On the ancient Gi/psum of the Alps. 63 



read before the Institute ia 1807, * he had shewn that 

 mauy transition rocks existed in the Alps, and more par- 

 ticularly in that part of Savoy known by the name of Taren- 

 taise, afFording characters different from those that had at 

 that time been observed in Germany, and containing rocks 

 that had until then been arranged exclusively in the primi- 

 tive series. 



He observes that every subsequent examination had con- 

 firmed him in his first ideas, which had also been approved 

 of by Messrs. Von Buch and Omalius d'Halloy, who had 

 visited the country. 



Notwithstanding his conclusions had been adopted by 

 many celebrated geologists, there were others who still 

 doubted them, in consequence of the total absence of or- 

 ganized remains in the crystalline limestones, which form 

 a considerable portion of these transition rocks. 



The author then states that all the rocks of the Tarentaise 

 were subordinate to two divisions, the limestone formation, 

 and the puddiugstone containing anthracite, or anthracite 

 formation ; in the latter, vegetable impressions were found, 

 but no organized remains had been discovered in the for- 

 mer; his principal proof of its belonging to the transition 

 series, was its alternation with the anthracite formation. + 

 He was most anxious to obtain the last decisive proof (the 

 occurrence of organized bodies) of its belonging to that class ; 

 this however he sought for in vain for a considerable time, 

 when most unexpectedly, he discovered at Paris, with the 

 assistance of M. Leman, a large shell of the nautilite or 

 ammonite kind (plate 2, fig. 1) in a table of the Breche 

 Tarentaise marble, a rock found iu the midst of the district, 

 containing his transition rocks. 



He then proceeds to describe the gypsum occurring in the 

 Alps]. 



* This memoir is inserted iu the Journal des Mines, vol. 23, p. 321. 



+ As the lias, alpine limestone, and new red sandstone formations, are 

 so much altered in the Alps, may this anthracite formation be the repre- 

 sentative of the coal measures? an attentive examination of the vegetable 

 impressions would probably decide this question. (Trans.) 



