of Salem and Bar ramahal. 175 



cc 



s 



granular hornblende," and where the grains are so large 

 as to deserve the name, and render visible the form of the 

 crystals, it may be termed " crystalline hornblende." The 

 above descriptions are not, I think, likely to be misunder- 

 stood, and their use is not at variance with the application 

 by other writers. 



Basalt, the rock in question, may be defined thus : — 



Colour black or greyish black ; fracture irregular or semi- 

 conchoidal and smooth ; structure compact, homogeneous 

 and massive, and the lens shewing no apparent aggregation ; 

 streak none ; hardness, does not yield at all to the knife ; 

 very tough, resisting a very heavy hammer, and flying into 

 sharp fragments, to the great danger of the knuckles and 

 shins ; melts easily into a clear black glass, by which it is 

 distinguished from Lydian stone or bassanite or flinty slate, 

 which occurs also in this district, but is quite infusible. 



It is found in granite as long veins, sometimes many yards 

 in length and only an inch in width, which run through the 

 mass with a tortuous course, sometimes interrupted, as 

 above mentioned, in quartz veins, the ends joining as if dis- 

 rupted, and drawn out by some motion in the parts of the 

 mass, and the ends occasionally are seen merely slipped 

 on one side, with a very fine thread joining them. Some- 

 times it is seen embedded in the body of a mass of granite, 

 enclosing an entangled breccia of granite, the body of the 

 basalt being diffused into the granite by fine, irregular and 

 tortuous veins. In this manner it also occurs in gneiss ; some- 

 times it is seen as very fine and thin short veins, which fine 

 out at each extremity ; insulated in the body of the granite and 

 in the same way in gneiss, crossing and sometimes coinciding 

 with the lamination. 



The above may be observed in the granite hills three 

 miles S. E. of Salem, and in a small range of hills two miles 

 from Royacottah, on the right and left of the road to 

 Kistnagherry. Dr. Benza has described basalt dykes in 



