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Mineralogy of Southern India. By Captain J. Campbell, 

 2\st Regiment, M. N. I. 



I fear that the subject of petrology in India will hardly be 

 considered an interesting one, except to the man of profess* 

 ed scientific attainment, or to the tyro who may be seeking 

 information. To the first, the publication of the crude re- 

 marks of my note-book will afford an opportunity of iden- 

 tifying the various rocks, which I have met with in Southern 

 India ; while to the latter, the various notes and extracts 

 from the published works of authors, will serve as an index 

 to books, where he can procure more complete information, 

 and where the subject can be fully studied. I shall not at- 

 tempt to classify the rocks, but give the names in the irre- 

 gular order as I find them entered ; as any more perfect 

 attempt at arrangement, would lead to a consideration of the 

 principles of the science of ,c Descriptive Petrology," a sub- 

 ject on which I purpose hereafter to hazard some remarks, 

 after the manner of Dr. Macculloch's work on " Rocks." 

 Black Diallage. 



This beautiful rock is well known in Southern India as 

 forming the famed pillars of Sultan Tippoo's tomb at Se- 

 ringapatam. Buchanan Hamilton first called it Hornblende 

 Rock, to which it bears some resemblance, and the error 

 which he committed has been copied by a number of care- 

 less observers, who could not plead the want of leisure, 

 and the pressure of business of collection, which is a suffi- 

 cient excuse for Buchanan's mistake ; and some hasty and 

 prejudiced men have got in a rage at their blunders having 

 been pointed out. The remarks of both Capt. Newbold, 23rd 

 Regt. M. N. I. and myself, shewing that it was not Horn- 

 blende Rock, appeared simultaneously in the Madras Journal 

 of Science ; but I believe priority is properly due to Capt. 

 Newbold, who visited the locality before me, though I was 

 not aware at the time of my visit that he had been there. 



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