^^^' 55'] GEOLOGY OF THE DAVOS DISTBIOT. 401 



The Second or Wiesen-Amselfluh Fold. (PI. XXVII.) 



The western margin of the Dacan ' basin ' is formed by the line 

 of Verrucano and Casanna Schiefer which crosses the ridge between 

 the ^IpKhorn and the Leidbachhorn, and thence runs south-west 

 towards Filisur. The dangerous crags of the Leidbachhorn and the 

 slopes that lie below it towards the Landwasser Valley consist of 

 the older crystallines. 



Round Monstein, however, when the solid rock is not hidden by 

 the vast heaps of detrital material here accumulated, typical Casanna 

 Schiefer and below them the Verrucano, which occupies the river- 

 bed from Glaris to Hoffnungs Au, are again found. It is evident 

 that here is the eastern edge of the second fold, the limestone 

 portion of which forms both the long, level ridge of the Alteingrat 

 and the more precipitous rock-wall of the Amselfluh. Along the 

 north-eastern face of this remarkable ridge the stratification is 

 evident from a great distance, and from the lower slopes of the 

 Kummerhubel the line between the Hauptdolomit and the Mittel- 

 bildungen can often be traced by the eye. The Verrucano rises 

 from below the limestone series, following roughly the course of the 

 stream running down to Spinabad from the Mayenfelder-Eurka Pass. 

 It extends northward to form the Kummerhubel and the Schafgrind, 

 and stretches as a broad band across the hillside to Staffel, where 

 the Casanna Schiefer are turned up from below it. 



Though, on the whole, of a conglomeratic character, the Verrucano 

 contains beds of a red sandy shale, while the Kummerhubel itself 

 consists of the red quartz-porphyry already referred to. Above 

 Glaris some excavations made this year (1898) in connexion with 

 i»ew electrical works show that the Verrucano-beds immediately 

 below the limestones are mottled red-and-green shales of the 

 ' Servino ' type. 



It is probable that, as in the case of the Ducan series, a detailed 

 study of the different laj^ers of the Mittelbildungen v^ill repay the 

 labours of future geologists ; and it is probable that the Lithodench'on- 

 kalk will be found somewhere in the Altein region. 



In conclusion, attention may be called to the view from Clavadel. 

 Looking westward from that point, the succession of waves formed by 

 the upturned margins of the formations constituting the Wiesen- 

 Amselfluh fold is very distinct. On the right are the steep, rounded, 

 deeply-incised slopes of the crystalline rocks which culminate in the 

 Korbshorn ; on the left rises the limestone-wall of the Amselfluh, 

 and in the centre the range of serrated peaks representing the Verru- 

 cano-band, with the conical porphyry Kummerhubel as its middle 

 point. Even the zone of the Casanna Schiefer, sweeping round from 

 the Kummerthal under the village of Staffel to the slopes above 

 Frauenkirch, can be to some extent traced by the eye, because of the 

 rapidity with which it weathers and the pale yellow tinge of the 

 resulting soil. 



Q.J.G.S. No. 219. 2d 



