HORIZONTAL MOVEMENT OF GEANTICLINES 565 
Asiatic continent are arcs which present their convex sides to 
the oceanic areas. ‘The tension hypothesis of Von Richthofen has 
been applied by some authors to the East Indian Archipelago, but 
the numerous fractures which without doubt exist near the surface 
can be explained in a simpler manner by the action of compres- 
sional stress. 
It is not necessary to distinguish two periods of folding with 
different directions of the compressive forces, if we have regard for 
the fact that the older folds are cut off by the present coast lines. 
If the strike of the older folds is independent of the outlines of the 
present rows of islands, this may be in part a result of a change in 
the direction of the compressive forces; but it can be entirely a 
result of the fact that the folds which now appear at the earth’s 
surface have been formed in a much earlier stage of evolution of 
the geanticline, and that during their elevation the horizontal com- 
ponent of the rate of movement was different for neighboring parts 
of the geanticline, while the transmission of the directed forces has 
increased and the intensity and the direction of the forces 
has changed, whereas at greater depths the plastic deforma- 
tion has continued. 
GROUPS OF SMALL ISLANDS WITH HIGH REEFS 
In many rows of islands the breadth of each island is in direct 
proportion to the amount of elevation. In the Timor-Ceram range 
the long and broad island of Timor shows elevated reefs at the 
altitude of 1,300 m. in its central part, whereas in the short and 
much narrower island of Rotti elevated reefs are known at an alti- 
tude of but 470m. This will generally be true wherever the vertical 
motion prevails. ‘The increase in breadth results from the fact that 
the vertical component of the rate of movement has generally been 
in the same direction near the coast as it has near the axis of the 
geanticline. If the distance of the geanticlinal axis from the coast 
line be considerable, the vertical component of the movement need 
not be the same for longitudinal and for transverse coasts. The 
length of the island may still increase though the breadth decreases, 
or both may decrease and the island get shorter and narrower, while 
the top is still moving upward. However, if the geanticline shows 
