358 Dr. J. Croll on the Ice of 
and Shetland islands. That the Antarctic ice was formed on 
low and flat land bordered for considerable distances by shoal 
water was the opinion also of Sir Wyville Thomson. 
Assuming then, what seems thus probable, that the Antarctic 
regions consist of low discontinuous land, it will help to explain, 
as will be shown in a future paper, the disappearance of the ice 
during the warm interglacial periods of the southern hemisphere. 
On the Argument against the Existence of 'a South-Polar Ice- 
cap. — We have certainly no evidence that during even the 
severest part of the glacial epoch an ice-cap, like that advo- 
cated by Agassiz and other extreme glacialists, ever existed 
at the North Pole ; I am, however, unable to admit with 
Mr. Alfred E. "Wallace that some such cap, though of smaller 
dimensions, does not at present exist at the South Pole. Speak- 
ing of the Antarctic ice-cap, Mr. Wallace says : — " A similar 
ice-cap is, however, believed to exist on the Antarctic Pule at 
the present day. We have, however, shown that the produc- 
tion of any such ice-cap is improbable, if not impossible ; 
because snow and ice can only accumulate where precipitation 
is greater than melting and evaporation, and this is never the 
case except in areas exposed to the full influence of the vapour- 
bearing winds. The outer rim of the ice-sheet would in- 
evitably exhaust the air of so much of its moisture, that what 
reached the inner parts would produce far less snow than would 
be melted by the long hot days of summer"*. 
This opinion, that the mass of ice is probably greatest at the 
outer rim, which of course is most exposed to moist winds, 
and that it gradually becomes less and less as we proceed 
inwards till at last it disappears altogether, is by no means 
an uncommon one. At the present moment while I write 
(July 9th), Professor Nordenskjold is probably attempting 
to cross the inland ice of Greenland with the hope of finding 
in the interior, hills, valleys, and green fields completely free 
from ice. 
It by no means follows, as some might be apt to suppose, 
that the ice must be thickest where the snowfall is greatest. 
In case of continental ice the greatest thickness must always 
be at the centre of dispersion ; but it is here that, owing to 
distance from the ocean, the snowfall is likely to be least. 
We have no reason to believe that the quantity of snow 
falling, at least at the South Pole, is not considerable. Lieut. 
* 'Island Life,' p. 156. I am unable to reconcile the above altogether 
with what Mr. "Wallace says at page 132, where he refers approvingly 
to my statement that the Antarctic ice-sheet has been proved to be in some 
places at least over a mile in thickness at the edge, and that it must con- 
sequently be far thicker inland. 
