202 
ISLAND LIFE. 
[part I. 
proportions had been reversed, large areas of land would 
necessarily have been removed from the beneficial influence of 
aqueous currents or moisture-laden winds ; and slight geolo- 
gical changes might easily lead to half the land surface becom- 
ing covered with perpetual snow and ice, or being exposed 
to extremes of summer heat and winter cold, of which our 
water-permeated globe at present affords no example. We thus 
see that what are usually regarded as geographical anomalies — 
the disproportion of land and water, the gathering of the land 
mainly into one hemisphere, and the singular arrangement of 
the land in three great southward-pointing masses — are really 
facts of the greatest significance and importance, since it is to 
these very anomalies that the universal spread of vegetation 
and the adaptability of so large a portion of the earth’s surface 
for human habitation is directly due. 
