MADRAS JOURNAL 



OF 



LITERATURE AND SCIENCE. 



JSfo. 12.— July, 1836. 



1 — Notes on the Geology of the Country, between Madras and the Neil- 

 gherry Hills, via Bangalore and via Salem. — By P. M. Benza, Esq. 

 M. D. of the Madras Medical Establishment. 



" What benefits has not Geology reaped from the activity of indus- 

 trious individuals, who setting aside all theoretical views, have been 

 content to exercise the useful and entertaining occupation of collecting 

 specimens from the countries which they visit."* J. F. W. Herschel. 



Before entering into the detailed remarks on the geology of the 

 places I passed through, I think that a concise statement of the geo- 

 logical features of the plain near Madras, would be of some utility 

 to the generality of readers, inasmuch as it would make them ac- 

 quainted with the names and nature of the rocks, which they must 

 have seen often, and to which reference is frequently made in these 

 Notes. 



Granite seems the lowest rock in almost all localities of this plain, 

 and it is composed, in general, of the three usual minerals, quartz, fel- 

 spar and mica, their relative proportion varying occasionally (No. I), f 



In almost all the borings for the water, and excavations for tanks and 

 wells, which I have had an opportunity of visiting, granite has been 

 always the lowest rock. 



This rock is observed also at the surface of the soil, forming cluster- 

 ed masses of rock, or small eminences, in many parts of this plain ; 



* A Preliminary Discourse on the study of Natural Philosophy, page 133. Lardner's 

 Cabinet Cyclopedia, 1831. 



+ The figures refer to specimens, intended for deposit in the Museum of the Society.—- 

 Editor. 



