DELHI QUATITZITE SERIES. 109 



to estimate its thickness accurately, but it may be between 40 and 

 60 feet. It resembles the Dev Mori-Kundol steatite. Actinolite rock, 

 ( 4 ^ 3 12433), amphibole rock changing to calcite ( 8 % k. 12434), and 

 calcite and brown opal rock ( 3 -q° 7 1243G), are also associated with 

 the steatite. 



The presence of chromite in this band of altered rock is addi- 

 tionally suggestive of some ultrabasic rock as 

 Origin. , e ! . ,.» . 



the parent or the various modifications re- 

 ferred to above, but the thoroughly serpentinized condition of 

 whatever the rock was makes it impossible to specify it more parti- 

 cularly. Hence in this case, as in that of the other similar 

 occurrences, I have, though with some hesitation, included these 

 magnesian rocks in the section on the Delhi Quartzite, rather 

 than put them into a special class of ultrabasic intrusions, as to 

 which there is no positive evidence. 



The possibly fair thickness of this band of derived magnesian 

 and other minerals, which I estimate as some- 

 thing under 300 feet from the width of the 

 outcrop of surface rock, renders this locality also worth the atten- 

 tion of the mineral prospector. 



The above four localities for these rocks are all 1 have discovered 



in Fdar State, but owing to the tendency 



|o OthOT possible ()f tho accompanying Delhi Quartzite to 



break up into long debris slopes, there may 

 be others hidden from view through the wide areas coloured on 

 the map as Delhi Quartzite. and a few perhaps that I have missed 

 in my traverses. 



(4) Tectonic Relationship between the Delhi and Aravalli. 



Whilst the relationship of the Quartzite series to the younger 



rhvllite series in this region is everywhere 



. 1 '- , «^ lli ;! i,i ^ " { comparatively easily understood on the 



juxtaposition. " j j 



simple supposition that the former formation 

 passes conformably up into the latter by a rapid if gradual inter- 

 bedding, this being recognisable at the surface in many places by 

 the outcrops of intermediate passage layers following con- 

 tinuously round a clearly exposed sinuous line of junction, the 

 same (as we have had abundant proof of) is not true as regards the 

 indirectly deduced relationship between the quartzite and the 



