ON THE FORMATION OF CRYSTALLINE ROCKS. 239 



V Essai de la geographie miner ologique de environs de Paris, Brochant* 

 had signalized, in the most precise manner, the passage of sediment- 

 ary to crystalline rocks, then reputed primitive in the Alps of the 

 Tarentaise. Still later he had the good fortune even to find fossils 

 in them. Applj'ing to these crystalline rocks nearly the same argu- 

 ments which Hutton had used, he concluded that the granular, mica- 

 ceous and talcose limestones, the micaceous, talcose and amphibolic 

 schists of this region of the Alps, were of sedimentary origin, and 

 he referred them to the formations of transition, on account of their 

 analogy to those of German}'. He even went so far as to bring 

 together in the same group the granitic rocks of Mont Blanc and the 

 talcose and feldspathic rocks with which they are associated, and be- 

 lieved he could establish the relatively recent age of these supposed 

 alpine granites. Without adopting the principle of the transforma- 

 tion of rocks, he, nevertheless, contributed, perhaps without knowing 

 it, and with a remarkable clearness and rigor of deduction, to the 

 development of these new ideas, t 



An excursion into the Alps of Glaris, made by Studer and Merian in 

 1826, revealed for the first time a passage of the secondary fomations 

 (flysch) to rocks as crystalline, as the micaschist and gneiss of St. 

 Sothard and Chamouny. | As said Elie de Beaumont, || in a letter 

 that he wrote twelve years later, after having visited the same locali- 

 ties, "We have before our eyes one of the most evident facts of 

 metamorphism in the Alps, and at the same time one of those which 

 best'prove that these phenomena are not exclusively confined to the 

 oldest formations.'' 



Such is, moreover, the important conclusion to which Elie de 

 Beaumont had on his own part arrived, nearly at the same time with 

 Studer, in a careful examination of the Alps of Daupheny and 

 Savo}^, an examination which was of immeasurable importance for 

 geology. He recognized in the graphite of the Col du Chardonnet, 

 which is associated with feldspathic rocks, a result of the transforma- 

 tion of anthracite, § and after a mature consideration he proposed to 

 refer the age of a part of these crystalline rocks to the Jurassic for- 

 mation. 



Thus the prestige of antiquity belonging to the formations of 

 the Alps, w'hich had already been shaken by Brochant and Leopold 

 de Buch, was forever overthrown; and at the same time Elie de 



^Geological observations on the formations of transition of the Tarentaise and other 

 parts of the chain of the Alps. — {Annales des Mines, 1st series, vol. xxiii, p. 321 ; 1808.) 



Considerations on the plnce that the grhnitic rocks of Mont Blanc should occupy in the 

 order of primitive rocks. — (Annales des Mines, 1st series, vol. iv ; 1816 ) 



Discovery of organic fossils in the crystalline rocks. — {Annales des Mines, 1st series, vol. 

 iv; 1819 ) 



■f-Attention was again attracted to the beds which compose the chain of the Alps by the 

 work of Blackwell — (Travels in the Alpine parts of Switzerland and SaiH}y ; 1822.) 



JZeitschiift von Leonkard, vol. xxv, p. I ; 1827. 



ILetter from Elie de Beaumont to Studer, cited in Leonlmrd's Jahrhuch, p. 352 ; 1840. 



§0n the occurrence of vegetable fossils and graphite at the Col de Chardonnet, depart- 

 ment of the Haut Alps. — (Annales des Sciences NatureUes, vol. xv; 1828 ) 



