ARAVALLT SYSTEM. 57 



in a sedimentary rock. There is also a little sphene and (?) some 



zircon. No calcite or other rhombic carbonate is detected in this 

 specimen. The attempts at crystallising, on a relatively large scale 

 of what are here interpreted as skeleton plates of pyroxene, doubtless 

 account for the extreme toughness of the rock under the hammer. 



The following similar examples of this variety of the Mundeti 

 series are taken from various localities. No. .{j 3 (12350), from 2 

 miles north of Mundeti. is almost identical with the one last de- 

 scribed. No. ^\ (12346), from the eastern edge of the 1333 feet 

 hill, is dark and variously banded and with much iron ore (pyrite) 

 in filigree areas. No. 3 -,, 9 7 (123 IT), from the western edge of the 

 hill 1 I miles north of Mundeti, and rather near the granite intru- 

 sion, is a pronounced greenish-grey in colour, extremely tough, 

 and has the filigree plates of pyroxene much larger and better 

 developed than in previous specimens. Air occasional cleavage 

 direction is seen in poikilitic plates giving extinctions of about 

 40°. ' The general effect in the thin section of this rock is as of 

 a number of these pyroxene plates extinguishing alternately in 

 the field of the microscope. 



Certain brecciated forms of the hornstone-like variety are re- 



Breccia,! torn, of ^"""^ ** NM ' M> ^^ *»* M 



homsione variety. (12345), from the northern edge of the main 



hill-mass near some small intrusive bosses of 

 the Tdar granite or granite-porphyry, and also near where the sharp 

 line of division between them and the Delhi Quartzite lies, just 

 to the south of a small "tank" or reservoir. In these specimens 

 examples of the darker variety, brecciated in its own dark tints, 

 and including coarse-grained, lighter-coloured fragments, are most 

 common [££%) ', but the lighter variety also occurs with angular 

 brecciated lumps of the dark blue-grey kind contained in it 3 2 , K . 

 The northern slopes of the 1.153 feet spur, south of the tank." are 

 fairly well plastered with this brecciated variety, which does not, 

 however, seem to extend along the line of strike, but to be confined 

 to this one line across the strike of the beds. It is therefore pro- 

 bably a fault breccia. 



Specimens jfa (12313). collected from S.S.W. of 1,153 feet hill, 

 v • . .,, ., 3 miles north of Mundeti. and ,. 2 " (12318, PI. 11, 



Variptv Willi idoerasc £ . , ■,-,•■, ° ' 



and wollastonito as "£• •>), "'om 1 J miles north of Mundeti, lie close to 



"raii'it?. ^^ ° f U " r fete Idar P* ailite intrusions. The ground- 

 mass of these rocks is a pale grey in colour, 



