74 FOOTE: GEOLOGY OF THE BELLARY DISTRICT. 



CHAPTER V. 



THE LOWER TRANSITION, OR DHARWAR ROCKS. 

 This great system of submetamorphic sedimentary rocks, with 

 numerous contemporaneous trap flows, was not recognized as distinct 

 from the South Indian gneiss till the geological survey had been 

 extended by me across the Raichur Doab, and the south of Belgaum 

 and the centre of Dharwar district visited, together with parts of 

 Hypogene schists of Bellary and Mysore. Newbold had included 

 Kewbold - it among his " hypogene schists ", which he 



thought had been broken through by the granitoid rocks which form 

 so large a part of the Bellary district and adjoining parts of the 

 Deccan plateau. Herein he was mistaken, for the granitoids, as a 

 whole, are much older than the Dharwars and form the base on which 

 they rest. Only a few veins of pegmatite are intrusive in the Dhar- 

 wars, and these he appears to have mistaken for intrusions emanat- 

 ing from the general granitoid mass, whereas they are really of post- 

 Dharwar age. 



The greater mass of the Dharwars consists of schists, horn- 

 blendic, chloritic, and argillaceous; but the associated traps, 'and more 

 especially the haematitic quartzites, from their superior hardness and 

 durability, occupy in many places much the most prominent posi- 

 tions; while, from the same reasons, the taluses they have given rise 

 to in the hilly tracts are of extraordinary extent, and cover up much 

 of the softer rocks and mislead one as to their real extent. 



The Dharwar rocks were originally deposited over very much 



Original extent of the lar g er areas than those the y now Occupy,- and 



Dharwar rocks. ver y p ro bably extended across the whole, or 



nearly the whole, peninsula. How far they may have extended to 

 the north it is not possible at present to say, for the northern extremi- 

 ties of several of the Dharwar tracts are hidden under younger geo- 

 logical formations, e. g. } the Kaladgi and Bhima series, and the 

 Deccan trap along the upper course of the Kistna river. To the 

 ( 74 ) 



