60 GEOLOGY OF THE SON VALLEY, ETC. 



planes of cleavage. Under the microscope it is seen that only the 

 centres of the quartz-grains subsist ; these are greatly elongated in 

 the direction of the cleavage and show considerable strain-shadows. 

 The outer portion of the grains is broken into a fine quartz-mosaic 

 that cements the fragments together. Some flakes of white mica are 

 visible, also lying in the direction of cleavage, but in such a granu- 

 lated rock it is impossible to say whether it is an original constituent, 

 or whether it may not be a secondary transformation of felspathic 

 materials which may have been originally contained in the rock. 

 The quartzites obtained from the northern outcrop of the Agori 

 band form a great contrast with the rock just 

 described on account of their much less meta- 

 morphosed character. The coarsest grained is specimen y- 1 ^- which 

 was collected north of the most northern range of Agori quartzites 

 on the road from Khattai to Maoghun, unfortunately not in situ. 

 But by comparing it with other specimens which have been found 

 interbedded with the slates, its mineral characters are found to agree 

 completely with them, so that there seems little doubt that it belongs 

 to that same age. In the hand-specimen it is a very hard compact 

 rock containing felspar in such large proportion that it might 

 almost be called an arkose. The felspar gives it a pink colour 

 in the hand-specimen. Under the microscope both the quartz and 

 felspar are seen to form well-rounded grains. The quartz shows 

 strain-shadows much more pronounced than is generally the case 

 with the Vindhyan sandstones and exhibits even a tendency to 

 pass into a mosaic ; but it is never granulated as in the rock from 

 the southern boundary. It is true that the rock does contain 

 some portions of quartz-mosaic ; only these were originally in this 

 condition in the sand-grains which they constitute and which were 

 probably derived from some granulitic or gneissose rock. The 

 felspar is all microcline. There is a little magnetite and some 

 ferruginous cement between the grains. 



The next rock, specimen -fifa , occurs in the Piperwani ri\er, in 

 this same neighbourhood, just north of the most northern range 

 ( 60 ) 



