74 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



paragonite. The mineral changes among these schists are often so 

 marked that, though I do not assert the apparent bedding to be 

 the true bedding, I am compelled to regard the mass as stratified. 

 In any case it is impossible to explain the succession of the stauro- 

 lite schist and the underlying quartzite, both thick masses as 

 clearly defined as any beds of clay and sandstone could be, on any 

 other hypothesis than that of an origin aFstratificati on. In the next 

 series also the evidence is no less strong. Here we have a well- 

 banded series, of considerable thickness, in which the quartzite 

 and the black schist alternate again and again. Now we find a 

 thick band of schist ; now one of comparatively pure quartzite ; now 

 the two are interstratified in layers varying from two or three 

 inches downwards, the black schist often retaining its garnets, and 

 occurring sometimes in continuous bands merely a small fraction of 

 an inch in thickness. In short, whatever association we are accus- 

 tomed to see in a dark shale, and a coarser, more quartzose silt, we 

 can observe it here. Commonly the direction of foliation in the 

 schist agrees with the bedding, and the whole mass seems to have 

 been subsequently compressed in a direction perpendicular to the 

 planes of stratification ; but now and then the rock exhibits won- 

 derful corrugations, apparently subsequent in date to the minerali- 

 zation (or metamorphism) of the whole mass. 



This peculiar melanite schist* is a member, probably one of the 

 lower members, of a great group of metamorphic rocks which have 

 a remarkable extension and development in the Alps. They exhibit, 

 at any rate in this district, characteristics which can be distin- 

 guished, even at a distance ; the chief being the dark but rather 

 ruddy brownish colour which they assume in weathering, and their 

 conspicuously stratified aspect. The latter is so marked that at a 

 distance it is not easy to distinguish them from members of the 

 Mesozoic series. JSfot seldom I have felt doubtful as to their true 

 nature until I had actually taken a specimen in my hand. It then 

 becomes obvious that they are thoroughly crystaUine f. 



Now this peculiar melanite schist, as I have said, occurs near the 

 summit of the Lukmanier Pass ; we find it again in great torce (after 

 getting clear of the ranch wacke) on the upper part of the descent 

 towards Olivone ; and I have picked it up on the summit of the 

 Gries Pass. I believe it has a yet wider extension, but I confine 

 myself to instances where I have myself collected specimens, the 

 localities of which I can only distinguish by the labels. The first 



* Mr. Rideal, Demonstrator of Chemistry in UniTersity College, has kindly 

 ascertained for me that the principal coloiiring-raatter of this dark schist is 

 graphite. Iron-oxide and a trace of manganese are also present. 



t Their effect on the landscape can be nowhere better appreciated than in 

 the noted view from the Bell Alp Hotel. There we see them clearly in the 

 part of the Pennine chain which bounds the valley of the Khone, forming its 

 upper peaks on the eastern side, where they occasionally attain an elevation of 

 from 9000 to 10,000 feet above the sea, and they then come sweeping down 

 towards the valley, until, about the foot of the Simplon and the mouth of the 

 Vispthal, they form the subordinate outer peaks and the lower slopes of the 

 range. 



