1840. J On the Advancement of Geological Science in India. 85 



remarks, without acknowledging the great assistance I have received in 

 these labours from Dr. W. Gilchrist, of Hoonsoor, and regretting that 

 his state of health has prevented his making public his own observa- 

 tions on 'hat part of the country. To Mr. W. Burr also I am indebted 

 for several valuable hints, which his great practical knowledge of the 

 science in England have enabled him to otFer in a late conversation. 



Since the above remarkes were composed, the 25th No. of the Journal 

 has come to hand, with the Editor's remarks on some errors of Dr. 

 Benza's which I have pointed out. It was by no means my intention 

 to point out, or to prove, the errors of any particular individual, but to 

 shew the disadvantages arising from neglecting the chemical composi- 

 tion of a mineral. To shew this practically, I selected those errors 

 committed by Dr. Benza, whose well known practical information, 

 might be supposed to preserve him from such mistakes. As it would 

 weaken the force of my argument to allow that the rock in question is 

 so plainly not hornblende, I must remark, that my specimens which are 

 broken from the basement of the pillars of the old durbar, would defy 

 the most experienced mineralogist to say what the composition of the 

 rock is. The colour is exactly the same as hornblende rock, the fracture 

 is granular, the structure granitic, and it in no way resembles any 

 variety of steatite. On referring to No. 12 of the Journal, page 13, it 

 will be seen that Dr. Benza by no means examined the rock carelessly, 

 for he most minutely and correctly describes the character of the /roe- 

 ture of the rock, and I must confess, that the only character of the rock 

 which led me to guess it was not hornblende, tvas its brittleness, while 

 toughness is a characteristic of all hornblende rocks. 



I was not aware when I pointed out the mistake about the rock, that 

 Lieutenant Newbold has anticipated me in the remark. The Editor in 

 his remarks affords an instance of the incorrect manner in which mineral 

 names are sometimes applied. He remarks that the rock is plainly a 

 species of steatite. Now, some of the characters of steatite are soft- 

 ness—is easily scratched, yields to the nail, feels greasy, is pulverized 

 with difficulty, and contains little iron ; while the rock in ques- 

 tion possesses opposite characters to every one of those enumerated. Re- 

 garding the eurite, I must allow that 1 chose a bad example ; but from 

 the tenor of the former remarks, it will be easily seen that the point 

 is not worth contending. In the third remark about the silicious schist, 

 the Editor affords an opportunity of shewing the disadvantages of not 

 defining mineralogical characters. Granite in India is often schistous; it 

 is silicious, therefore it is silicious schist. If its granitic character is ad- 

 vanced, we will take the lamellar quartz rock of Norway, alluded to 

 before. This then is a silicious schist. But, the being silicious cannot 

 be considered a distinguishing character of any mineral ; for there is 



