ARAVALLI SYSTEM. 59 



which are obviously but little altered grite or quartzites. the latter 

 being used and exported as a hone ; likewise slaty rocks, such as 

 •A)\) and 4 2 oo- which as a whole are in no ways different from ordi- 

 nary slightly mctamorphie members of any sedimentary series. 



If we admit that the coarser examples of these Mundeti rocks, 



especially those with idocrase. diopside. wol- 

 Calo-eneisa aspect in i„ j._ _:j. 1 1 «»•.*»., 



kheMundetiSeiL; lastomte and sphene. are sufficiently like some 



oi the calc-gneiss varieties (and ! think the 

 resemblance is exceedingly strong), it follows that rocks of a calc- 

 gneiss aspect have been produced, here in the Mundeti area, from 

 a series that contains abundant traces of a sedimentary origin, not 

 only by the presence of clastic quartz grains, with distinct bedding 

 in some cases, but also by the fact that ordinary grits and Iitfcle- 

 altered slaty rocks and limestones (Nos. A 5 n , '-J\ and - ° 



v 400' 400 ' 4 3'" 



respectively) take a part m the series and are interbedded with the 

 more metamorphosed varieties. 



The Mundeti series, in fact, seems to illustrate the actual transi- 

 tion from a sedimentary type of deposit to a 



Theoretical sienific- .1 11 , n . ', ...... 



ance of this, thoroughly crystalline rock indistinguishable 



from certain varieties of the calc-gneiss ; and, 

 therefore, notwithstanding its detached position, separated by some 

 miles from the calc-gneiss area, it may be regarded as strong evidence 

 in support of the theory of the ultimate sedimentary origin of the 

 calc-gneiss. 



A point of some theoretical importance, illustrated both by 



the Mundeti series and the Kherod amphi- 

 Ab*moe of aplito bo]ito . ]imostonos is the t()ta] ^^ rf J^ 



cline, in particular, and of felspar, generally, 

 in them. It seems reasonable to connect this absence with the 

 total absence of any plexus of aplito veins in them, such as. on the 

 other hand, is so marked a feature of the highly altered calc-gneiss 

 and of the biotite-gneiss. 



Another point that tends to link up the three calciferous 



1-Vatlur fonns of serics int() a variously metamorphosed chain 



pyroxene and amphi- of calcareous sediments, is the peculiar filigree 



or feather forms taken by the pyroxene in 

 the Mundeti, and by the amphibole in the Kherod series, which 

 may perhaps be regarded as constituting a certain parallelism 

 between the two, sufficient at least to argue an analogous mode 

 of origin. 



veins. 



