Structure oj the Austrian Alps, fyc. 89 



become argillaceous and of earthy texture ; the strongest beds 

 of limestone are sometimes highly crystalline, generally of a 

 dark blue colour, and contain innumerable white, contempora- 

 neous veins running in irregular lines transverse to the beds. 

 (2.) Micaceous and chloride slates with a nearly vertical cleav- 

 age, having in many places the structure of primary rocks. 

 (3.) Similar slaty masses, but of more incoherent texture, irre- 

 gularly mixed with calcareous matter, and with calcareous beds 

 generally of a dark blueish colour and of a close subcrystalline 

 texture. This system extends to the bottom of the gorge, and 

 is continued for some way below Lend on the right bank of 

 the Salza. (4.) Fine talcose slate mixed with and passing 

 into serpentine. (5.) A series of beds composed of coarse 

 micaceous slate, sometimes of nearly incoherent texture, mixed 

 irregularly with beds and masses of blueish gray, subcrystal- 

 line limestone, which pass in some instances into a fine, 

 white, crystalline dolomite. (5.) Great masses of grauwacke 

 slate, here and there becoming earthy and passing into shale. 

 (6.) Great beds of limestone, some of them white and cry- 

 stalline, plunging at a high angle into the valley above St. 

 Johann. 



We found no traces of organic remains in this lone- series 

 of deposits, from their commencement above the gorge in 

 the valley of Gastein : but we are convinced, both from their 

 mineral structure and range, that they are prolonged into, 

 and form a part of the system of the Tauern Alp. 



On the banks of the Salza, between St. Johann and Werfen, 

 there are some repetitions of mineral structure similar to those 

 above described ; but on the whole the beds gradually present 

 a coarser and more mechanical texture : the shales are less 

 micaceous and chloritic, and the slaty masses alternating with 

 them often pass into grauwacke. With this change of structure 

 there is a much greater regularity in the dip; the whole of 

 this upper system being carried, by an undeviating inclination 

 towards the north, under the great precipices of secondary 

 limestone. 



A still higher series of rocks on the banks of the Salza are 

 of such a character that it seems uncertain whether they 

 should be referred to the transition or secondary class. They 

 consist of variously coloured shales passing into grauwacke- 

 slate, alternating with greenish gray or reddish fine-grained 

 sandstone; and subordinate to them are some beds of highly 

 calcareous shale and of limestone, in texture resembling some 

 varieties of our transition or mountain limestone. The sparry 

 iron ore of Winterwald, a little south of Werfen, appears to 

 be associated with these ambiguous strata. 



N.S. Vol. 8. No. 44. Am* 1830. N We 



