256 JOURNAL OF SCIENCE 
out that, according to Dr. Croll himself, all depends upon the 
snow falling on land, for without land there will be no snow to 
radiate, to reflect, or to form fogs and clouds. Now, in the ant- 
arctic regions there is no great extent of land that is not already 
covered with snow. During the long cold winter of a high ec- 
centricity, the snow would fall into the sea, would be melted and 
work its way towards the equator. Consequently there would 
be no accumulation, and a high eccentricity would not bring on 
a glacial epoch in the southern hemisphere. On the contrary, 
greater cold would probably precipitate the moisture more to the 
north, and so lessen the snow-fall in high antarctic latitudes 
where alone there is land. Possibly therefore the ice would be 
reduced in quantity. Both Mr. Wallace and Dr. Croll* allow 
that high eccentricity alone would not bring on a glacial epoch 
unless the geographical conditions were favourable ; and so they 
would no doubt allow, on reconsideration, that no severe glacial 
epoch could occur in the southern hemisphere under the present 
conditions. In New Zealand more snow might fall in winter, 
but probably it would be all melted again by the greater heat of 
summer ; and, as the mean annual temperature would be higher 
with greater eccentricity, it is not likely that our glaciers would 
be much larger at that time than now. Under the present geo- 
graphical conditions, greater eccentricity might produce a greater 
precipitation of moisture in the form of snow or rain in winter, 
and greater floods in summer, and thereforea diluvial epoch, but 
not a glacial epoch. 
Now there is no reason to suppose that any very important 
geographical changes occurred in the southern hemisphere during 
the pleistocene period ; on the contrary, as will appear presently, 
the insular floras prove long isolation ; but there are several reasons 
for thinking that a diluvial epoch has occurred in New Zealand 
at a comparatively late date: that is during the depression 
which, as we shall presently see, followed our last great glacier 
epoch. These reasons I have lately given in a paper sent to the 
Geological Society,t and I need not reproduce them here, but 
the evidence is not confined to New Zealand alone. 
The Pampzan formation of S. America, so ably described 
by Darwin, which contains the remains of an enormous number 
of huge terrestrial mammals, is much like the so-called “loéss 
formation” of Banks Peninsula and Oamaru, and in both cases 
violent and often-recurring floods sweeping down to the sea 
torrents of mud and the bodies of drowned animals, seem neces- 
sary to account for the phenomena. Also in a letter to me (dated 
June, 1884) Prof. R. Tate says that strong evidence is afforded 
by the distribution of Dzprotodon, that Australia has passed 
through a pluvial period. So that there is evidence in New 
Zealand, in Australia, and in S. America to shew that the last high 
eccentricity of the earth’s orbit may have producedin the southern 
* Phil, Mag. Feb, 1883, p. 81. 
+ Sketch of the Geology of New Zealand, 
