266 THE EVOLUTION OF CONTINENTS. 
lower surface—to run aground—on such a shoal situated, 
for example, under what we now call the Soudan, the 
eastern portion would veer around northward, and 
would continue to move in this direction until it either 
ran aground itself, or met some obstacle. 
Inconceivably great seismic forces were at work, and 
from what we know of their action in historic times, we 
may easily believe that a crack or rift might go ina sort 
of zig-zag across the mass. We have seen cakes of ice 
break when floating along, and we all have noticed that 
however crooked the line of fracture, its sides at first 
are parallel, and remain so until the fragments are by 
some means turned more or less around. 
In this immense telluric cake of such ice, the pieces 
beyond the line of separation would be floated west- 
ward. And when the northwestern corner of the upper 
fragment came close to the end of the eastern part, 
which it will be remembered we left moving northward, 
both would be brought to rest, and thus would be pro- 
duced the perpendicularity of the North Pacific coasts. 
The lower end would also be brought to rest should a 
similar shoal be formed under what is now Mexico. 
Like causes would result in South America’s floating to 
its present position, and thus would be produced the 
parallelism of the Atlantic. 
Given then a solidified mass of scorie—in form rudely 
triangular—floating westward in the fluid matter, there 
would be needed only two or three elevated spots on the 
solid, or semi-solid nucleus, to give, with the aid of dis- 
ruptive, seismic forces, the present arrangement of the 
four grand continental divisions.’ 
I have said that, owing to the absence of centrifugal 
force at the poies, it was quite possible that a mass of 
crust remained a longer or shorter time about each. As 
to the northern region, it seems all to have been broken 
1 Europe and Asia being really only one mars. 
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