Prof. T. G. Bonney—A/lpine Passes and Peaks. 543 
Moreover, the mouth of the upland glen leading to the Forno glacier 
is as nearly as possible on the level of the Maloya Kulm: its floor 
is reached from the latter by a track which keeps nearly at the same 
level, though the torrent which plunges downwards to the Maira 
has gashed the rock over which it rushes. Hence I believe that the 
streams from the Forno and the Albigna glens formerly flowed into 
the Innthal, as those from the Fédoz and Fex still do, but that, as 
the corrie at the head of the Maira gradually receded in a north- 
easterly direction, it intercepted and diverted, as its floor was on a 
lower level than theirs, first the torrent from the Albigna glen, and 
then that from the Forno. The diversion of these streams would, 
of course, augment the erosive force of the Maira, and correspond- 
ingly diminish the amount of denudation in the upper part of the 
Innthal. Indeed, I think it probable that the torrent from the 
Forno glen has indirectly aided in producing the precipices which 
separate the Maloya Kulm from the floor of the Val Bregaglia. 
Instances like the above are far from rare in the Alps. Most of 
the passes traversed by the great high roads, such as the Genévre, 
the Cénis, the St. Gothard, the Lukmanier, to mention no others, 
furnish us with examples of a nearly level plain of considerable 
extent at their summits; they are, in short, troughs driven through 
the range, not sharp-edged saddles on the range. To all these— 
very difficult to understand on the hypothesis that the watershed 
has always occupied its present position—the above explanation 
may be applied. I will only mention one other case, because it is in 
a region of sedimentary rock, seems no less anomalous than that 
which I have been describing, and brings us to a district where 
another difficulty demands an explanation. 
On the Toblacher plateau—the water-parting between the Rienz 
and the Drave—the Ampezzo road turns off to cross the southern 
range in its course towards Venice. It passes through a deep trench 
in the dolomite mountains. On the one hand rise the grand spires 
of the Drei Zinnen and the turretted wall of the Cristallo; on the 
other the vast altar-stone of the Croda Rossa, with many subordinate 
summits. From Toblach to Landro, from Landro to near Peutelstein, 
the road is almost level. The rise from the entrance to the Hollen- 
steinerthal to the shallow Durrensee, in which the crags of the 
Cristallo are mirrored, is less than 600 feet, though the distance is 
full six miles; and for the remaining six miles the total ascent is 
hardly more than 250 feet. The trough is then suddenly interrupted, 
almost as at the Maloya Kulm. From the northern, or rather the 
north-western side of Monte Tofana, a glen comes sweeping round, 
the floor of which is some hundreds of feet below the level of the 
pass ; to this a steep and narrow track was the only means of descent 
until the present road, with its series of zigzags, was constructed. 
When the floor of this glen is reached, a more gradual descent leads 
to Cortina, which is a little less than 4000 feet above the sea. Here, 
then, we have a repetition, though on a smaller scale, of the physical 
features of the Maloya; and here, also, I can find no other explanation 
of the apparent anomaly than that the watershed once lay rather 
further to the south, and that as the main feeder of the Piave 
