190 



PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [DeC. 13, 



(fig. 7). In the countries, however, to which Professor Briinner and 

 myself extended our researches, we perceived the relations of the de- 

 Fig. 7 {hy Pi'ofessor Briinner). 



Gemmen Habkheren 



Roth-horn. Alp. Beattenberg. valley. 



N.W. 



S.E. 



Blolasse. Fault. 



posit to the suhjacent rocks to be much more copious and clear than 

 what he had previously known, and more in harmony with my section 

 at Thones in Savoy. Finally, meeting M. Escher de Linth, I found 

 that this excellent field-geologist had (with the exception of a peculiar 

 band of passage on which I lay great stress) come to the same con- 

 clusion as myself concerning the true position of the nummulitic zone, 

 as being invariably above the inoceramus limestone or representative 

 of the chalk. 



The great zone of limestone, containing Nummulites, Orbitolites 

 and Operculinse, with certain shells, and surmounted by vast accu- 

 mulations of "flysch," i.e. impure limestone, sandstone and schist, 

 extends from the Beattenberg and Habkheren to Alpnach, trending 

 parallel to the major axis of the Swiss Alps, \\z. from W.S.W. to 

 E.N.E. It is, in fact, an elevated trough between the great cal- 

 careous chains of Hofgant, Sernberg and Pilatus on the N.W., and 

 the ridges which flank the lakes of Brientz and Sarnen, the Stanz- 

 horn forming the south-eastern "pendant" to the Mount Pilatus. 

 The depression occupied by the Alpnach branch of the Lake of the 

 four cantons has been essentially formed in the softer schists or 

 marly shale and sandstones of the *' flysch" deposits, whilst the hard 

 calcareous rocks on the flanks of the trough constitute the Pilatus on 

 the one hand and the Stanzhorn on the other. I do not pretend to 

 have so examined Mount Pilatus as to be able to give a detailed de- 

 scription of its structure and relations. I ascended it from Alpnach 

 to the south flank of the Thumli-horn, and thence by a valley, leaving 

 the Eck-horn on the right hand, to the summit, called the Esel, about 

 6000 feet above the sea, devoting the short time at my disposal to 

 the examination of the nummulitic strata and the rocks on which 

 they rest. The chief masses of the mountain are certainly composed 

 of upper neocomian limestone (with Caprotina ammonia) ; and be- 

 tween the Thumli-horn on the one hand, and the Rustiger-wald on the 

 other, I perceived a brownish sandy limestone which strongly con- 

 trasted with the white neocomian limestones of the flanking moun- 

 tains. I saw no traces of gault, upper greensand, or inoceramus lime- 

 stone, but judging from the analogies on the eastern shore of the lake 

 of Lucerne, hereafter to be described, it is probable that such may be 

 found on one of the unbroken shoulders (if such there be) of this 



