36 ball: geology of auhunga and hutar coal fields. 



On the hill east o£ the village of Kokaroh there is a vein of white 

 rock consisting partly of calc-spar and partly of 

 ^^Labradoritewith calc ^ j^jj^eral which has been analysed by Mr. Mallet, 

 who regards it as an abnormal form, of labradorite.^ 

 Passing now to the description of the rocks in the area surrounding 

 the Hutar field, it is found that they present no general characters 

 which would serve to distinguish them from those in the neighbour- 

 hood of the Aurunga field, but there are several points about them 

 deserving of notice. At the north-east end of the field they are 



traversed by clearly defined trap dykes, no similar 

 Trap dykes. 



intrusions having been met with elsewhere. 



On the south a lofty range which runs east and west, and is continuous 

 with the one forming the southern limit of the Aurunga field, is formed 

 of granitic gneiss, with quartz and granite veins of ordinary character. 

 This ridge is very possibly connected with a line of faulted upheaval. 



North-west of the field in the region surrounding Ramkunda, the 



metamorphie rocks are much decomposed, and there 



Neiglibourliood of ^^,q vfide tracts of raviny, unreclaimed land, covered 



by sal and bush jungle. The map well illustrates 



the character of the network of streamlets and ravines abounding in 



that neighbourhood. Where rock has been conserved, it mostly appears 



in the shape of bosses and tors or a black syenite-looking rock, some of 



which is indeed lithologieally true syenite, but more commonly the 



colouring mineral is black mica and not hornblende. 



In this region, south of the village of Manjuri and at the mouth 



of the stream which, rising in the Bijka peak, 



Stilbite. . , . • 1 1 • n 



joins the Atee river, there occur several veins of 



stilbite. This mineral, though well known to occur in metamorphie as 



well as volcanic rocks, has been but rarely met with in India in this 



association. I am unaware of the existence of any record of its having 



been found elsewhere in this country in equal profusion and beauty. 



» It is partially decomposable by HCl. The filtrate contains alumina and lime. It 

 does not gelatinize with acid. It contains no water. Hardness 6" 5. ' 



{ 36 ) 



