100 Prof. Sedgwick and Mr. Murchison on the 



. Jn several parts of the chain the older Alpine limestone is 

 succeeded by a great series of beds, composed of limestone, - 

 calcareous gritstone, sandstone, and shale. The calcareous 

 beds are often nearly compact, sometimes cherty, commonly 

 separated by thin bands of marl, and offer many varieties of 

 colour and structure. The other members of the system are 

 liable to like variations. The beds of marl, shale, and sand- 

 stone sometimes become greatly expanded ; and the whole 

 system frequently becomes contorted to such a degree, that 

 great masses of brecciated sandstone, shale, &c, are rolled up 

 and enclosed in mountain masses of the limestone we are now 

 describing. To what causes the phenomenon may be due 

 we do not inquire ; but it is, we believe, among such brec- 

 ciated and contorted masses that all the rock-salt of the east- 

 ern Alps has been discovered. The several deposits, com- 

 mencing at Hall, and ranging through Berchtolsgaden, Hal- 

 lein, Halstadt, Ischel, and Aussee, are certainly not now, and 

 probably never were, continuous; but they have all been 

 formed under nearly similar circumstances, and are all nearly 

 on the same parallel. We proceed briefly to notice one or 

 two sections where the true position of the rock-salt is indi- 

 cated ; and for fuller details we must refer to the papers of 

 M. de Lill and other writers on the structure of the eastern 

 Alps. 



(1.) Salt deposit of Hall. (PI. II. fig. 5.) — The accompany- 

 ing section (for which we are indebted to M. Pohringer, Ober 

 Bcrgmcistcr at Hall) shows the true position of the rock-salt 

 among the calcareous mountains on the left bank of the Inn. 

 The whole system has a regular dip of about 30° towards the 

 S.W., and belongs to that part of the secondary chain which, 

 in consequence of an enormous dislocation, seems to plunge 

 under the central axis (see above p. 83). The lowest beds 

 of limestone in the section rise into the peaks of the Lavats- 

 cherberg, in which are found many iridescent Ammonites. 

 They are succeeded by some compact, red beds resembling 

 those immediately below the salt in some other localities. 

 These red beds are surmounted by bands of anhydrite, form- 

 ing the base of a great saliferous mass, composed of green, red, 

 gray, and variegated marls, brecciated masses of sandstone, 

 fetid limestone, &c, in which all appearances of stratification 

 are entirely lost*. The whole thickness of this mass, measured 

 in the direction of the section, is about 1250 English feet: and 



a 



* This position of the anhydrite seems to be nearly similar to that which 

 has been noticed by Charpentier, Bakewell, and other writers on the gyp- 

 seous and saliferous masses in the Alps. 



galleries 



