504 
Van Else—Earth Movements . 
and extrusions. On the contrary vulcanism seems to be usually 
connected with general uplift of the volcanic districts. If this 
be so, the intruded and extruded material must be compensated 
for by the deep-seated flow from the continental areas or from 
the sea beds. If from the former, no additional effect is pro¬ 
duced upon continental growth, but if from the latter, this gives 
a source of material for continental growth. When it is re¬ 
membered that the majority of the living volcanoes are adjacent 
to the ocean, and that many of the ancient volcanoes have occu¬ 
pied a similar position, it can hardly be doubted that the com¬ 
pensating flow has often, in part at least, come from the sea. 
Where the volcanoes are beyond the main land areas, as in the 
case of the great line of volcanoes extending from the Aleutian 
through the Kurille, Japan, Phillipine and East India islands, 
this position is particularly favorable for continental growth, 
as they are almost immediately adjacent to the deep sea, and 
the epigene agencies rapidly transfer a part of the material to 
the continental slope. 
In the supposed deep-seated flowage of material from the 
oceanic basins towards the lands areas, it is not meant to im¬ 
ply that any part of the material has moved all the way 
to the roots of the volcanoes. As already explained (p. 472), 
the result may be accomplished by a small continent-ward 
movement of a large mass, rather than by a long movement of 
a smaller mass. In the case of the igneous material thus fed to 
a volcano, the movement of any given particle would doubtless 
be slower, the more remote from the volcano, just as that of a 
particle of water in a lake remote from the outlet. However, if 
there be any movement of the material below the bed of the 
ocean toward the land, this is a real source of material for con¬ 
tinental growth. If the continental masses formed during the 
partial or complete solidification of a liquid earth (pp. 479-483), it 
would follow that there was, and perhaps is still, a real cause for 
deep-seated flowage of material from the sea beds toward the land 
areas. It was supposed that after the continents had formed, 
and the first crust under the sea had solidified, the two were ap¬ 
proximately in isostatic equilibrium. After the continents had 
formed, because of the greater thickness of the solidified mater- 
