Chapter III. — Formations overlying and underlying the ViNDHYAisr 



ROCKS. 



Before commencing the description of the A^indhyans themselves, 



we shall enumerate the different formations which 



Older formations. t,i ^ • -i c> i • 



under-and over-ne them, or which are louncl m 



their vicinity, but it will be unnecessary to attempt any detailed des- 

 cription of these. Some have been abeady described in these Memoirs, 

 and reports on others will make their appearance before long, while the 

 geolog-y of some portions is as yet too little known to justify any detailed 

 account of them. 



Gneissose rocks make their appearance in three distinct and widely 

 separated regions. The largest of these is in Bundelkund, where they 

 occupy the great 'bay' included in the curve of the Kymore scarp between 

 Allahabad and Gwalior, underlying unconformably aU the other formations 

 of that country. They also occupy a large tract in the Sone valley, 

 intervening between the slate or schistose series and the coal-bearing 

 rocks to the south, and are again found in the Nerbudda valley at the 

 eastern end of the Dhar forest. Gneiss also underlies the Vindhyans to 

 the west of Neemuch beyond the limits of our map ; there is as yet no 

 reason for disbelieving that these separate spreads of gneiss belong to the 

 same formation. Descriptions of these rocks in Bundelkund may be found 

 in these Memoirs, Vol. II, p. 49, by Mr. H. B. Medlicott, and in the 

 Records, Vol. I, p. 69. The Nerbudda gneiss has been reported on by 

 Mr. J. G. Medlicott, Vol. II, p. 120. 



Between the gneiss and the lower Vindhyans in the Sone valley, 

 there is a very large development of shales and schists with other subor- 

 dinate varieties of rock, constituting a series to which no definite name 

 has as yet been attached. It seems not unlikely that the further ex- 

 amination of these rocks may show that they include two distinct series, 



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