Z2 BA.LL: GEOLOGY OF AURUNGA AND HUTAB, COAL FIELDS. 



to be distinguished from trap. In association witli these rocks occur all 

 the principal deposits of magnetic iron ore. 



Farther west, in the neighbourhood of Ramkunda, a black micaceous 

 granite, which is occasionally syenitic, occurs over 

 a considerable tract of country. To the south of this 

 the granitic rocks are chiefly remarkable for including very fine veins of 

 stilbite. Towards the Kunhur the hornblendic gneisses disappear, and 

 among the granitic rocks a coarsely porphyritic variety becomes the 

 most prominent form. Throughout the whole area schistose rocks are 

 rare. 



In the country south of our main area rise several lofty ranges of hills 

 which are principally formed of metamorphic rocks, but on some of them 

 deposits of sandstone, trap, or laterite occur, forming distinctly marked 

 caps. The Gulgul and Neturhat pats belong to this latter class and 

 have bases of highly granitoid gneiss. 



To the above general sketch of the distribution it will be well to add 



some further details. Approaching the Aurunga 



valley by the road from Balumath, a very distinct 



ridge of fault rock is met with crossing the road near Pukree and 



striking thence to west-south-west. A mile farther on, at Olherpat, 



there is a considerable exposure of limestone. This 



Limestone. . ,i n i • i i i • n 



consists partly oi highly calcareous gneiss and 



partly of vein-like lenticular masses of crystalline limestone. For about 



a mile and a quarter, or nearly up to the village of Deredag, the road 



crosses the outcrops of similar rocks, the strike being to about 35° east 



of north, with varying, but high, dips. 



In the Chunhat stream the limestone is clearly seen to be cut off by 

 the fault, whose presence was indicated by the already mentioned fault 

 rock. Close to the village of Chunhat the water charged with lime 

 from this source falls over a step in the gneiss, and the evaporation of the 

 spray and drip, extended over a long period of time, has resulted in the 

 ( 32 ) 



