110 Professor T. G. Bonnet/ — 



Northumberland," edited by Mr. Edward Bateson ; it has been lent 

 Avitli the kind permission of the present editor. It shows the Whin 

 Sill breaking across the bedding of sandstones and shales which rest 

 on a bed of limestone; on the left of the picture the Whin has 

 caught up and encloses patches of the shale and sandstone, which 

 have been highly metamorphosed ; the sandstone is light-coloured 

 in the photograph, and two patches of it, immersed in the Whin 

 Sill to the left, can be distinguished by their light colour and by the 

 deep shadow they throw over the underlying shales ; below the 

 further patch to the left the same sandstone and shale are seen 

 in situ below the Whin. The photograph was taken at Cullernose 

 Point on the Northumberland coast. 



IV. — Note on an " Ovenstone " (Talcose-schist) fkom near Zinal, 

 Canton Valais. 



By Prof. T. G. Bonnet, D.Sc, LL.D., F.R.S., V.P.G.S. 



IN the Val d'Anniviers or Einfisch-thal, which joins the Ehone 

 valley at Sierre, the stoves used in warming the houses are 

 often constructed from a stone obtained in the valley. This is so 

 soft that it can be readily cut into shape, but it resists heat 

 remarkably well. According to Gerlach,^ it is obtained at two or 

 three places, but the only one which I have examined is a quarry 

 some height up on the left bank of the valley, rather above Zinal, 

 to which I was conducted by my friend Mr. J. Eccles, who had 

 noticed it during a former visit to this part of the Alps. It is 

 a short distance from the path to the Arpitetta Alp, a favourite 

 excursion for tourists. The result of our examination seems to be of 

 sufficient interest to justify a brief notice.^ 



The quarry is a small one, and the outcrop, so far as we could 

 see, is limited. The rock occurs among a group of schists to which 

 I have more than once called attention, as possessing definite 

 characters and having a great extension in the Alps. The dominant 

 rock is a calc-mica-schist, of which every variety may be found, 

 from a marble or dolomite, practically pure, to a calcareous or 

 even quartzose mica-schist, the last sometimes becoming a very 

 typical quartz-schist. Associated with this is a green schist, 

 sometimes fine-grained and slaty in aspect, sometimes coarser and 

 distinctly foliated. It is often very difficult to ascertain the relations 

 of this green schist to the calc-mica-schist. Occasionally it can be 

 proved to be intrusive, and this is often suggested by its mode of 

 occurrence ; but positive evidence, so far as my experience goes — 

 and I have devoted some time to the subject — is not easily obtained. 

 On the whole, I think that the rock was originally a basalt or 



1 Beitr. zur Geolog. Karte der Schweiz, Lief, ix, pp. 130-1, 142, 173; e.g. near 

 Evolena, L'Allee, and the Moiry Glacier (in another branch of the Val d'Anniviers). 



^ Gerlach, loe. cit. and Lief, xx^di, pp. 87-90, mentions the connection of this 

 "topfstein" -with serpentine, griiner schiefer, and grauer schiefer (the calc-mica- 

 schist), but, if I rightly imderstand him, is not clear as to its origin, or even that of 

 the serpentine. 



