62 
Uncords of the Geological Survey of India. 
[v()T.. VII. 
east; and even, that special local depressions took place to the north of that axis: not only 
are the same geological horizons found at about the same level on both sides of the ridge, 
upon which intermediately remnants of these very beds are found at much higher levels, but 
also, as is very clear in the case of the Rongreng basin, steady local sinking took place, 
the nummulitie limestone being found in the middle of that small area at the river’s level, 
while the cretaceous sandstone passes up to a considerable height on the spurs of the adjoin¬ 
ing hills, no high dips being introduced. 
It is interesting to trace the apparent connection of these effects of disturbance with 
pre-existing conditions. The manner in which the coal occurs in the Darang basin strongly 
suggests that its limits are to some extent aboriginal, and therefore that the Semsang 
valley itself was lined out in precretaceous times. At the Gaidgithem outcrop and also in 
the Semsaug there are about fifty feet of sandstone between the seam and the gneiss. But 
as it rises along the spurs to the north and west, one finds a far greater thickness of sand¬ 
stone without any sign of the coal, which is thus simply overlapped ; the beds on the high 
ground, even in contact with the gneiss, being of a higher horizon than the coal. Half a 
mile above the main outcrop in the Semsang there is on the right bank a cliff of sandstone 
resting on gneiss, and at forty feet from the base there is a highly carbonaceous shale repre¬ 
senting the coal seam. 
The manner in which the sandstones are banked up against the Tura range, and fill 
up inequalities in its surface, is quite conclusive on the same point. The spur on which the 
station of Tura stands has a midrib of gneiss, packed in sandstone, through which the old 
ravines have been re-excavated. On the section through Siju and Baduri this would not appear, 
the crushing having assumed a peculiar and intense form ; the separating rib of gneiss, here 
representing the Tura range, is only four miles wide, and at the base on both sides the coal 
measures lie at nearly vertical angles against the gneiss and parallel to its surface, while 
high on the intervening ridge patches of the same rest flatly. Thus it would seem that 
elevation by lateral compression takes effect by increasing existing inequalities ; as would 
indeed result from the crushing of a series of inverted arches. 
Os THE DISCOVERT OF A NEW LOCALITY FOR CoPFER IN TIIE N.1RBADA VaLLEY, i>y 
V. Ball, Esq., m, a. 
The Bijour or submetamorphic rocks of India have, as has been predicted from their 
character, proved the principal source of the useful and precious metals which have hitherto 
been found in this country. The slates, quartzites, and schists which compose the Bijour 
formation resemble in their lithological characters those metamorpkio rocks which in all 
countries are the most productive of metalliferous deposits. 
The discovery of a deposit of copper now to be recorded was made towards the end of 
last year, on a small island in the Narbada river close to the Birman ghat. The gentleman 
to whom the sole credit of this discovery belongs is Mr. Charles Maynard, agent of the 
Narbada Coal and Iron Company. Being well acquainted with the appearance of the ores of 
copper, some stains of the blue and green carbonates upon the rocks attracted his attention. 
He at once determined to open up the ground with the view of ascertaining, so far as possible, 
the extent and character of the deposit. 
On the 11th of January, I visited the scene of operations and found that a ‘ drift’ had by 
that time been driven down to a depth of nine or ten feet. This gave me an opportunity of 
examining the character of the deposit. The rock in which the ore occurs is an argillaceous 
