330 



Islands as far as Kiusjiii tlie strikes are again about parallel to the 

 direction of the row. This example seems to be similar to the two 

 preceding ones, but the areas near Babber, as well as those near 

 Morotai, from which this analogy might appear, are covered by 

 the sea. In Formosa the bending of the older strikes is visible 

 and moreover it can be seen that locally near the bending point of 

 the horizontal projection of the geanticlinal axis the older strikes are 

 normal, or approximately so, to this projection, while on either side 

 they are parallel to it. 



The movemejit at the surface of horizontally moving geanticlines. 



In another publication we have already pointed to the difference 

 in speed and direction of the movements at different depths^). The 

 points, which were originally on the same vertical line, will in a 

 later stage form an irregular curve in space. If the rate of movement 

 has a vertical component, the vertical movement near the surface 

 will be influenced by the vertical movement at greater depth. 



The complicated horizontal and vertical movements, which differ 

 already at a comparatively short distance, will cause new portions 

 of the surface to form the crests of the moving geanticline. The 

 direction of the older strikes with regard to the new geanticlinal 

 axis in a subsequent phase of the movement, will depend upon the 

 rate of movement at greater depth and that near the surface and 

 upon the rate of erosion. 



If the forces, which cause the movement of a geanticline, of 

 which the highest parts rise above the sea-level as rows of islands, 

 are deep-seated, the vertical movements will cause the uplift or 

 subsidence of the islands, while the rale of horizontal movement 

 at greater depth may differ considerably from the rate near the 

 surface. We distinguish two extreme types of movement: 1' The 

 horizontal movement near the surface is equal to zero. 2' The horizontal 

 movement near the surface is similar to the movement at greater 

 depth. In general neither of the extreme types will occur. In the 

 first case no horizontal fracture-movements will take place at the 

 surface, and straits generally correspond with a depression, islands 

 with a culmination of the geanticlinal axis in a given stage of the 

 movement. 



In the second case the islands as such move in a horizontal direc- 



1) H. A. Brouwee, The horizontal movement etc. loc. cit. 

 Id. The major tectonic features of the Dutch East Indies. Journ. Wash. Acad, 

 of Sciences, 1922, p. 172—185. 



