GEOLOGY OF INDIA. ' 21 



that they are less inclined to theorise than those of other countries : in- 

 deed, the series of their rocks is so complete, that they have not needed 

 it : their labours have consisted in the accumulation of facts, and the 

 scene of their operations being so confined, compared Avith the extensive 

 field in other countries, they have been able to visit almost every forma- 

 tion with minute investigation This we have no present hope of being 

 able to accomplish in India; but we may, nevertheless, follow their exam- 

 ple in the simplicity of our arrangement, and in the precision of our no- 

 menclature ; and it would seem that our adoption of the synoptical arrange- 

 ment above mentioned, as far as practicable, by leading to an uniformity 

 in our pursuits, and, what is still more important, to an identification of 

 our principal Geological Strata with those of Europe, will preserve us 

 from many errors : it will, besides, prove advantageous in rendering our 

 descriptions more intelligible to all persons in England, who may be in- 

 terested in the Geology of India. 



NOTE. 



The occurrence of basaltic veins, traversing the granitic ?-ocks of Central and 

 Southern India, is not unfrequent, and has been particulai'ly noticed by Dr. Voysey. 



In travelling from Madras to Man galore, many years ago, I observed one of those 

 veins possessing peculiarities that may render its description somewhat interesting to the 

 Geologist. It occurs in the rocky bed of a small detached branch of the river Caveri — 

 at a spot distant about two miles west from the fort and island of Scringapatmn here the 

 prevailing rock is sienitic granite, which, on the left bank, rises in nearly a perpendi- 

 cular face to about fifteen or twenty feet above the stream. In this rock, there is a vertical 

 (Jijlce, or vein of compact basaltic trap, ten or twelve feet broad, and of uniform thickness 

 (its sides being parallel) from top to bottom — a small vein of black scaly hornblende, about 

 two inches in thickness, traverses the sienitic rock, obliquely, and it is distinctly perceptible 

 that this vein has been disrupted by the ixihyn dyke, for, in the midst of the basaltic vein, there 



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