LOWER TRANSITION ROCKS. g3 



have quite a cindery appearance. The trappoid above referred to 

 then seems to take the place of the haematite quartzite, and no 

 connection between the latter and the haematites of Birrabbi hill is 

 traceable. 



The basement formation of the series at the east side of Birrabbi 

 hill is grey schist (argillite). Here, as in so many places in this and 

 other bands of Dharwar rocks, the hills increase in height and import- 

 ance in proportion to the greater development of the haematite rocks 

 in them. 



Two or three very small and unimportant beds of crystalline 

 lime-stone are to be found among the schists a little way up the slope 

 of the hill south of Birrabbi hill. 



The succession of formations in this Kunchur tract, though appa- 

 rently very simple and obvious, is really far 



Succession of forma- 

 tions in the Kunchur from being clear. If the apparent sequence from 



the argillites of the Hollal plain south-eastward 

 to the thin platey quartzite at foot of the Hallagilwadi hills were true, 

 it would represent a series between 70,000 and 80,000 feet thick, which 

 is absolutely improbable. There has evidently been a great redupli- 

 cation of the different members of the series, and this has probably been 

 brought about by three great faults or systems of faults by which the 

 haematites are made to appear as four series instead of one or two at the 

 utmost. In the accompanying diagram ( Plate I ) I have attempted to 

 explain what appears to me a probable solution of this puzzling section, 

 In the absence of organic remains in these rocks it is impossible to 

 establish geological horizons on merely petrographic data, where dis- 

 tinct and unmistakeable stratigraphical evidence fails. 



Intrusive traps in the Kunchur band are few in number, and none 



present any peculiarity of interest on micro- 

 Trap dykes. 



scopic examination. 



The large dyke which crosses the hilly haematite beds about 5 

 miles south-east of Hollal in its northern part includes many gneissoid 

 fragments enveloped in the mass. 



F2 . ( 83 ) 



