4.28 TRANSACTIONS OF SECTION A. 
remarked: the tapering of America and Africa towards the south, the dispropor- 
tion between the land areas of the northern and southern hemispheres, the excess 
of the oceanic area above the continental area, which occupies but little more 
than one-quarter of the surface; the wide extent of the Pacific Ocean, which with 
the adjoining parts of the Southern Ocean covers nearly two-fifths of the surface. 
Another prominent feature is the antipodal position of continent and ocean. 
South America south of an irregular line which runs from a point near Lake 
Treen ULATUAEAU 
Fig.l. 
Yiticaca to Buenos Ayres is antipodal to a portion of Asia which lies in an 
irregular triangle with corners near Bangkok, Kiaochau, and Lake Baikal; but no 
other considerable parts of the continental system have continental antipodes. 
The Antarctic continent is antipodal to the Arctic Ocean, Australia is antipodal to 
the central Atlantic, and so on. Another notable feature is the skew position of 
South America to the east of North America; South America lies to the east of 
the meridian 85° west of Greenwich; most of North America lies to the west of 
it. But although we may observe prominent general features of the distribution, 
we should find it far from easy to attribute to the form of our imaginary model 
anything that could be called a regular geometrical figure. When we begin to 
think about the removal of material from the parts of the model which are to 
represent oceans and seas, we require a map which gives information about the 
depth of the sea in different places. Around all the coasts there is a margin of 
not very deep water. If some part of the sea could be dried up, so that more 
land was exposed around alljjthe coasts, the area of the surface of the sea would 
be diminished ; and it is known that the depth of water that would have to be 
removed in order to make the area of the sea just half the total area, is abcut 
1,400 fathoms. The contour-line at this depth would divide the surface into two 
regions of approximately equal area-—the continental region and the oceanic 
region. Fig. 2 represents the contour-line at 1,400 fathoms, or the line of separation 
of the continental and oceanic regions. The continental region is shaded. In draw- 
ing this map I have omitted a number of small islands, and I have also omitted a few 
