Records of Ike Geological Survey of India. 
182 
[VOL. X. 
truly represent the order and position of an original sequence seems, to be the more legitimate 
one to draw. 
The limits available for the purpose here will admit of only a very brief sketch of the 
more prominent features of these rocks. 
Valley of the Mahanadi, feom Cuttack to Sox pur. —Passing westward from the 
sandstones of the Atgarh basin, along the south bank of the Mahanadi, the rocks seen consist 
chiefly of varieties of garnetiferous gneiss. These are best exhibited in the Barnaul Pass, 
where the river runs almost due north-west south-east between two sugar-loaf peaked ridges, 
the dip of the beds being from 40° to 80° to north-east. 
Towards Horbonga, and thence to Sonpur, the rocks consist chiefly of coarse porphyritic 
gneiss, which occasionally shows strikes varying from north-west to west-north-west; hut not 
uncommonly the rock is massive, and exhibits no distinct bedding or foliation. 
Valley of the Mahanadi, feom Sonpue to Sambalpue. —Between Sonpur and 
Ginka the rocks, where seen, consist, for the most part, of granite, with quartz veins. In the 
Ong River there are some hornblendie gneisses, and further on, fine-grained bacillary gneisses 
and quartzites. Close to Binka there is a schistose quartzite, similar to a rock seen in the 
station of Sambalpur. Its strike is east 35° north, west 35° south, with a dip of 50° to 35° 
south of east. Further north, at Turam, in the bed of the Mahanadi, there are schistose and 
granitic gneisses, striking north-north-east, with a dip of 60° to east-south-east: these [form 
the long hill ridges on the eastern hank of the river. 
In and near the station of Sambalpur, the rocks are chiefly granitic and porphyritic 
gneisses, associated with which is a band of quartz schist. The beds are, for the most part, 
vertical, but in places there appears to be a dip towards the east-south-east. The strike 
varies from 10° to 30° east of north. A point about three miles east of Sambalpur seems to he 
the centre of a great synclinal basin, the rocks on all sides consisting of granitic and syenitic 
gneisses, with schistose and shaly alternations. 
Area North of Sambalpur. —Ten miles north of Sambalpur is the Kudderbuga 
range, formed chiefly of quartzites, which are much more strongly developed in the western 
half of the range than in the eastern. 
In the Bonum River, south of Katikela, the section exposes a metamorpliic conglomerate. 
The matrix is quite schistose, but very dense and hard, and it includes rounded pebbles of white 
quartz. The same rock occurs three and half miles further north, in the bed of the Sumpai, 
south of Dulki. Lodes of brown haematite (altered magnetite) occur in the rocks near Kudder¬ 
buga, more particularly to north of Rarimoul. The principal one seen there consists of a 
quartz-iron breccia, which strikes, with the surrounding rocks, to about west 15° north. The ore 
used by the natives is taken from the washed debris of this lode. Close to Talpucliia there is 
a small hill of fault rock and gossan. It is possible that a metallic lode may exist there. 
Pebbles of carbonate of lead were found in the alluvium about a mile and a half to the south. 
The last section in this tract of country which there is space to notice here, is that 
afforded by the (Gangpur) Sumpai, a tributary of the Ebe. Close to Ivujerma the bed of the 
river discloses a thickness of 50 to 60 feet of blue limestone, dip 40 south-south-east. 
Underneath these are somewhat sandy quartzites, and the two rocks taken together are not 
unlike the Vindhyans seen near Padampur. Nearer the village, however, these rocks appear 
to be conformable to and dip under granitic gneisses, which are in close proximity; but no 
actual junction is seen. A portion of the limestone is of inferior quality, containing tremolite; 
but much of it is a strong pure rock, which ought to prove valuable, should occasion arise for 
its employment. 
