PLATE TV. 



The Plate IV sliows the bathometric condition of tlie neigh- 

 bouring seas of the Pescadores or Hoko Gronp. It seems to me 

 that the North Group forms itself an independent centre of 

 extravasation of magma, in contrast to the South or Rover Grouj), 

 from which the Northern is separated by the incurve of the 

 forty fathom-line, — the position indicated by the Rover Channel. 

 Both groups are, however, located at the north-eastern end of 

 the Formosa Bank, which is disconnected on the east from 

 Taiwan by a channel of the same name (j). ']). 



