333 



A', B', C' and D' , gaping fractures will appear all along the line 

 A' C' D' B' , which may have helped to form straits. If during their 

 displacement the parts near the surface had at the same time 

 rotating movements, the angles between the old strikes and tiie 

 geanticlinal axis maj' approach zero in the final stage. 



Explanation of the abnormal strikes near the- hending-points. 



The abnormal strike of the island of Babber (fig. 1) may be 

 accounted for by assuming that the deformation of the geanticline 

 at greater depth has been attended with similar horizontal movements 

 near the surface, so that e.g. the geanticlinal portion near the surface 

 of the Teniraber Islands may originally have been situated N.N.E. 

 of Babber, while these parts have since been displaced considerably 

 relative to each other in a horizontal direction. 



When assuming that no horizontal movement has taken place 

 near the surface, the abnormal strike in Babber may also have 

 originated from the great velocity-differences in a horizontal direction 

 at greater depth, with this difference that the submarine geanticlinal 

 part between Babber and the Tenimber-Islands is not disrupted 

 near the surface. If the bending-point is the horizontal projection of 

 a point that gives a minimum in the vertical projection, it may be 

 that near it a large part of the geanticlinal axis is below the sea. 

 In that case data will be lacking for a comparison of the present 

 morphology with the older tectonic structure of the parts on either 

 side of the bending-point. 



Likewise the connection of Halmaheira with the Pelew-Islands is 

 covered by the sea in a considerably area on either side of the 

 bending-point, but in Morotai, where the older strike is oblique to 

 the geanticlinal axis, the geanticline still emerges from the sea, 

 while here the resemblance of the coastline to that of the neigh- 

 bouring part of Halmaheira points to horizontal movements of the 

 islands as such. In the row Formosa-Riukiu Islands (Fig. 3), unlike 

 in the preceding instances, the bend of the older strikes is not 

 covered by the sea, which facilitates a more correct exf)lanation of 

 the phenomenon. The dips in the older formations of the Taiwan- 

 mountains in Formosa point to WNW. movements, those in North- 

 Formosa to southward movements, those in the major part of the 

 Riukiu-Islands to S — E movements. It is evident therefore, that 

 already during the older phases of the orogenetic process, there was 

 a tendency to form a bending-point between Formosa and the Riukiu- 

 Islands. Similar movements during the youngest phase of the mountain- 

 building process gave origin to numerous fractures, e.g. those which 



