On the calcareo-irappean formations of the 

 southern foot of the Lombard Alps* By 

 Alexandre Brongniart, Metnber of the 

 Royal Academy of Sciences, Sfc 



(Annales des Mines, 1822,) 



THC author describes by this name the formations situated 

 at the southern foot of the Lombard Alps, which are com- 

 posed of calcareous, trappean, amygdaloidal, and basaltic; 

 rocks alternating together, formations previously described 

 by Arduino, and more especially by Fortis, and which are 

 for the most part situated in the Vicentin. 



He does not commence by a detailed account of these for- 

 mations ; he confines himself to mentioning the rocks, their 

 distribution, and the other circumstances which are necessary 

 to prove the truth of the resemblances he considers he is 

 able to establish between these formations and those with 

 which he compares them. M. Brongniart has visited five 

 principal places, the characteristic features of which he no- 

 tices as folloAvs. 



1. The Val Nera. We here see a remarkable alternation 

 of horizontal limestone beds and a small grained trappean 

 conglomerate, which has been named tuf; but as this name 

 very ill applies to rocks which bear no real analogy to each 



• The memoir of which the following extract appeared in the Annales 

 des Mines, was published separately and more at large this year (1823) 

 with the title of Memoiresur les terrains de sediment superieurs calcareo- 

 trappeens du Vicentin, &c. [Trans.] 



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