692 PROF. T. G. BONNEY ON [Nov. 1902, 
curtain designated the Fee Glacier. If the Allalinhorn, and still - 
more the Alphubel, were not snowy mountains, we might regard 
the higher passes, or 12,500 feet, as the upper limit of the névé 
which supplies the glacier ; but as it is, we will estimate this as 
13,000 feet. 
How far is this huge corrie a cause, how far a consequence of this 
mass of névé and glacier? Let us see what would be the result of a 
rise of temperature of from 6° to 7° Fahr. The effect on the glacier 
would be the same as lowering the whole district by 2000 feet. 
The smaller glaciers would then disappear, the larger be greatly 
‘reduced in volume. But suppose the rise to be 10° Fahr., equivalent 
to an imaginary lowering of 3000 feet; then the principal peaks 
would range from over 10,000 to under 12,000 feet, and the neigh- 
bouring passes would be about 9500 feet. The district, in fact, 
would resemble the Lepontine Alps, from Monte Leone to about the 
Ofenhorn.’’ <A further rise of 4° might be roughly represented by 
taking off another 1000 feet. Then, with only two peaks in the 
Alps overtopping 11,000 feet, with the higher Pennine passes, such 
as are mentioned above, at 8500 feet, and most of those in the 
Oberland well below the snow-line, though a few small glaciers * 
might linger around Monte Rosa and Mont Blanc, these would 
hardly rise above ‘ the second order,’ and over a large part of the 
Alps there would not be so much as a snowfield ; for the snow-line 
would then correspond with what is now 12,000 feet, or only a little 
below the top of the Wetterhorn or the Cima di Jazi. Thus during 
the Oligocene and most of the Miocene Period, when the temperature, 
according to the accepted authorities, was distinctly higher than at 
present, probably some 16° Fahr. in the earlier part, glaciers cannot 
have taken any real share in the sculpturing of the Alps, and even 
permanent snow-beds could only lend a little help in a few of the 
highest regions. At the beginning of the Pliocene Period, when 
the last great series of movements was dying away, the snow-beds 
probably had attained some size, and glaciers had formed under the 
shadow of the higher peaks, which may even have reached their 
present limits soon after the middle of the Pliocene Period. Thus 
in Oligocene and Miocene ages, to speak in general terms, glaciation 
in the Alps was a negligible quantity, its effects coming gradually 
into play in the Pliocene. But for some time many districts would 
be little affected, because with a temperature 6° or 7° Fahr. higher 
than at present there would not be a glacier left between the Simplon 
and the Maloja Passes, and even in the Oberland every one of the 
great ice-streams would have vanished, for then permanent snow 
could only begin at what is now 10,000 feet. On the other hand, if 
the temperature were lowered by the same amount, glaciers would 
1 We can realize the change by (say) estimating Saas Fee at 3000 feet, the 
Schwarzberg-Weissthor as 8850 feet, and Monte Rosa itself as only 12,227 feet, 
or hardly equal to the Mont Velan. 
2 As I have pointed out (‘Ice-Work, present & past’ Internat. Sci. Series, 
1896, pt. iii, ch. 1, pp. 232-33) glaciers in the Alps begin to form about 
1000 feet higher than the snow-line. 
