﻿Vol. 64.] AND ANTIGORITE-SERPENTINES. 153 



Naumann, Hintze, Levy & Lacroix, Tschermak, Brush, Rosen- 

 busch, and Zirkel ; the last adding to a full and precise description 

 an extensive bibliography. But none of these authorities define 

 the locality more exactly : each, as is not unnatural, being content 

 with stating that the mineral came from the Yal Antigorio, though 

 Dr. Hussak and one or two of the later writers have noted its occur- 

 rence in other places. I failed, though some time was spent on 

 the search, to obtain any better information from books on Italian 

 geology,^ or the maps in our Society's Library ; moreover, no 

 serpentine is recorded in the Yal Antigorio on sheet xviii of the 

 Swiss Geological Surv^-map. That, however, hardly amounted to 

 proof of its non-occurrence, because, as this district is in Italy, the 

 map of it would probably be more or less of a compilation. 



The completion of the Simplon tunnel has rendered the Val 

 Antigorio so much more accessible than formerly from the valley of 

 the Rhone, that I determined to end my stay in Switzerland last 

 summer by paying it a short visit. I had once walked up it from 

 Domo d'Ossola on my way to the Yal Bedretto by the San Giacomo 

 Pass, and had no recollection of serpentine,^ but that was so long 

 ago as 1860, and before I paid any particular attention to rocks ; 

 though, as it happened, I had shortly before obtained my first 

 specimen of antigorite-serpentine in the neighbourhood of the 

 Yiso, taking it then as a singular instance of ' a serpentine-schist.' 

 Again, in 1883, I had crossed from the Rhone Yalley to the Tosa 

 Falls by the Gries Pass, returning by the Hohsand Pass and the 

 Binnenthal, without noting serpentine ; but this brought me only 

 into the Yal Formazza, as the upper part of the Tosa Yalley is 

 called, the name being changed without any geographical reason 

 into Yal Antigorio at a little village called Passo.^ The latter title 

 is dropped and that of the Yal d'Ossola assumed at the junction of 

 the Yal di Yedro (down which runs the Simplon road and rail- 

 way).* On the same side, about 10 miles higher up, the Yal Devero 

 comes down from the Geisspfad Pass (leading to Binn), and about 

 2 miles below the Yal di Yedro, that is, a little above Dom^ 

 d'Ossola, the Yal Bognanco descends, not from the watershed of the 



^ Dr. S. Traverse, ' Geologia dell' Ossola ' Genoa, 1895, does not mention 

 antigorite or the occurrence of serpentine in the Val Antigorio, though giving 

 several localities in tributary valleys (including the Yal Vigezzo) vrhere that 

 rock and even peridotites occur. Owing to a singular oversight, I did not 

 make acquaintance with this very full account of the geology of the area 

 drained by the Tosa and its tributaries till after my return, which I regret, 

 though it vrould not have much aided me in my special investigations. 



^ Serpentine is not mentioned by H. B. de Saussure (' Voyages dans les Alpes ' 

 ch. ix), whose description of the scenery and rocks of the Val Antigorio is a 

 model of careful observation. 



^ The sketch-map (p. 154) may make the geographical details more intelligibly. 



* As might be expected, writers differ in the limits assigned to the Val 

 Antigorio. H. B. de Saussure (' Voyages dans les Alpes ' 1796) places the 

 upper one at St. Michel, just below the entrance of the Val Devero ; W. S. King 

 (* Italian Valleys of the Pennine Alps ' 1858, p. 545) carries it a little higher, 

 to about Premia ; John Ball (' Central Alps' 1873 edition, p. 250) puts "it at 

 Foppiano, 2 miles above Passo. I have followed Baedeker (' Guide to Switzer- 

 land ') as a trustworthy authority. 



