RELATION TO MESOZOIC BOCKS IN THE LEPONTINE ALPS. 191 



an exceptional knowledge of the Alps much experience in field-work 

 in England. For his constant, unwearied, and friendly help I can 

 hardl)' adequatelj^ express my thanks. He was accompanied by his 

 guide, Michel Payot of Chamouni, a shrewd observant man, who took 

 great interest in our investigations and was often very useful. 



We began our work, at Andermatt, by examining the crystalline 

 limestone at the back of Altkirch and the rocks in that neighbour- 

 hood. Thence we crossed the Oberalp Pass to Dissentis, and walked 

 therefrom to the summit of the Lukmanier Pass, where we halted 

 to study the sections on either side (Alp Yitgira and Scopi), localities 

 where fossils were said to occur in schists. Thence we crossed the 

 Passo del Uomo to the Upper part of the Val Piora, where we ex- 

 amined (for the third time in my case) the sections around the Lago 

 di Hi torn. Descending thence to Airolo we investigated the section 

 in the Val Canaria, described by Dr. Grubenmann ; and then, in 

 crossing the IS^ufenen Pass, examined another case of the occurrence 

 of fossils in " schists," reaching the valley of the Rhone by the Egi- 

 uenthal. This concluded the work specially described in this paper, 

 but I may add that we afterwards visited the Binnenthal, in order 

 to verify some points in my former work, and then proceeded to 

 Zermatt. Prom both these localities some valuable information was 

 obtained which bore indirectly on the general questions involved in 

 the investigation. 



The results of our work will, I believe, be made more generally 

 intelligible by grouping them (irrespective of chronological or topo- 

 graphical order) under the following heads : — 



1. The Andermatt Section. 



2. The Schists of the Yal Piora. 



3. The Eauchwacke and its relation to the schists. 



4. The Jurassic rocks containing minerals and fossils. 



1. The AndePvMAtt Section. 



At the base of the slopes leading from the upper valley of the 

 Rcuss to the Oberalp Pass, and not far from the southern opening 

 of the Urnerloch, is a craglet of white marble, which is quarried near 

 a chapel, Altkirch, and can be seen cropping out for some distance 

 up the hill side. This rock is now considered by certain eminent 

 Swiss geologists to be a limestone of Jurassic age, and is so repre- 

 sented on the Andermatt sheet of the Survey map. Specimenc 

 were exhibited at Eurlington House, during the Geological Congress 

 of 1888, to illustrate the supposed transition of this marble into the 

 indubitably Jurassic limestone which occurs in the upper valley of 

 the lleuss, not very far oif the line of strike, at a minimum distance 

 of about 3 furlongs, and can be followed for a long distance west- 

 ward. The evidence of these specimens did not, however, appear 

 to me satisfactory ; for a very wide gap seemed to exist in the chain 

 of demonstration which, from my knowledge of the locality, I believed 

 would be difficult to fill. Put as this identification had evidently 

 been made a basis of correlations of crystalline with sedimentary 



