Structure of the Austrian Alps, fyc. 105 



mites; in which case they generally rise into peaks, weather 

 into peculiarly fantastic forms, and lose all traces of stratifica- 

 tion. From this it would seem, that their mineral structure has 

 originated in some great crystalline action, which commenced 

 after the deposition of the calcareous mass. We must how- 

 ever observe, that the same external forms, the same crystal- 

 line texture, and the same obliteration of all traces of deposi- 

 tory origin, may be found in numberless parts of the chain 

 where the rocks contain no magnesian earth. 



Gypsum is found, in several places, subordinate to the 

 younger Alpine limestone : for example, at Faulenbach near 

 Fussen, where it is extensively quarried. The same mineral 

 is found, near the head of the Kochel See, high in the series, 

 and close to the tertiary plains of Bavaria. It is there as- 

 sociated with black, blue, and red fetid marls, and with fetid, 

 porous rauchwacke, not to be distinguished in external charac- 

 ter from the mamiesian limestone of England. We mention 

 this to show the hopelessness of attempting to determine the 

 age of the different portions of Alpine limestone by mere 

 mineral structure. We may further remark, that gypsum is 

 found in the Alps among secondary rocks of all ages, and is 

 therefore, by itself, no test of the age of any of them. We 

 have already shown, that it exists in the marls inferior to the 

 older Alpine limestone, in the superior saliferous marls, and 

 also among beds high in the series of the younger Alpine 

 limestone: and in former communications we have shown that 

 the same mineral is also found, in considerable abundance, 

 among the tertiary formations of Salzburg and Bavaria*. 



In the extreme prolongation of the calcareous zone into the 

 ridges which terminate the chain a few miles south-west of 

 Vienna, coal- works have been opened, in one or two places, 

 under the direction of Professor Rippl. The coal is of bad 

 quality, and is subordinate to shale alternating with the 

 Alpine limestone. We obtained no fossils from the neigh- 

 bourhood of the works which we visited ; but we suppose, 

 from their position in the chain, that they are in the higher 

 part of the system we are describing. 



One of the most abundant rocks of this series is a peculiar, 

 light-gray, compact limestone, well known to every one who 

 has visited the Alps ; but entirely unlike any secondary rock 



* On the north-western batik of the Walcher See, near the side of the 

 great road from Inspruck to Munich, are traces of some works which were 

 opened about twenty years since in search of quicksilver. We were in- 

 formed that some traces of that metal had been found among the argilla- 

 ceous masses which there alternate with the beds of younger Alpine lime- 

 stone. 



N.S. Vol. 8. No. 44, Aug. 1830. P of 



