218 PKOF. T. G. BONXEY OX CRYSTALLINE SCHISTS AND THEIR 



Airolo tlie Val Bedretto follows veiy nearly the line of division 

 between the Calc-mica schist group and the Lepontine group 

 (including the Tremola schists). The path leading to the Nufenen 

 Pass for a considerable distance runs near the right bank of the 

 infant Ticino, over schists which belong to — and in many cases are 

 very typical examples of — the calc-mica group, now one, now the 

 other constituent dominating. They are particularly well developed 

 near the entrance of the little hamlet called Fontana. Just after 

 leaving Airolo the path crosses a considerable mass of rauchwacke. 

 It exhibits the usual character, being part of the bed which occurs 

 in the upper part of the Canaria ravine *. After an interval of 

 about 1| mile the rauchwacke again appears in force near Villa, on 

 the left bank of the stream, associated (unless our eyes deceived us) 

 with gypsum. Beyond All'acqua, at the Cantine de Oruina, is 

 another strip of rauchwacke t, and then blocks of the " spotted rock " 

 become common. 



In the upper part of the pass the section from north to south, 

 according to Yon Fritsch, is as follows : — (1) gneiss, (2) rauchwacke, 

 (3) granatiferous rock, (4) Jurassic rock with fossils, (5) granati- 

 ferous rock, (6) calc-mica schist ; the summit of the Kufenenstock 

 (9400 feet) occurring at the junction of (5) and (6): the crags 

 which fall steeply to the pass consisting of (4), while the actual 

 " col," with the greater part of the final ascent on the eastern side, is 

 on (3). The track, from near the Cantine de Cruinato the summit, 

 winds among scattered blocks, chiefly of the " spotted rock." These 

 commonly are of all sizes up to about 8000 cubic feet, but occa- 

 sionally are still larger. The map is coloured as if the rock were in 

 situ, but most of the blocks which we saw formed part of a sort of 

 " trail " or scattered moraine. Some might be in situ, but it was 

 only in a ravine coming from a tributary glen — the Yal Corno, — 

 and near the summit of the pass itself, that we were sure of the 

 occurrence of " live rock ; " the distinction, however, is immaterial : 

 I have no doubt that for all practical purposes the map is accurate 

 enough. But the great mass of the so-called granatiferous rock on 

 the north side of the pass (3), and at the entrance of the Val Corno, 

 the only place where we examined the other band (5), corresponds, 

 not with the Black-garnet schist of the Val Piora, but, in all its 

 essential characters, with the " spotted rock" of Scopi. Perhaps it 

 is slightly more " crystalline " in aspect than the latter, but the 

 difference from the former is marked, as will presently be seen. 

 Fossils are by no means unfrequeut, mainly Belemnites, even in 

 the most crystalline-looking matrix, but good specimens are hard to 

 obtain. The Belemnites are rather shattered ; the rock also is rather 

 harder and tougher than one would anticipate from its mode of 



* It is oontinuoiis with that pierced by the St. Gothard tunnel. 



t Yon Fritsch maps part of this as doloniite. Doubtless he is correct, but 

 we did not attempt to distinguish the dolomitic varieties (which are, I think, 

 usually harder and somewhat more crystalline in aspect) I'rora the oi-diuary 

 rnuchwackc', into which I believe they graduate, because for our purpose the 

 difference was not material. 



