35 



Chapter 6. — Bijawue. Series. 

 Besides the granitoid and gneissoid metamorpliic formations, there 



is another series of rocks largely developed in the 

 Intermediate in cha- 

 racter between metamor- western Nerbudda vallej; which while less crys- 

 phics and Vindhyaus. . . t i -i • ti 



talline than the gneissic, and while occasionally 



showing scarcely any traces of alteration^ is nevertheless in general much 

 more metamorphosed than the Vindhyans and other stratified rocks 

 of newer age. This formation had never previously in the Nerbudda 

 valley been distinguished clearly from the true gneissic metamorphics, 

 although its characters were partly pointed out by Mr. J. G. Medlicott 

 in Vol. II of these Memoirs. 



The rocks to which these remarks refer were first met with in the 

 course of the present survey, in the country between Nimawur and Chand- 

 gurh. They were again recognised in the Dhar forest, where they are 

 PecuHar rocks com- exposed over a large area, and they were subse- 

 V^^^^' quently met with near Bagh and elsewhere. 



Two rocks, composing no small portion of their mass, are indeed so 

 peculiar and characteristic that it would be impossible to pass them over- 

 without notice. 



The first of these rocks is a very silicious limestone composed of 

 Laminated silicious ^^^ alternating laminffi of carbonate of lime and 

 limestone, quartz, the lime generally predominating in 



' amount. This rock has a distinctly bedded appearance, whichj however, 

 is fallacious, for the regular succession of thin bands of quartz or lime- 

 Lamination not due to stone which simulate stratification are in reality 

 beddmg. lines of lamination generally corresponding to origi- 



nal cleavage planes, and may be considered an incipient stage of gneissoid 

 structure. This may be suspected (and was so) from the very great 

 steadiness of dip and strike, the former at high angles, seen in these rocks. 

 But far better evidence was obtained to prove that this structure was 

 not due to the original planes of stratification. In some instances 



( 197 ) 



