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liberal interpretation of this doctrine might have been easily determined 
by consulting the last edition of his manual (pp. 737, 1019), where it is 
seen that he accepts, as probable, former extensions of land in the Southern 
Hemisphere by which all of the now isolated land masses were connected. 
That a present belief in the strict permanerice of the continental outlines 
is not shared by many geologists, especially by Europeans, is indicated by 
the paleogeographic maps in many books and articles, among which may 
be singled out the Traité de Géologie by A. de Lapparent (1911 pages; fourth 
edition, 1900). 
Such maps are largely based upon paleontological evidence from many 
groups of animals and plants, and consequently appeal most strongly to 
the paleontologist, but that there is structural evidence for the view of 
former extensions of the continental platforms beyond their present limits 
may be gleaned from the monumental work of Suess, Das Antlitz der Erde. 
In view of these statements, it may be said that it is the opinion of 
many well-qualified geologists that, while no large areas of oceanic basins 
have been uplifted and added to the continental platforms, there has been, 
on the contrary, an intermittent but progressive continental fragmenta- 
tation through geological time by which land masses, most notably Antarc- 
tica, have been isolated and reduced in size, and the area of the oceanic 
basins correspondingly increased. The consequent enlargement of volume 
of those basins has tended to drain the shallow seas from the continental 
platforms and cause an intermittent but progressive emergence of the 
lands. Relative vertical movements of the oceanic segments and erosion 
of the lands have, however, also been major factors further complicating 
the result. The only known limitations to such changes of continental 
relations appear to be given by the general maintenance through geologi- 
cal time of the critical relations of the sea-level to the continental surfaces, 
and if, as seems probable, the volume of sea-water has increased through 
time, the area of the continental ptalforms may, in somewhat like meas- 
ure, have decreased. These views affect the present hypothesis of the 
place of origin of the moon in two ways: by indicating that the Atlantic 
and Pacific may not always have possessed their present forms; but 
further, and more importantly, that the causes of the existence of ocean 
basins and continental platforms are not to be found alone in a primal 
cause no longer acting, but, to a considerable extent at least, to still acting 
and persistent causes. 
Interesting consequences of certain suggestions put forth may be seen 
by comparing the last paragraphs on pages 32 and 33 respectively. The 
logical conclusion from these is that the ocean basins, formed by the break- 
