Comptes- 

 Rendus de I'Acad., Aug. 1863, p. 232). 



It would be easy to multiply examples of this kind, which show 

 that a careful study of very many of the crystalline rocks hitherto- 

 regarded as eruptive, leads to the conclusion that they are really 

 indigenous rocks. At the same time, many of these indigenous 

 rocks appear to have been at one time in a soft semi-fluid con- 

 dition, which permitted movements obliterating the marks of 

 sedimentary origin, and producing other results which show the 

 passage into eruptive rocks. Thus the crystalline limestones of 

 the Laurentian series in Canada are frequently interstratified with 

 thin beds of gneiss and quartzite, both of which are often found 

 broken, contorted, and even twisted spirally, in a manner which 

 indicates great flexi'-ility of the silicious layers, as well as violent 

 movements in the calcareous rock. The latter is in some cases 

 found in the form of thin seams or considerable dykes among the 



