1848,] MURCHISON ON THE STRUCTURE OF THE ALPS. 191 



remarkably bold and highly dislocated mountain. From a spot near 

 the Esel summit, where I observed nummulites*, I perceived that 

 there was an ascending section, with a rapid dip to the S.S.E., through 

 beds of impure limestone into highly ferruginous strata, which in parts 

 became a strikingly green calcareous grit (in parts small pisolitic), in 

 which were casts of Pectens and other shells, similar to those associated 

 with nummulites in many other parts of Switzerland. These green 

 sandstones and calc grits there dipped rapidly under a vast thickness 

 of schists, micaceous sandstones and bastard limestones ; in short, 

 imder the *'flysch." It was thus clear that the nummulitic and 

 flysch rocks, though perfectly united and conformable within them- 

 selves, and clearly forming one natural division, were at this high 

 gorge unconformably enclosed between two walls of the older neo- 

 comian limestone, as exhibited in this diagram. In my rapid survey 



Fig. 8. 



Gorge east of Mt. Pilatus. 



g. Flysch of great thickness. 



/. Ferruginous greensand with Pectens (part of the nummulitic group). 



b. Neocomian limestone (upper). 



I did not visit the adjacent flanks of the mountain in which a sequence 

 might be found ; and I have only to observe, that in the great masses 

 of finely laminated marly and sandy schists which descend rapidly on 

 the face of the older limestones into the lake, I found some of the 

 same small foraminifera which MM. Briinner and Riittimeyer have 

 recognized in the environs of Thun. 



On the whole, however, the nummulitic and flysch rocks of the 

 Pilatus have the appearance of having been upheaved in a highly 

 broken and elevated trough, the sides of which rest on the edges of 

 the neocomian limestone, which latter presents to the north one of 

 the finest mural precipices along the whole outer edge of the Alps, to 

 the lower and undulating country of molasse and nagelflue, which 

 here range over the canton of Lucerne. 



The eastern end of the lake of Alpnach is almost barred in by a 

 tongue of land, composed of subcorneal and undulating hills, which 



* The species of nummulite I found in the Pilatus was small, but it is well known 

 that large forms of this genus are there also present. In reference to these 

 organic remains, I ascertained, when in the company of Professor Briinner, how 

 much the species of Nummulites and other Foraminifera differ in the same region 

 at different localities, and yet, as will hereafter be seen, the very same character- 

 istic species reappear at spots very widely distant from each other. 



p2 



