Yol. 55.] GEOLOGY OF THE DAYOS DISTRICT. 385 



paper. He omitted to note that the ' hornblende-schists ' and other 

 characteristic rocks of the eastern side of the valley occur also on 

 the Dorfliberg and the Korbshorn. 



(ii) The Biindner S chief er. 



The term ' Biindner Schiefer ' has been used in different senses 

 and with changing comprehensiveness by various writers. While 

 referring chiefly to the great series of contorted grey argillaceous 

 and calcareous strata which stretch across Graubiiuden from Chur 

 to the Oberhalbstein and from the Rhatikon to the Upper Yorder- 

 rheinthal, the name originally covered also the red-aud-green 

 schists associated with the serpentine, with the cherts, hornstones, 

 and variolites. In Theobald's memoir of this part of Graubiinden 

 the term is used in this liberal sense. Steinmann, in his paper on 

 the age of the Biindner Schiefer, has wisely proposed its restriction ; 

 and in the following pages the name will be applied only 

 to those strata which lie beyond the western limit of 

 the dolomite and its associated rocks. The strata which 

 form the Western Rhatikon and the Schanfigg, cut through by the 

 Landquart and the Plessur, consist of typical Biindner Schiefer in 

 this restricted sense. They are, in the main, dark clayey shales 

 locally seamed with calcite. The upper layers contain distinct beds 

 of flaggy limestone, and even thick and massive calcareous reefs. 



Despite the labours of many geologists, the age of the series is 

 still a matter of great difficulty and uncertainty ; and, as the 

 present paper adds nothing to the controversy, it is unnecessary to 

 go further into a description of the Biindner Schiefer. As is well 

 known, the shales in some parts contain numerous fucoids, and these 

 are usually regarded as of Tertiary age and referred to the Flysch. 

 In other localities the discovery of ammonites and of bodies believed 

 to be much-altered belemnites points to a Jurassic age, which on 

 other grounds seems probable for a part at least of the series. 

 Steinmann has tried to show that in some localities the line 

 between the Tertiary and Secondary strata can be traced, and it 

 may be that his conclusions will be confirmed by more detailed 

 work, but the lithological similarity of strata of such different ages 

 remains very difficult to understand. 



(iii) The Triassic System. 



After leaving the difficult problem of the grey Biindner Schiefer, 

 we find ourselves on less uncertain ground in dealing with the pre- 

 Jurassic strata. Taking them in consecutive order from above 

 downward, it is found that 



(1) The Rhsetic are the only beds characterized by definite 

 fossils,^ though within our area these are few and generally crushed 



^ The only other fossils with which I am acquainted in the whole district 

 are crinoid-fragments in the detritus on the Mayenfelder-Furka Pass, doubtless 

 derived from the ' Mittelbildungen.' 



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



