MYSORE, CANARY, AND MALABAR. 59 
are arable, and of these a fifth at least produces wet crops. Many CHAPTER 
of the tanks however are ruinous, and their beds are now cultivated 
with Iola, or Holcus Sorghum . 
The strata on these hills are various. I saw red granitic porphyry , strata, 
and took specimens of a fine-grained gneiss consisting of pale red 
felspar , white quartz, and black mica. The most common rock, 
however, is the hornblende slate with quartz , which I have before 
mentioned. When exposed to the air in large high masses, so as 
to prevent the water from lodging on it, the pieces decay into frag- 
ments of a rhomboidal form ; but, when exposed to the air on a 
level with the ground, so as to be penetrated by the rain water, it 
divides into thin laminae, like common schistus. 
t 
