Table Lands of South India. 315 



ly conglomerated together with grains of felspar and quartz 

 perfectly visible by a lens. 



Streak and Bruise. — White or whitish. 



Is very tough, heavy, and breaks with difficulty under 

 the hammer. 



Sometimes so very tough, that a piece of the size of a man's 

 fist will resist completely the attempt to break it by a three- 

 pound circular hammer. 



Melts imperfectly before the blowpipe into a black frit. 



Is the hornblende rock of Bakewell, and the primary trap 

 and primary greenstone of some authors. 



Is known to Europeans by the name of black granite, 

 which term is also used by Pinkerton (Petrology.) 



The masses often give a ringing sound when struck by the 

 hammer, like clinkstone, without shewing any difference in 

 the mineral composition. 



Graduates into hornblendic granite and into greenstone. 



Occurs in great profusion associated with granite, forming 

 hills of piled globular masses, exactly similar to the hills of 

 granite. 



Occurs in the schistose series, as varieties in the structure 

 of dykes of trap, but never in beds. 



Has a perfect rhomboidal cleavage, and is used as building 

 material sometimes. 



Hornblende Slate. 



To prevent mistakes, it might by some be thought best to 

 reject this term altogether ; but if that was done, it would then 

 be necessary for us to use or invent new terms, and I think 

 we should find greater inconvenience from increasing the 

 already too extensive terminology of rocks, than from using 

 old terms in a new sense. I therefore propose to retain this 

 old name, and to confine its use as now defined. 



By common use, the term has been applied to a rock of 



