The Plan of the Earth and its Causes. — Gregory. 103 
and Africa (the Eurafrica of Prof. Lap worth) separated by 
the Mediterranean ; Asia and Australasia divided by the 
Malaysian folds. 
Hence the oscillating character of the land, which appeared 
fatal to the old faith in an Earth-plan, helps to justify it, now 
that oceanography and geology have shown us how much to 
allow for the obscuring action of these changes of level. 
But it is inadvisable, in attempting to explain the existing 
plan of the Earth, to introduce any alterations in the distribu- 
tion of land and water. For, although a geologist may have 
no doubt about such assumed changes, he cannot expect geog- 
raphers to have an equal faith in them, or even to take much 
interest in a world thus modified. The geographer is con- 
cerned with the existing arrangement of the world, and not 
with the more or less problematical plans of former ages. The 
introduction of earlier and more primitive geographical sys- 
tems, though it would simplify the question, is unnecessary, 
since the existence of a present Earth-plan is clearly revealed by 
three striking facts. 
GEOGRAPHICAL SYMMETRY. 
Two of these facts are stated in every geographical text- 
book. They are evident on the most casual examination of a 
map. The first is the concentration of land in the northern, 
and of sea in the southern hemisphere. The second is the 
triangular shape of the geographical units. The continents 
are triangular, with the bases to the north. The oceans are tri- 
angular with the bases to the south. Accordingly the land forms 
an almost complete ring round the north pole, and from this 
land-ring three continents project southwards. The oceans 
form a continuous ring round the south pole, and from it 
three oceans project northward into the angles between the 
continents. The belts of sea and land are fixed on the Earth's 
axis like a pair of cog-wheels with interlocking teeth. These 
two belts may be referred to as the northern land-belt and 
southern oceanic-belt. 
The third striking feature in the Earth's physiognomy is 
less conspicuous, but is even more significant. It is known as 
the antipodal arrangement of oceans and continents. It is 
most easily recognized by examination of a globe; but it can 
