60 MEDDLEMISS : THE GEOLOGY OF IDAR STATE. 



It is possible that these Mundeti and Kherod series, not only 

 ... , f a fiord striking evidence of this mefamorphie 



A possible order ot . ' . . 



metamorphism imli- process from sedimentary material, hut also 



catecl - may indicate something of the early steps of 



that process. For it would seem that the first additions to 



the sedimentary quartz and calcareous material, consequent on 



regional or other metamorphism, was the differentiation of granules 



of pyroxene in the Mundeti area, and of hornblende in the Kherod 



area, which in the more pronounced forms of the same rocks 



became more or less united into irregular poikilitic plates or into 



lon< T blades. To these also were added grains of sphene and small 



plates of biotite. The addition of other minerals, such as wollast- 



onite and idocrase. seems to coincide in the Mundeti area with the 



additional thermal action engendered by the adjacent masses of 



Idar granite, whilst at the same time the quartz and caleite 



disappear as separate minerals. 



This is as far as the direct evidence takes us in these two areas ; 

 but. if we may reason from this that the 



Other speculations. . r . . . . 



more intense form 01 metamorphism shown 



by the calc-gneiss of the typical areas must be due to other superin- 

 duced causes, then it might be permissible to speculate whether the 

 introduction of felspar in large amount, and especially microcline. 

 into their composition, may have been due to pncnmatolitic effects 

 of the aplite veins, or by means of the aplite veins consequent 

 on dynamo-matamorphism, which thus ultimately must be held 

 responsible for the granulitic condition, and also the hybrid 

 constitution, of the main mass of the more typical calc-gneiss, a 

 conclusion that would seem to be in harmony with those arrived 

 at by Fermor and Burton in the Central Provinces. 



Before leaving the subject of the Mundeti series altogether, 

 , , ... a few details must be <>iven to illustrate its 



Irregular junction © 



with the Delhi rather peculiar position as regards the sur- 

 Quartzite. rounding Delhi Quartzite. If it is realised 



that the strike and dip is everywhere very steady throughout the 

 dozen or so little hill-groups of these rocks, and that the strike, if 

 continued beyond the outcrops in either direction, would run directly 

 into that of the two Delhi Quartzite hill areas lying N.N.E. and 

 S.S.W. of it, it will naturally be asked : do the former rocks 

 really thus come suddenly to an end, and, if so, by what 

 means ? 



