162 
chosen because it has not previously been much explored botan- 
larly to the limestone, are to be found in the beds of streams. 
Sub-aérial erosion has carried the decayed lava from the slopes 
tion of the island may thus be greater ao during the period of 
volcanic activity. 
eep ravines worn by streams radiate im all directions from 
the mountain masses, cutting through the stratified lower slopes * 
to 
