Tectonic Geography of Eastern Asia. — Hobhs. 375 
"The significance of the strike given, N 20° E, as determining the 
structure of the Taiwan range, is even more sharply brought out when 
one considers an always important factor in the estimation of mountain 
structure, viz.. the courses of the small head streams. . . . It is 
easy to see that the valleys, so far "as they follow the longitudinal di- 
rection, strike; N 15-20° E., and, what appears to be characteristic of 
parallel structure, they are many times joined, to the trunjc streams 
through short cross stretches." 
In the northeastern part of tlie island, however, the direc- 
tion of the rang^es and Hkewise the strike of the beds is east- 
westerly, or almost at right angles to that of the large southern 
portion. This east-westerly structure would seem, moreover, 
to correspond more nearly to the extension of the Riukiu arcs. 
The volcanic zone of the Riukius also extends along the north- 
em coast of Formosa in confirmation of this view. West of 
Formosa, however, the volcanic Pescadores islands trend in a 
direction N 15" E and conform to the tectonic lines as well as 
to the strikes within the greater part of Formosa. 
In the transverse dislocations and in the abnormal strike 
directions characteristic of tlie southern or Sakischima group 
of the Riukius, von Richthofen sees a parellel to the case ex- 
emplified by the island of Crete in the Mediterranean, which 
while clearly a part of an arc that comes out from the Pelop- 
onnesus has tongues of land projecting northward into the sea 
from the western portion of the island, and these are explained 
by cross faults and Grahen depressions along them. 
To sum up, the Riukiu arc and the arc fragments of For- 
mosa diflfer from the arcs of the continental series for the rea- 
son that in the meridional arms, the strikes characteristic of 
the fold structures accord with the lines of depression (Absen- 
kungslinien), whereas, the rule upon the continent is that in 
the meridional arms arc-like dislocations quite generally cut 
across the prevailing strike. In conclusion the author says : 
'"The facts are augmented which for a series of different arcs lying 
to the north of the parallel of 22° in eastern Asia, allow of the conclus- 
ion that the normal structure of those parts of each individual arc 
which are included in the equatorial components, has been brought 
about before that of the meridional components ; and that after the 
arc-like closing together, both the tectonic processes which after sub- 
sequent longitudinal depressions and disruptive longitudinal fractures 
gave to the meridional arms the normal form, extended over in the 
equatorial arms to the arc next adjacent upon the north, bringing about 
there abnormal cross dismemberment and transverse fracturing." 
