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PRESIDENTS ADDRESS. 
northern and southern regions of our globe may be due, we have 
a right to demand from the astronomers and physicists the conces- 
sion, that mild interglacial periods of considerable duration must 
have prevailed at or near the poles, certainly within Tertiary times. 
Sir Robert Ball says : “ It is essential to the astronomical theory of 
the Ice Age that such interglacial and glacial periods must have 
alternated with one another at the opposite poles of our earth.” 
The facts of the occurrence of extensive beds of coal and lignite, 
associated with shale-beds rich in leaves of dicotyledonous trees 
and shrubs in Arctic America, in North Greenland, Spitzbergen, &c., 
within the Arctic circle ; and beds of coal with abundant tree- 
trunks in Kerguelen’s Island,* Chatham Islands,! &c., in the 
Antarctic, where no trees now exist, testifies to great changes of 
temperature in the circumpolar regions of our earth, such as would, 
if they recurred, render these lands again habitable by plants 
and animals belonging to warmer temperatures, and greatly reduce, 
if not entirely remove, all traces of snow and ice over these 
areas. 
Let us take a glance at the two polar regions of our earth. 
First : let us note the fundamental difference between Arctic and 
Antarctic conditions as regards topography. 
In the Northern Hemisphere there is a polar sea almost com- 
pletely surrounded by continental haul, and continental conditions 
for the most part prevail. 
In the Southern Hemisphere there is almost certainly a continent 
at the South Pole, which is completely surrounded by the ocean, and 
the most simple and extended oceanic conditions are met with. 
Below the parallel of 40° South latitude, lie, Tasmania, the South 
Island of New Zealand, numerous small Islands (such as the 
Chatham Islands, Auckland Island, Campbell Island, Kerguelen 
Island, Heard Island, Prince Edward Islands, Tristan da Cunha, 
Gough Island, Bouvet Island, South Georgia, Sandwich Group, 
South Shetland Islands, Falkland Islands), and about 1500 miles 
linear of the South American Continent and Cape Horn. At the 
pole itself lies the great unexplored Antarctic Continent, surrounded 
* 50° S. Lat. Kerguelen’s Island. + 45° S. Lat. (Chatham Islands). 
