1848.] MURCHISON ON THE STRUCTURE OF THE ALPS. 



205 



A glance at this diagram, fig. 17, will sufficiently explain the 



case. TT 1 i-i 



Fig. 17. 



Right bank of the Iller. 

 N.N.E Grunten. S.S.W. 



Kammer-Eck C 



Molasse. 



Fault 



Eocene. 



Blolasse and nagelflue. 

 Flysch. 



Nummulitic limestone alter- 

 nating with flysch. 

 Transition band with Gryphsea. 



Cretaceous, 



b. 



Sonthofen. 



c*cd e f f f g 



Inoceramus limestone or chalk. 

 Green sandstone and gault, 

 , White quartzose sandstone. 

 Upper neocomian limestone 



{Caprotina ammonia). 

 Lower neocomian limestone. 



The lowest visible rocks, as seen in the escarpments on the north 

 and north-east faces of the Grunten {a of fig. 17), are shaly, dark 

 grey, thin-bedded compact limestone, with a little iron and nodules 

 of black flint, alternating repeatedly with dark shale. Some of the 

 beds contain so much chlorite, that, like rocks in two other zones 

 higher in the series, they become grass-green when bruised by the 

 hammer, though previously they are simply dull grey calcareous grits 

 or impure limestones with schists. With the exception of an ammo- 

 nite, M. Brunnerf and myself found no fossils in this rock. There 

 can, however, be no doubt that it is the lower neocomian of Swiss geo- 

 logists, which lithologically it resembles, and like which it graduates 

 up into, and is at once overlaid by, the true upper neocomian, white 

 limestone. The latter rock {b), which, as has been stated, forms so 

 clear a horizon throughout large regions of the external calcareous 

 chain of the Alps, is here, as elsewhere, a thick-bedded, compact, 

 light grey limestone, weathering white in the cliifs ; the surface being 

 distinguished by innumerable white lines, occasionally defining the 

 segments of the shell of the Caprotina ammonia and other fossils. 

 Usually, indeed, these fossil outlines are the hardest portions of the 

 rock, and stand out in the form of chert. Veins of white calc spar 

 also traverse the strata. This white limestone or upper neocomian 

 constitutes the highest point of the double-peaked Grunten, a narrow 

 broken wall of limestone trending from north-east to south-west, the 

 beds of which dip rapidly to the south-west. The consequence is, 

 that in following the top of the crest from these limestone summits to 

 another point called the Hohe Wand, where a cross is erected, and 

 thence down to the highest houses in an upland gorge, called the 

 Gundalpe Hiitte, you pass successively from the neocomian above 

 described to other overlying formations. The rock (c) immediately 

 resting upon the upper neocomian limestone is a lightish grey, 

 brownish, and even a whitish siliceous or quartzose sandstone. Find- 

 ing this rock in other sections on the sides of this mountain, as well 

 as upon the summit, and always in this position, viz. overlying the 

 limestone recognised as the upper neocomian of the Alps ; and, 



t This name has been misprinted Briinner in the preceding pages, 

 VOL. V. — PART I. Q, 



